| 00:02 | All right y'all, I'm gonna go and get started. Um So I'm |
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| 00:08 | a meeting tonight at 7 30 because sucks. Why would I want a |
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| 00:13 | at 7 30? But meeting with people. So hopefully right after the |
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| 00:18 | , we'll be able to sign stuff . I'll send out an announcement whenever |
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| 00:20 | happens. All right, everyone's on same page. No one's getting um |
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| 00:25 | an advantage or anything like that. just be alert that it might be |
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| 00:30 | . If not, it will be tomorrow morning. Ok. Um |
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| 00:35 | I'm having fun with that. Uh , what we're gonna do is uh |
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| 00:40 | going to talk about cell biology, we've kind of done the macro molecules |
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| 00:44 | the biomolecules and now what we're gonna is we're gonna kind of look and |
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| 00:47 | , all right, how is the organized? What are the structures of |
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| 00:52 | cell? And we've, we've mentioned that, you know, in the |
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| 00:55 | , there are hundreds and hundreds of types of cells, right? And |
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| 01:01 | we're doing is that we're just look, it doesn't matter what type |
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| 01:04 | cell there is or you're looking at more or less have these parts to |
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| 01:07 | . All right. So that's kind what the big picture is. And |
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| 01:10 | we're going to walk through the plasm , we'll walk, walk through the |
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| 01:13 | of the side of plasm, we'll through the nucleus and not necessarily in |
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| 01:17 | order. And then afterwards, we're to talk a little bit about transcription |
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| 01:20 | translation. So much of this stuff be reviewed to you at some |
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| 01:25 | right? So you, you should seen this at least one time in |
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| 01:28 | life if you've taken a biology class a life sciences class, right? |
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| 01:32 | One of the best ways to study stuff is to literally draw a picture |
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| 01:36 | a cell. And when I say a picture cell, you make a |
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| 01:39 | and then you put your little tiny in there and then you label them |
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| 01:41 | say what they do. That's probably easiest way to learn this stuff. |
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| 01:45 | right. But you figure out which way works the best for you. |
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| 01:49 | right. So in looking at the , what we're gonna see is we're |
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| 01:53 | focus on these three basic parts, membrane, plasm membrane that separates the |
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| 01:57 | from the inside. All right, what creates a unique compartment inside the |
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| 02:03 | so that the unique um activity of cell can take place excluding the environment |
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| 02:08 | around it. The cytoplasm is where the organelles are now the organelles are |
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| 02:16 | , compartments inside the larger compartments where chemical reactions are taking place. So |
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| 02:21 | are areas set aside for those unique uh uh reactions, those unique things |
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| 02:28 | it does. So just like in home, we talked about yesterday, |
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| 02:31 | being like a kitchen and a bathroom a bedroom and yada, yada |
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| 02:35 | those are places where certain things take . That's kind of what the organelles |
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| 02:39 | . They're like unique environments so that can do their job, right? |
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| 02:45 | then we have the nucleus and the really is an organelle. But we |
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| 02:49 | it aside because we like things that of set out a special. And |
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| 02:53 | like we look at the brain and oh look, the brain is so |
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| 02:56 | . It's a unique organ, it's organ just like everything else. It |
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| 03:00 | the thinking. And so the nucleus like a brain of a cell. |
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| 03:05 | the control center, right? It's all the the genetic material is |
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| 03:10 | And it does all these unique things make it sound like it's unique or |
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| 03:16 | than the other structures. It's it's just another organelle, but we |
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| 03:21 | it aside for this reason. All . So we're gonna kind of walk |
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| 03:25 | these, I want to just first about the cytoplasm. We're gonna get |
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| 03:28 | the plasma membrane later. And I the, the next thing after the |
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| 03:31 | , we talk about the nucleus to off with all the different types of |
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| 03:36 | . All right. So with regard the cytoplasm, this is basically the |
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| 03:43 | found within the plasma membrane. So everything within it is considered to be |
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| 03:50 | . The cytoplasm itself actually has different to it. We've already kind of |
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| 03:54 | the organelles. Those are the structures you can see that are embedded within |
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| 04:00 | material of the cytoplasm. And the environment of the cytoplasm is what is |
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| 04:05 | to as the cytozole. The way can think about the cytosol is that |
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| 04:08 | water plus stuff. All right. we're not going to define what the |
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| 04:12 | stuff is. It's just, there's , there's uh sugars, there's |
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| 04:18 | there's salts, there's all sorts of things floating around in that. And |
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| 04:22 | if you'd like to poke a hole a cell, it would kind of |
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| 04:25 | out, it wouldn't like squirt out water because there's more stuff in |
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| 04:29 | right? So it's just water plus suspended in it. And then |
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| 04:34 | we have things that we don't know to do with them where they're not |
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| 04:38 | as, you know, the, stuff that's suspended in the side as |
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| 04:40 | they're not organelles, what we call are inclusions. And so these are |
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| 04:44 | and far between not all cell have inclusion. Some are specifically designed to |
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| 04:49 | inclusion and what an inclusion is, simply a chemical substance that, that |
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| 04:54 | be defined by those two things. cells that have glycogen will have glycogen |
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| 05:00 | . There's crystals that will kind of fat cells will have lipid droplets, |
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| 05:04 | example, right? That would be inclusion um not us for, for |
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| 05:10 | most part but like flowers and they'll have like pigments in their |
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| 05:14 | right? So the cells that make the petals have pigment inclusions and these |
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| 05:18 | larger structures that are not quite And then some cells will even have |
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| 05:22 | in them, you know, and , the crystal lattice work. So |
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| 05:26 | kind of what an inclusion is. we'll look at something where it's |
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| 05:28 | oh that looks like an inclusion and kind of like, yeah, kind |
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| 05:31 | sort of, right. So that's of the cytoplasm. Now the organelles |
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| 05:39 | , there's basically two different groups of , what we call membrane bound |
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| 05:43 | And so what they have is they uh a unique environment inside them and |
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| 05:48 | have the same membrane that makes up plasma membrane, right? So when |
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| 05:52 | looking at a acha the vale the , the endoplasm reticulum, these structures |
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| 05:59 | membranes that are are are organelles that on its surface, the same sort |
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| 06:04 | material, the phospho lipid bilayer that up this plasma membrane. All |
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| 06:10 | And so what we've done is like said is we've created this unique compartment |
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| 06:14 | that something unique can happen within And that's when we'll go through the |
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| 06:17 | . All right. And so here's of a list of those structures that |
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| 06:21 | uh just mentioned. The other some, some books, mis mischaracterize |
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| 06:27 | mis call them non membrane bound So if you ever see that |
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| 06:32 | just go out there, know what talking about and then you can kind |
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| 06:35 | move on, right. But what referred to are bio molecular complexes. |
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| 06:40 | right. So what you're seeing here you see that word, that non |
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| 06:44 | bound organelle, it's just someone well, I don't know what to |
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| 06:46 | them and they're too lazy to go it up. Right. And here |
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| 06:50 | are large groups of macro molecules. you can think about lots of proteins |
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| 06:54 | together and kind of creating this mass they work or function as a |
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| 07:01 | Now, some that are really easy understand and we're going to look at |
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| 07:06 | are going to be the cytoskeleton. right. So these are gonna be |
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| 07:09 | proteins that create these long strands that create structure. You've heard of |
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| 07:15 | ribosomes is another one that is not bound, but it's an organelle. |
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| 07:19 | has a function. We'll look at and then the centris again, these |
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| 07:23 | going to give rise to cytoskeleton but they're not a membrane bound |
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| 07:28 | So those would be examples of bio complexes. All right, this is |
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| 07:35 | the ugliest picture I could find on internet looks like the I F |
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| 07:40 | And what we've done and we're, we're doing is we're moving into the |
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| 07:44 | organelles. So this is kind of the big checklist time, right? |
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| 07:48 | so the first thing we're looking at the nucleus. So we've cleared everything |
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| 07:52 | of the cell. And what you're at is solely the nucleus itself. |
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| 07:56 | is not the nucleus, this whole is the nucleus, right? And |
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| 08:01 | this is what we consider to be control center of the cell. It's |
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| 08:05 | the brain of the cell. It's the largest, largest structure inside a |
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| 08:09 | . So when you look into a and under the microscope, it stands |
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| 08:12 | as this big circular structure that sits the cell itself. All right, |
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| 08:19 | is where most of the DNA is to be found inside the cell. |
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| 08:22 | the exception to this rule that you up here in the parentheses that mitochondria |
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| 08:27 | its own DNA. So you can't that all the DNA is inside the |
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| 08:31 | because mitochondria has its own. All , this is where DNA replication takes |
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| 08:36 | . This is what we say is for the genetic control of the |
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| 08:41 | So everything that that cell does is to be a function of that |
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| 08:46 | the activity that's taking place inside the . Now, there are three structures |
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| 08:51 | interest here, the nuclear envelope, nucleolus, which is this little circle |
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| 08:57 | and then you can, if you carefully, you can see kind of |
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| 08:59 | darker stuff and the lighter stuff that's to be the chromatin. All |
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| 09:04 | Now, again, that picture is the worst one I could find on |
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| 09:06 | internet. So just bear with So if we kind of focus in |
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| 09:12 | , really closely and look here, can see here's the nucleus all right |
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| 09:18 | there, what you see moving on there is that's the endoplasm cretic. |
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| 09:22 | what we can see here is this and you can see that it's a |
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| 09:26 | membrane, right, you see membrane the inside and it folds on itself |
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| 09:30 | then it starts moving on, it endoplasm cretic. So this is the |
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| 09:35 | envelope, this is what makes up outer wall of the nucleus. And |
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| 09:40 | you can see it's continuous with another , it has associated with it, |
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| 09:45 | structures called nuclear pores. This is allows material to go in and what |
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| 09:50 | out. You can presume or think this structure as serving kind of as |
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| 09:54 | bouncer to a club. If something to go into the nucleus, it |
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| 09:59 | to have the right tag associated with . All right, it has basically |
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| 10:05 | that, that poor can read. if that doesn't have the right information |
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| 10:09 | it, it's not allowed to go . So these are very, very |
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| 10:13 | to, to allowing what goes in what goes out. But one of |
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| 10:17 | thing that leaves is gonna be R A R N A is leaving, |
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| 10:20 | so that it can be transcribed and deal with it or translated and we'll |
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| 10:23 | with that in a little bit. right. So, structurally, it's |
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| 10:27 | of this unique thing you can see here that we have this uh |
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| 10:32 | you see this kind of this network this artist has drawn on here, |
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| 10:36 | stuff over here that's the DNA and DNA is being laid on and uh |
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| 10:42 | through this network of proteins. And it's the way that the cell organizes |
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| 10:49 | the DNA is and where the DNA . So if you think about um |
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| 10:54 | about how, how much DNA you , we have 2020 oh gosh, |
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| 11:00 | blanking now. 24 chromosomes, I'm just, it's an early |
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| 11:04 | right? We have 24 chromosomes uh terms of number of bases, we're |
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| 11:09 | in the mega bases millions upon millions millions of, of nucleotides. And |
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| 11:17 | have something like 33,000 genes is, the estimate that we have right |
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| 11:22 | And so one of the questions, know, when I was sitting in |
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| 11:24 | seat and what you probably should be yourself every now and then is |
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| 11:27 | how does my cell cell know which to turn on and when and where |
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| 11:31 | are? Well, it's because it's organized, we don't know how it's |
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| 11:38 | . We haven't figured that out but it's, it's organized on there |
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| 11:40 | it knows what it's turning on and it's turning off and it's because of |
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| 11:44 | structure on the inside of the All right. Um So this would |
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| 11:51 | like an electron micrograph you can see here is nucleus, see the dark |
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| 11:55 | that's chromatin. The light stuff is chromatin, but it's a different type |
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| 11:59 | chromatin. We'll get to that in a moment. But you can see |
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| 12:02 | the center the thing that looks like eyeball, that's a nucleolus, it's |
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| 12:07 | actual structure inside the nucleus. So kind of like the nucleus of the |
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| 12:12 | . All right. Now, the of this is multifold and we're still |
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| 12:16 | of learning what it does. But of the major things that it's responsible |
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| 12:20 | is making up the ribosome R N of ribosomes. So we're gonna learn |
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| 12:25 | ribosomes in just a minute. This where they come from. All |
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| 12:29 | Uh The other thing that uh they're is so we thought that this was |
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| 12:33 | it does, but we're finding out it actually has other processes in terms |
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| 12:38 | regulations and other things. And I think it's important enough for us to |
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| 12:42 | but that, but that we pointed that something exists inside a cell, |
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| 12:46 | not there just because it, all things do have functions. And so |
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| 12:53 | you know, like when I sat your seat there's stuff up here that |
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| 12:56 | exist and now it's like, you, you know, let me |
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| 12:59 | it to you by the time you're age, which is like, like |
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| 13:02 | years from now. Um That was . I'm old, right. Um |
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| 13:09 | gonna find out that there's a lot things um that we have learned. |
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| 13:13 | , we're barely, we're like kindergartners it comes to biological knowledge, |
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| 13:19 | So nucleus has its own little tiny . Primary is ribosome uh structure. |
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| 13:27 | here's our nucleus and you can see it's surrounded by this structure that looks |
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| 13:34 | a bunch of tubes or a bunch what we call them are tubules in |
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| 13:39 | Cni just think of a cistern, old bowls. OK. And so |
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| 13:44 | structure that surrounds it kind of expands where it's continuous with the nucleus. |
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| 13:48 | saw the nuclear envelope and it formed became endoplasm reticulum. And so you'll |
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| 13:54 | usually in a plastic curriculum, Er All right. There's two basic |
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| 13:59 | . There's the rough endoplasm curriculum. smooth endoplasm curriculum. What's the difference |
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| 14:03 | rough and smooth ribosomes? I was you'd say if one's rough and one's |
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| 14:10 | , one's bumpy, one isn't. right. And again, this is |
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| 14:14 | of those things where someone looked in microscope and said, why this, |
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| 14:17 | looks weird? It's bumpy looking. one isn't, but they look kind |
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| 14:21 | the same. All right. ultimately, what we determined was |
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| 14:25 | that buiness is a series of ribosomes are attached to the surface of the |
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| 14:30 | Curti. So rough er, has , smooth, er does not. |
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| 14:36 | whenever there's differences, that means they're something differently, the rough aplasia |
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| 14:41 | its primary role is the production of that are going to be secreted |
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| 14:46 | or put into the plasma membrane and way that it does. So, |
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| 14:51 | this is a process we're gonna look a little bit later, but just |
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| 14:54 | that you can see it's like, , here are the ribosomes making |
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| 14:58 | What they do is they associate with uh pores on the endoplasm reticulum. |
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| 15:03 | so they insert that protein that's growing then if it's gonna be secreted, |
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| 15:07 | goes completely into the endoplasm curriculum. it's not, it stays um associated |
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| 15:12 | the surface. All right. So is kind of what it's gonna look |
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| 15:17 | . And so that's what those bumps . The ribosome is doing that the |
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| 15:22 | endoplasm curriculum. On the other is a little bit different. It's |
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| 15:25 | tubular in nature rather than these large giant cisterns. You can see |
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| 15:30 | they're trying to looks like a whole of pipes and depending on which cell |
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| 15:35 | looking at, it has a different . And so you can't just look |
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| 15:38 | a smooth end applies in particular and , oh, this is what it |
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| 15:41 | does, it's like, OK, doing something unique here. Now, |
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| 15:45 | it can do is very often it modify proteins. So the idea |
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| 15:50 | is molecules that the cell is taking are sent to the smooth end applies |
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| 15:54 | reticulum. And it has these enzymes are responsible for these modifications. We |
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| 16:01 | glycogen in some of our cells. talked about that already. Right? |
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| 16:06 | have glycogen, liver cells have And what do I do? Glycogen |
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| 16:10 | long chains of glucose? I want release that glucose. What do I |
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| 16:14 | is I've got to chop it So this is a place where that's |
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| 16:17 | happen. This is a place where can make your steroids. This is |
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| 16:21 | place where lipids are being created so some of those lipids that we looked |
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| 16:25 | and it had all those little arrows at things that we said, we |
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| 16:28 | have to worry about those processes taking in a compartment set aside specifically for |
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| 16:34 | to happen. Smooth applies curriculum. thing we're gonna talk about a lot |
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| 16:40 | is gonna be the muscles and how contraction works. Muscle contractions are dependent |
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| 16:45 | calcium. Calcium is stored up or in smooth into plasma reticulum. So |
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| 16:52 | , it's a place where you put this stuff and when it's time for |
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| 16:54 | muscle contraction, you release all the and the calcium comes flowing out and |
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| 16:58 | you pump it back in. So just an environment where you store up |
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| 17:03 | . So you can see smooth curriculum can have lots of different types |
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| 17:06 | roles depending upon what type of cell looking at. So right now in |
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| 17:11 | brain, you should be saying, , smooth end into curriculum does different |
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| 17:15 | . And then when you learn new , then you just kind of |
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| 17:17 | oh, does this get tossed into smooth and apla category? All |
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| 17:24 | So, er, pretty simple. then we move on to the next |
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| 17:29 | along the line, which is called Golgi, the Golgi apparatus. All |
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| 17:33 | . Now, when I think of gold apparatus, what I usually think |
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| 17:36 | is like if this is like the office of the cell. So if |
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| 17:41 | making proteins in my rough endoplasm, , those proteins are gonna be found |
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| 17:47 | the endoplasm reticulum and you're gonna butt portions of the endoplasm reticulum in little |
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| 17:52 | vesicles and those vesicles are gonna be off to this structure. So these |
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| 17:58 | vess these little balls that you see been moved from the endoplasm curriculum and |
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| 18:03 | they're gonna do is they're gonna merge the Golgi and the go looks like |
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| 18:06 | series of pancakes stacked on each right? But they're big giant |
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| 18:11 | you can see the same sort of . Now, when we look at |
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| 18:14 | , you're like, ok, how does anything ever get done inside |
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| 18:17 | ? But again, part of this , it's so small that we don't |
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| 18:22 | all the reactions and all the But we do understand what it's trying |
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| 18:25 | accomplish and what it's doing is it's at those proteins and their organization, |
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| 18:32 | they're built and they're sorting them and where they need to go based upon |
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| 18:37 | that are part of the actual protein . So we receive on the side |
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| 18:44 | go with, into the cisterns, get tagged, modified sorted, moved |
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| 18:49 | and then depending upon what you, been sorted to do, you're actually |
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| 18:54 | to your destination. So some things going to stay inside vesicles and be |
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| 18:59 | . Some things are going to be into what are called lysosomes. And |
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| 19:04 | so those are going to stay inside cell and they're going to do their |
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| 19:06 | and we'll answer what lysosomes do in minute. If you're a, a |
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| 19:09 | that needs to be secreted, you're in a vesicle. And if you |
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| 19:12 | secreted immediately, you'll move up to plasma membrane and then you'll be released |
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| 19:16 | into the side or into the interstitial . If you're meant to be put |
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| 19:20 | the plasma membrane, you're sorted in different way and you're sent up as |
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| 19:24 | vesicle and you're moved to the plasma and you merge the plasma membrane. |
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| 19:29 | in essence, everything that you're doing is deciding the direction to which you |
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| 19:35 | supposed to go and it's not random proteins that are supposed to go in |
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| 19:39 | membrane, always go into the membrane that are supposed to be secreted are |
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| 19:42 | secreted, et cetera, et et cetera. The process is not |
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| 19:46 | understood yet, but it's what it . It's kind of like how does |
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| 19:50 | post office know how to send my ? Well, they have a scanning |
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| 19:53 | and things just happen. It's you know, now the opposite |
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| 19:59 | So if this is the side, the trans side, so the sending |
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| 20:02 | is the trans side. All So I mentioned the lysosome, that's |
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| 20:08 | of the destinations. One of the that a um um proteins can be |
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| 20:13 | to and this is a vesicle that formed from the goal. All |
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| 20:18 | So in this picture, this is the Liz, this is supposed to |
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| 20:22 | a cell, it's supposed to be , um, uh brain turned |
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| 20:29 | Hold on. Um, a That's what I'm looking for. |
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| 20:35 | All right. And its job is hunt around and look for things that |
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| 20:39 | supposed to be in your body like bacterium and it kind of goes around |
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| 20:43 | just sits there and goes, is supposed to be here? Is this |
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| 20:45 | to be here? And if I something that's not supposed to be |
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| 20:47 | what it does, it goes out out surrounds it and encases that foreign |
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| 20:54 | inside a vesicle? All right. , what we gotta do is we |
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| 20:58 | to destroy that and then it's made of all the little tiny things that |
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| 21:01 | body can use. So it's gonna down the materials. Well, how |
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| 21:05 | the cell break that down? that's the purpose of the lysosome. |
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| 21:10 | lysosome is an organelle that contains the enzymes to help break down materials and |
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| 21:17 | creates an environment that's incredibly acidic. so when you merge aly a zone |
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| 21:23 | the faga zone, which is basically a structure that you engulfed, |
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| 21:28 | So it's a vesicle that I've engulfed something in it. What's going to |
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| 21:31 | is I merge those two things The low P H creates the environment |
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| 21:35 | allow the enzymes to work. It up the thing that you've consumed and |
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| 21:40 | end up with all the little tiny and then you can do things with |
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| 21:43 | little tiny bits like recycle it. if it's amino acids or nucleic acids |
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| 21:47 | whatever, you can recycle them from cell because it doesn't matter where those |
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| 21:51 | come from, they're reusable, Think about the food you eat food |
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| 21:56 | eat are, are, is the thing that your body is made up |
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| 22:00 | lipids, fats, sugars. All . Now, what's interesting is the |
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| 22:06 | like the hydro laces. What can is you can then recycle them, |
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| 22:10 | can keep moving them and, and this process ongoing. Now you guys |
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| 22:18 | of an ulcer. What's an ulcer your body? Basically, the digestive |
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| 22:25 | of your stomach have worked their way the protective barriers of the stomach and |
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| 22:28 | now basically chewing through your stomach Right. It's not something that's really |
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| 22:33 | . It doesn't feel good. Not you want. All right. |
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| 22:39 | with a lysosome, if those enzymes not contained within that vesicle, they're |
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| 22:46 | gonna chew up what's ever inside the , right? Enzymes don't know how |
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| 22:51 | distinguish between self and nonself, They just know how to break down |
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| 22:56 | they're supposed to break down or to to, they're there to catalyze a |
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| 23:01 | , right? So if you in other words, if you break |
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| 23:06 | lyo zone, then those um those are just gonna start chewing up the |
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| 23:13 | that's inside the cell. This is , you're gonna, you have to |
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| 23:17 | with me autolysis. It's not it's autolysis. OK? Got |
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| 23:24 | Sounds fancy. Just get your cup tea, put your thumb out or |
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| 23:27 | pinky. I go it's autolysis. . Auto is a hot, hot |
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| 23:35 | to study right now. All So auto sounds a lot like |
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| 23:40 | Auto means self means to eat. this is self eating right? And |
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| 23:45 | sounds like, well, I'm self because it's, this is bad because |
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| 23:49 | something that went horribly wrong. Auto a cell's mechanism of trying to control |
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| 23:56 | process of destroying things that need to destroyed in the cell. So, |
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| 24:01 | of the ways that your body fights is through, ahoy. And when |
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| 24:06 | auto fails, the cell keeps going and on. Right. That would |
|
| 24:10 | an example. So here in auto like, oh, I've got something |
|
| 24:14 | broken inside the cell. I need get rid of it because it's gonna |
|
| 24:18 | problems. So the lysosome goes to broken organelle merges with it and tries |
|
| 24:24 | break it down in an organized All right, we're trying to understand |
|
| 24:28 | process because it's like, oh, another way to cure cancer and we'll |
|
| 24:31 | not. I'm just saying. All . So, so far we started |
|
| 24:38 | nucleus, nucleus to the endoplasm, endoplasm curriculum to the Golgi. We |
|
| 24:43 | at one thing breaking off the, is called the LYO. Now we're |
|
| 24:49 | at something that doesn't break off the , we're going all the way back |
|
| 24:52 | the ends curriculum and we're looking at pera. All right. And |
|
| 24:56 | a peri is a vesicle, It has within it, a bunch |
|
| 25:01 | enzymes. All right. Those enzymes both oxidase and catalas. So you |
|
| 25:07 | that A E at the end? what an oxidase does is, it |
|
| 25:11 | for things that are called free It's an antioxidant. That's what oxidation |
|
| 25:16 | . Do they, they play the of antioxidants? All right. |
|
| 25:20 | you probably don't know what a free is. Have you ever heard of |
|
| 25:22 | free radical. Yes. 11 23, maybe, right. Free |
|
| 25:27 | are basically molecular time bombs. what you've done is you've taken where |
|
| 25:32 | had two oxygens attached to one another they broke apart and they kept their |
|
| 25:37 | electron and that one electron is now of balance and it wants desperately to |
|
| 25:42 | another electron. So it's willing to bonds and create molecular chaos to |
|
| 25:48 | So it's a bad thing, And so what we have is we |
|
| 25:52 | a series of, of enzymes that responsible for reducing the dangers of the |
|
| 25:57 | radicals. All right, one of things that we, the reason we |
|
| 26:01 | vitamin C, it's an antioxidant. helps us to fight the free radicals |
|
| 26:05 | our bodies. It helps reduce the of bad things happening. So what |
|
| 26:10 | oxidase does is says, well, can't completely get rid of a free |
|
| 26:14 | , but I can make it into less dangerous free radical. And so |
|
| 26:17 | they do is that they convert these radicals into a molecule called you guys |
|
| 26:23 | what that molecule is. What is peroxide? So you know that's the |
|
| 26:29 | that you use to dye your you know, to put on a |
|
| 26:32 | and make it bubble, right? hydrogen peroxide. And that's the least |
|
| 26:38 | of the free radicals. And then we do is we have a catalyst |
|
| 26:41 | says, all right, I'm gonna the least dangerous of the free |
|
| 26:43 | I'm going to convert it into a free radical. What's that molecule? |
|
| 26:50 | ? So that's the job of the or the excuse me, the |
|
| 26:54 | I'm going to soak up and find dangerous molecules. I'm going to convert |
|
| 27:01 | , detoxify the environment, make it and less dangerous. And finally, |
|
| 27:06 | get to the point where I can make water. So you'll find these |
|
| 27:10 | a whole bunch of different places. the process of of breaking down fatty |
|
| 27:14 | is called be oxidation. That's where see uh proxim and cells that play |
|
| 27:17 | role in that, you'll see it in hepatocytes. Hepatocytes are liver |
|
| 27:23 | You guys have learned that your liver for dealing with toxic things, |
|
| 27:27 | At some point. Yeah. So it. And then we've already mentioned |
|
| 27:30 | . All right. Now, the thing is that they don't arise from |
|
| 27:34 | , like I said, they arise the endoplasm curriculum and what they'll also |
|
| 27:38 | is you'll take two small xom, come together and form a larger |
|
| 27:42 | So that's this process of fission that gonna be doing. They self arise |
|
| 27:46 | kind of create themselves. All So this is kind of the weird |
|
| 27:51 | , it sets out which we had mention it because it's still in a |
|
| 27:54 | , kind of like a lysosome is shifting away from kind of this pathway |
|
| 28:00 | the Golgi and we're dealing with the structure in the human cell, which |
|
| 28:06 | the mitochondria. Now, in very terms, mitochondria is responsible for making |
|
| 28:10 | . All right, it is the that makes a T P or not |
|
| 28:14 | cell, it is a structure in A T P is primarily made. |
|
| 28:18 | whenever you're dealing with uh any sort aerobic cellular activity, so anything that |
|
| 28:24 | oxygen, so your cells make more T P with oxygen, they make |
|
| 28:28 | A T P without oxygen. This the uh the structure that's playing the |
|
| 28:33 | . Now, what's interesting about this that the mitochondria has its own DNA |
|
| 28:39 | its own R N A can replicate . So if the cell needs more |
|
| 28:43 | , it will actually the mitochondria themselves actually replicate and make more of |
|
| 28:49 | The mitochondria was a cell swallowed by cell. That's why it has its |
|
| 28:55 | DNA. It stuck around for some , the cell didn't destroy it but |
|
| 29:01 | this structure inside a vesicle and it existed with all eukaryotic cells for as |
|
| 29:09 | as we can remember. All So it's one of these weird things |
|
| 29:14 | it's not part of the actual cell . It was something that's been passed |
|
| 29:20 | during this process of cell division over over again. So think of it |
|
| 29:25 | of like a parasite that stuck around SIM. It would be a better |
|
| 29:29 | . Um So if you look in that require lots of energy like muscle |
|
| 29:35 | , you're gonna see lots of Oh And by the way, uh |
|
| 29:38 | mitochondria primarily and I'm saying primarily we say it does come from, but |
|
| 29:42 | some evidence that all come from your . All right. So everyone has |
|
| 29:49 | mitochondria that your mother gave you. that's one of the ways we can |
|
| 29:53 | lineage is through maternal mitochondrial DNA. mitochondria energy producers. Alright. Is |
|
| 30:05 | ribosome a membrane bound or, or molecular complex? What do we |
|
| 30:12 | Biomolecular? All right. So this a an organelle but it's not membrane |
|
| 30:18 | . Everything else that we looked at this backwards has so far been a |
|
| 30:24 | brown organelle. Here we have this molecular complex. It's basically a bunch |
|
| 30:29 | proteins and some R N A. right. And it creates these two |
|
| 30:35 | . We have what is called the subunit and the large subunit. And |
|
| 30:40 | these two things come together and allow to read a strand of messenger R |
|
| 30:46 | A so that you can make So you can see here's the growing |
|
| 30:50 | . All right. So, ribosomes ribosomes are responsible for protein synthesis. |
|
| 30:58 | right. That's, that's the key to take away from this. |
|
| 31:04 | you can find ribosomes in a bunch different areas. We've already looked at |
|
| 31:07 | endoplasm curriculum and we said, when I look in the microscope, |
|
| 31:10 | looks all bumpy, right. This an electron micrograph. You can see |
|
| 31:13 | the little dots, the little dots the ribosomes and that's on the surface |
|
| 31:18 | the endoplasm Curti. So this would what we refer to as a bound |
|
| 31:25 | . All right, its job is make proteins to help synthesize proteins that |
|
| 31:30 | be secreted or uh or uh put a vesicle or store or you |
|
| 31:35 | found in the surface of the cell the plat of a membrane. The |
|
| 31:39 | type of ribosome is what is called free ribosome. These are floating around |
|
| 31:44 | the cytozole. They might actually be in the mitochondria because the mitochondria can |
|
| 31:49 | um make its own proteins as well remember it has its own DNA and |
|
| 31:52 | own R N A. You can between these two points. You can |
|
| 31:57 | a free ribosome floating around the side all do your business there. And |
|
| 32:01 | after you've done your business, you go and pick up something and be |
|
| 32:04 | of a bound ribosome, ribosomes are confined to one area or the |
|
| 32:08 | They have free roam to where they're . All right. Now, what |
|
| 32:13 | looking at in this picture up all the big dots. Those are |
|
| 32:16 | ribosomes, those things that are going the, the ends, that's the |
|
| 32:20 | peptide and this chain that sits in middle, that's the M R N |
|
| 32:26 | that it's reading. OK. So protein synthesis does this feel like we're |
|
| 32:37 | faster, all this stuff or is like, OK, this is good |
|
| 32:39 | pace? Oh OK. People on back. OK. I'll, I'll |
|
| 32:46 | the one thumb up that, you , you're now representing the, |
|
| 32:50 | the back of the room. All right. So with those in |
|
| 32:55 | , what I wanna do is I keep in these uh these uh molecular |
|
| 33:00 | , bio molecular complexes. I wanna at the cytoskeleton, cytoskeleton literally means |
|
| 33:05 | skeleton. All right. But that's their only role they can serve kind |
|
| 33:09 | as the musculature of the cell as . So if you're trying to make |
|
| 33:14 | you know, you know, like or you know, whatever it's like |
|
| 33:20 | lysosome, it is kind of like stomach of the cell. The nucleus |
|
| 33:23 | kind of like the brain of the . The cytoskeleton needs the musculoskeletal system |
|
| 33:28 | the cell. All right. That's of how you can think about |
|
| 33:34 | And what we have is we have series of fibers that are going to |
|
| 33:38 | throughout the cytoplasm. So here you see what we've done. We've taken |
|
| 33:42 | cell, like here's a membrane, a membrane you can see here's the |
|
| 33:46 | , you can see in there. would that one be with the little |
|
| 33:50 | rough? Er, but you can here, I've got fibers and I |
|
| 33:55 | tubes and I got tubes and there's tube. Those would be examples. |
|
| 33:59 | And I, I guess the other stuff right there, those would be |
|
| 34:01 | filaments. We have these, these of tubes and, and filaments and |
|
| 34:08 | that are gonna penetrate throughout the cell create this network on which all these |
|
| 34:15 | , all these organelles are gonna be . In other words, when you |
|
| 34:20 | about the cell, it's not just bag of fluid with things floating in |
|
| 34:24 | . All these uh these cells have them, this massive network of these |
|
| 34:31 | and fibers and tubules that help to the cell arranged in the way that |
|
| 34:38 | needs to be arranged. Remember what said about epithelium, one of its |
|
| 34:42 | , what it, what was one the characteristics of epithelium? It had |
|
| 34:45 | word and start with A P and it with A Y it polarity. |
|
| 34:54 | right. And polarity means that you the two sides are different from each |
|
| 34:58 | . Right? Part of the reason you have polarity in the epithelial cell |
|
| 35:02 | because of this network. So it that on one side of the |
|
| 35:07 | it needs to have things to sin to receive and on the other |
|
| 35:10 | it has other structures and it's, it's defined because the presence of this |
|
| 35:16 | of skeleton, all right. So have this network of fibers. They |
|
| 35:22 | to maintain the shape of the cell to help to create the structures where |
|
| 35:28 | belong, helps to position, the , some cells are going to play |
|
| 35:31 | role in movement. I'm not sure ones allow me to move, which |
|
| 35:41 | . Thank you. I mean, know it took a while to think |
|
| 35:44 | that thing. I have them All right, they're gonna service kind |
|
| 35:52 | like highways in some cases and we're see these things called motor proteins. |
|
| 35:57 | fact, um, on canvas this , I posted a video that's, |
|
| 36:01 | like three minutes. It's, it's youtube video. There's actually, it's |
|
| 36:04 | shorter version of a longer one that is an imagination of what the inside |
|
| 36:09 | the cell looks like. Um uh these structures that we're talking about. |
|
| 36:14 | if you want to kind of see of a visual representation of a cell |
|
| 36:17 | action, you can kind of watch and see if you can identify the |
|
| 36:21 | structures in there. You know, , three minutes of your life, |
|
| 36:24 | not going to be on the but it kind of helps you visualize |
|
| 36:27 | much of the stuff that we're looking here is s itsy bitsy, teeny |
|
| 36:30 | , we usually see it like a and it's static, so we don't |
|
| 36:33 | it in action. All right. the three types of fibers we're gonna |
|
| 36:37 | looking at, they're right here at intermediate filament, the microtubule and the |
|
| 36:41 | and we're just gonna go through them one by one. And so what's |
|
| 36:45 | good about these pictures here is they're immunofluorescence so that we can look inside |
|
| 36:51 | cell. All right. Now, is a technique of using antibodies tagged |
|
| 36:57 | a fluorescent dye. And then what do is it tags, whatever it |
|
| 37:00 | that you can, you know that recognizes and then you hit it with |
|
| 37:03 | light at a, at a specific and it allows you to see what |
|
| 37:07 | tagged. And then what you can is you can assign a color to |
|
| 37:12 | tag. It's not really this They just basically allows you, you |
|
| 37:16 | digitize it. And then what you do is you can kind of see |
|
| 37:19 | these different things overlay on each So like the blue here is something |
|
| 37:23 | tags uh DNA. And so you where the nucleus of the individual cells |
|
| 37:28 | , right? And then you can the green is tagging something and you |
|
| 37:31 | the red is tagging something and the here is actually tagging micro filaments. |
|
| 37:37 | just to help you know, that what we're talking about. The microfilament |
|
| 37:41 | down here in red so that you see that's what we're looking at. |
|
| 37:44 | in looking at this picture here, can see there's a lot of microfilament |
|
| 37:48 | this cell and you can see where boundary of the cell is. It |
|
| 37:52 | of sits like that, right? not 100% accurate, but you can |
|
| 37:55 | of get a sense. So, do you see these micro filaments primarily |
|
| 37:59 | the edges of the cell? what do microfilament primarily do? |
|
| 38:04 | they play an important role in bearing . All right, I'm gonna use |
|
| 38:11 | for a second. Give me your , pull against me, pull against |
|
| 38:17 | . That's what cells are doing all time. They're fighting each other. |
|
| 38:21 | not really fighting each other, but basically bearing each other's tension. |
|
| 38:24 | again, if we're doing this and pulls on me, he has something |
|
| 38:29 | pull against. Right. It's oh, I'm resisting the pull this |
|
| 38:33 | and there's something behind you and they're tension. How many of you guys |
|
| 38:38 | an older sibling? How many of guys got an Indian burn from your |
|
| 38:42 | , older sibling? You know what Indian burn is? Some people are |
|
| 38:45 | at me like, I don't it's when they go up to you |
|
| 38:47 | like, you know, grab your or you have your arm. |
|
| 38:49 | I wouldn't do this. You go this and you're like, ah, |
|
| 38:54 | you're like, ah, and why the skin doesn't come falling off? |
|
| 38:58 | . Because if I twist the why does it come rolling off? |
|
| 39:01 | reason is because of these micro filaments tension to prevent the cells when you |
|
| 39:08 | on one, you're pulling on all cells and vice versa. So it |
|
| 39:13 | this tension against each other. what is a microfilament, microfilament is |
|
| 39:19 | a series of these little tiny Each of these little balls is an |
|
| 39:23 | molecule of acting. And what they is this, this act in pairs |
|
| 39:28 | with other acting and you create these chains and the long chains by themselves |
|
| 39:33 | like hanging out by themselves. And what they do is they find another |
|
| 39:36 | chain and you create this massive And so now what you have is |
|
| 39:41 | have a rope of or a filament acting molecules. That's a microfilament. |
|
| 39:47 | right. Now, this helps to the shape of a cell. So |
|
| 39:54 | gonna see cells. Each cell has own unique shape and its own behavior |
|
| 39:58 | a function of these micro ments, play a major role in movement. |
|
| 40:03 | gonna talk about muscles. You've if you've again taking any sort of |
|
| 40:07 | science class, they probably talked about and muscles have two fibers. They |
|
| 40:11 | uh thick filaments and thin filaments. thin filaments are acting molecules plus some |
|
| 40:17 | stuff. The thick filaments are my my act and work with each other |
|
| 40:23 | they are what creates the contraction in muscle. Um Let's see what else |
|
| 40:31 | have here. Oh Yeah. So can have cell contraction, you can |
|
| 40:35 | localized contraction. So you basically can kind of some unique stuff. The |
|
| 40:39 | thing is cytokinesis. If you had guess what that word means, what |
|
| 40:43 | it mean, cytokinesis trying to make brains think about. By the |
|
| 40:48 | you're learning a new language. I'm letting you know biology, just like |
|
| 40:53 | is a new language. It's just language is a little bit easier because |
|
| 40:56 | have like I said, slashes and and horrible things. What is |
|
| 41:02 | Cyto is so kinesis movement, cell , right? Do you know your |
|
| 41:10 | ? There are some cells in your that move around, right? That |
|
| 41:14 | around that literally travel between the other , right? Your immune cells do |
|
| 41:21 | , right? They're on patrol looking things that are trying desperately to kill |
|
| 41:26 | . Actually, they're not trying to you, they just happen to kill |
|
| 41:29 | . You know, so you have blood cells that are circulating in, |
|
| 41:33 | will move and weave their way around we talked about those faga sites, |
|
| 41:38 | ? What are they doing? They're around looking for things to destroy and |
|
| 41:42 | need to move and the way they is with acting filaments changing the shape |
|
| 41:50 | the cell so that they can roll obviously a different picture than the one |
|
| 41:58 | here, we have the intermediate filaments . What do you suppose in that |
|
| 42:01 | old black circle in the middle? do you suppose is sitting in there |
|
| 42:07 | ? Right? And so you can is this a network, does this |
|
| 42:11 | like there is structure to this cell being arranged through these intermediate filaments. |
|
| 42:16 | of, sort of, yeah. right. Now, there are lots |
|
| 42:19 | different types of intermediate filaments. The that we uh spend a lot of |
|
| 42:23 | talking about are those that are members the carrot family. Carrot is what |
|
| 42:28 | up your nails and your hair and found in your skin. So this |
|
| 42:32 | why we spend a lot of time about it because it's something that's a |
|
| 42:35 | bit more familiar to us. if you hit your fingernail, it's |
|
| 42:38 | of kind of hard, isn't So Carotin is kind of a resistant |
|
| 42:44 | , right? There's not a lot give to it. Its job again |
|
| 42:47 | to resist uh tension. Um Unlike , you know, our micro |
|
| 42:54 | intermediate filaments are more permanent. What see with these is that you'll build |
|
| 42:59 | and break them down with some degree frequency here. What they do is |
|
| 43:02 | kind of more or less stick So once you build it, it's |
|
| 43:05 | permanently for the most part. All , their job again is to stabilize |
|
| 43:11 | cell to create a strength to the . And then we're back to our |
|
| 43:17 | picture again. So again, you see the red, that was our |
|
| 43:20 | and the blue, there's a the green is the microtubule. Now |
|
| 43:25 | here it has a micro, small tells you that it has a tubular |
|
| 43:30 | or tubular structure. And what you're is you have this protein called tubulin |
|
| 43:34 | that clever. That's how, that's biologists name the stuff it's like, |
|
| 43:38 | , well, it forms a So let's just call it the tube |
|
| 43:42 | . So, tubulin, all And so what you have here is |
|
| 43:45 | got these tubulin molecules, they form dim and then what they do is |
|
| 43:49 | arrange themselves and they just kind of this helix that ultimately forms a |
|
| 43:53 | And so if you look, you kind of see there's the tube that |
|
| 43:55 | through there. Right now, these are formed from a, from a |
|
| 44:02 | a bio molecular complex called the And in the centro zone, we're |
|
| 44:07 | see centris from which they're derived and the things that create resistance in the |
|
| 44:13 | so that you can't squish it. right. So whereas acting prevents you |
|
| 44:17 | pulling the cell apart. Tubulin. these uh microtubules serve kind of as |
|
| 44:23 | for compression. All right, they serve on track as tracks through which |
|
| 44:28 | proteins can move, which we'll see a second. Um We're gonna talk |
|
| 44:32 | tomorrow about pilum flagella, they make the inner workings of cilium flagella. |
|
| 44:38 | And so allow for movement in that . Um They play an important role |
|
| 44:43 | cell division in terms of breaking apart the the uh paired chromosomes so into |
|
| 44:50 | daughter cells, right? So they multiple functions. All right. |
|
| 44:56 | again, these are not permanent They build them as you need them |
|
| 45:00 | you break them down as quickly as as you don't need them. So |
|
| 45:03 | , they're, they're pretty dynamic in of their presence. That's what all |
|
| 45:08 | green stuff is, is trying to you um where microtubules would be in |
|
| 45:13 | particular cell. So this is a zone and I should pause here. |
|
| 45:20 | mean, we've just introduced three different . So do you kind of see |
|
| 45:24 | differences between the three different types of skeletal elements? The the larger |
|
| 45:29 | these are families. So there are more structures and more structures underneath |
|
| 45:34 | But microfilament pretty straightforward, intermediate, kind of straightforward microbial, straightforward. |
|
| 45:39 | . So we introduced the centrosome here it kind of extends off the idea |
|
| 45:44 | the microtubule. All right. So centrosome is an area or a site |
|
| 45:50 | which microtubules actually are formed and it like this. There are actually two |
|
| 45:56 | in there called centris. And that's those two things are actually one's called |
|
| 46:00 | mother, one's called the daughter and actually connected to each other. You |
|
| 46:06 | see here the little white, little that the artist put in there and |
|
| 46:11 | them is kind of this cloud of , all right. So this is |
|
| 46:16 | which all microtubules originate. And so can see the tubes at the end |
|
| 46:21 | is where the microtubules come from. have their very specific structure to |
|
| 46:26 | This nine plus two structure, which , if you count these up, |
|
| 46:32 | are triplets right now. So, . So that's what a cental |
|
| 46:40 | But the microtubules will extend and then end up like going into the, |
|
| 46:45 | , or the, and they'll have nine and then they'll have two on |
|
| 46:49 | inside. And so it's, it's way of organization. All right. |
|
| 46:54 | , when I was in school, called uh these structures, these |
|
| 47:00 | they called them basal bodies. They're same thing. All right. And |
|
| 47:04 | you might see, um, those kind of flipped if you have an |
|
| 47:09 | professor, you know, or something those lines, right? But |
|
| 47:14 | this is where all that energy goes . So remember if we're compressing that |
|
| 47:20 | , you know, so I'm gonna him again. Let's push against each |
|
| 47:24 | . So push, right. Where that force go? I mean, |
|
| 47:27 | on a wheel. So it's, does that force go? It goes |
|
| 47:30 | his center core. Right. that's where that, that force |
|
| 47:35 | Well, the force and compression would here and then it's distributed back out |
|
| 47:41 | , along those lines again to where it's being distributed to the next cell |
|
| 47:46 | the next cell and the next All right. So this is how |
|
| 47:50 | resists the compression so far. So . All right. What are little |
|
| 48:06 | made of? There you go and nice what we're looking at and the |
|
| 48:17 | I bring that up because we we're moving out of the cell for |
|
| 48:21 | moment. All right, we focused the nucleus. Made it pretty |
|
| 48:25 | Keeping it simple. Um, who a biology major? Just all |
|
| 48:30 | So you guys get to take cell . That's the required class. You'll |
|
| 48:34 | it in your, in your, your senior year, if not your |
|
| 48:36 | year and you go deep dive into structures, right? So you'll go |
|
| 48:42 | a lot greater detail than what we're . All right, we did the |
|
| 48:49 | , we've gone through the organelles and we're coming out to the plasma |
|
| 48:54 | The plasma membrane remember is a phospho bilayer, right? Remember what we |
|
| 48:59 | about phospho lipids. They have a head, they have a nonpolar |
|
| 49:04 | the nonpolar tail is excluded by the . So it faces away from |
|
| 49:08 | And so what we're doing is we're a protective environment for those non polar |
|
| 49:13 | . And so we have a portion faces water, this direction, portion |
|
| 49:17 | faces water, that direction. And we do is we create a |
|
| 49:21 | All right, that's the purpose of plasma membrane. Now, there are |
|
| 49:25 | than just fossil lipids inside the plasma . There's a bunch of different |
|
| 49:31 | So we're gonna see a couple of different lipids, right? We'll see |
|
| 49:36 | like um cholesterol, right? That's the artist is trying to show here |
|
| 49:41 | cholesterol, right? We'll see free acids because free fatty acids are gonna |
|
| 49:46 | just as excluded. So, a acid would be just like this tail |
|
| 49:51 | here. It just doesn't have the portion, doesn't have the glycerol. |
|
| 49:54 | so it's sitting around going water, me. So, where can I |
|
| 49:57 | ? Well, this is a good for it to go. It can |
|
| 50:00 | of work its way into there. then the other thing that we're gonna |
|
| 50:03 | , we're gonna see the glyco we mentioned them, right? We |
|
| 50:06 | these are sugars onto which have they've been attached to fats, |
|
| 50:13 | So um this green thing right they're trying to demonstrate this as a |
|
| 50:18 | lipids. So you can see the acid tail and you can see that's |
|
| 50:22 | sugar extending off to the edge. right. So there are different types |
|
| 50:28 | lipids that can be found here. the primary lipid that you can see |
|
| 50:31 | the pilot membrane is gonna be the lipid. And notice here that when |
|
| 50:36 | talking about the glycolipid, which direction it facing? It's always facing |
|
| 50:42 | right? It never faces inward. sugars are always pointing outward, |
|
| 50:48 | Because candy tastes better. When the is pointing outward, there are different |
|
| 50:54 | of proteins and these are not specific terms of functionality but how they're associated |
|
| 51:00 | the membrane, right? We have proteins, integrated proteins or integral proteins |
|
| 51:05 | those proteins that are pushing through the membrane, right. They've been integrated |
|
| 51:14 | the membrane, they're part of the . So you'll find them sticking out |
|
| 51:19 | least one side, but usually both . All right. And then we'll |
|
| 51:24 | proteins. And this is not a example of a peripheral protein. Usually |
|
| 51:28 | they a peripheral protein is is they be associated near to an integral |
|
| 51:34 | So they might be associated with it are uh kind of associated on the |
|
| 51:39 | here like to a membrane. So is trying to say it's been |
|
| 51:43 | but by definition, that would be . So the artist did a terrible |
|
| 51:47 | in this particular case. So peripheral are found on the periphery, right |
|
| 51:55 | of makes sense. Integrated pro proteins integrated into periphery proteins are found on |
|
| 52:00 | outside proteins that have sugars attached to are called glyco proteins. So here |
|
| 52:07 | can see glycoprotein notice the direction. there any glycoprotein down on this |
|
| 52:12 | No, because sugars always point All right. So the glycoprotein you're |
|
| 52:17 | see are just proteins that have the modi modi being the sugar um marker |
|
| 52:23 | sits on the outside. Now, molecules are not fixed in place. |
|
| 52:31 | right, they're, they're movable, not attached to each other. All |
|
| 52:36 | , what they have is they have that allow them to associate. We |
|
| 52:41 | about the phospho lipid phospho lipid has charged head. So it points towards |
|
| 52:45 | , the tail is non charged, ? So it's excluded from water. |
|
| 52:50 | this is gonna be true for the protein. So this region here of |
|
| 52:55 | protein is excluded from water. It's attracted to the environment that the nonpolar |
|
| 53:03 | are attracted to the regions that are out on either side, like those |
|
| 53:09 | charged or are associated or affiliated with . They are attracted to the |
|
| 53:14 | So that's why they're associated the way are. Remember when we talk about |
|
| 53:18 | amino acids, I said, here's big chart of 20 amino acids that |
|
| 53:21 | don't need to memorize, but they're together. And we have those variable |
|
| 53:25 | that have all these different characteristics. variable groups are the things that create |
|
| 53:31 | those proteins are going to be All right. So if they have |
|
| 53:36 | regions out on the outside, non region is going to be on the |
|
| 53:40 | , right? But they're not attached each other. So what that means |
|
| 53:45 | , is if you're this little you're basically kind of floating around going |
|
| 53:49 | . How you doing? You you're just moving around saying hi to |
|
| 53:52 | they can move within their side of layer as much as they want |
|
| 53:58 | right? Because they're freely mobile, proteins are not fixed in place unless |
|
| 54:03 | attached to the cytoskeleton. You can here we've got some cytoskeleton down |
|
| 54:07 | some of them might be attached, they're free to move around as well |
|
| 54:13 | they have that freedom of mobility. is no direct association. I worked |
|
| 54:17 | a lab at MD Anderson next door a lab that worked on proteins in |
|
| 54:21 | membrane. And what they, and , and what they were looking at |
|
| 54:24 | they're looking at their mobility and they're these were kind of these immune cells |
|
| 54:28 | kind of wandered around and stuff, wanted to see how well they wandered |
|
| 54:32 | in space. And so they hit up with these immuno fluorescent proteins that |
|
| 54:35 | described earlier and they would film And it was interesting because you'd see |
|
| 54:40 | they attach themselves to the plate because growing them in, in plates, |
|
| 54:46 | ? The the proteins would fix and when that cell would walk away, |
|
| 54:50 | protein that was attached to the plate then like sprint around the top of |
|
| 54:54 | cell and then go to the other , you know, kind of like |
|
| 54:57 | trunk or tank tread, right? that's just a, a really good |
|
| 55:03 | , a visual demonstration of what these are capable of doing. They just |
|
| 55:07 | based upon their need, right? where they should be associated. All |
|
| 55:15 | . So what we refer to this freedom of movement and this ability |
|
| 55:19 | things to move around is called the mosaic model fluid. Because the things |
|
| 55:24 | go wherever they want to go meaning because there's no rhyme or reason |
|
| 55:29 | to how these things are arranged, , they create this mosaic or unique |
|
| 55:35 | . Now, it's very, very , but it's possible for a lipid |
|
| 55:42 | flip from one side to the But usually this is a bad |
|
| 55:46 | It's usually an enzyme that's required. it costs a lot of energy and |
|
| 55:50 | actually a tool that we can use look for cells that are misbehaving. |
|
| 55:54 | we put it in there, we see these proteins or lipids flipping |
|
| 56:01 | So your membranes are fluid. But you fluid? Are you, are |
|
| 56:06 | like jelly? Are you like No. Right. If you've cooked |
|
| 56:15 | , have you all cooked before you've butter and stuck it in a |
|
| 56:18 | What happens to that, that hard of butter, that solid. When |
|
| 56:21 | put it on heat, it it goes from the fat to the |
|
| 56:27 | , doesn't it? Right. guess what? You're made up of |
|
| 56:32 | . If we put enough heat on , what are you gonna turn into |
|
| 56:36 | ? All right. And we live Houston. So it's a greater chance |
|
| 56:40 | us turning into oil pretty quickly right . If you live up in the |
|
| 56:44 | , like, like closer and closer the pole where it's got colder |
|
| 56:48 | you'd expect that cells would become more a fat, right? They'd become |
|
| 56:52 | solid that this is what's kind of on the way that you can think |
|
| 56:57 | this is and we don't always think this, but temperature is a, |
|
| 57:02 | measure of kinetic energy, right? much are the molecules moving, the |
|
| 57:08 | it is the greater the kinetic the more molecules move around? Do |
|
| 57:12 | remember that from life? What was , what was it before? Life |
|
| 57:15 | ? In, in like ninth it was like earth science or like |
|
| 57:18 | like a general science class. Do remember taking that way back when? |
|
| 57:23 | they kind of talk about steam versus and stuff like that? And it's |
|
| 57:27 | the molecules bouncing around, the more you add, the more molecules bounce |
|
| 57:32 | . And that's true. It doesn't if you're looking at water molecules or |
|
| 57:36 | you're looking at fat molecules in an where I have more heat, those |
|
| 57:41 | are bouncing into each other and they're themselves more elbow room. So you |
|
| 57:44 | more of that liquid state and in environments, those those molecules have less |
|
| 57:50 | energy so that you have less elbow . So they kind of scrunch up |
|
| 57:54 | and they become more solid. if you can't visualize this, I |
|
| 57:57 | you to go home and I want to pull out that, that a |
|
| 58:01 | of country croc that you have hiding the fridge and I want you to |
|
| 58:05 | it out on the counter for about hour and a half. Let that |
|
| 58:07 | warm up to room temperature and look there and tell me if you see |
|
| 58:10 | solid anymore because all that is is that has been driven down to |
|
| 58:17 | to a temperature that allows it to . And then you'll think about re |
|
| 58:22 | that country croc. You're like, is just oil. I, so |
|
| 58:29 | is a problem for yourselves, So how does ourselves overcome this? |
|
| 58:37 | , first off, we talked about and unsaturated, right? So here |
|
| 58:42 | have saturated, we said they can up really, really close together. |
|
| 58:45 | that's going to create a very, solid plasma membrane, but that's not |
|
| 58:50 | a good thing, right? In environments, that means things aren't going |
|
| 58:54 | be able to move back and forth the membrane. So what we do |
|
| 58:59 | inserted within the membrane, our s are uh unsaturated bonds, right? |
|
| 59:07 | fats. And what that does is most of the cell or most of |
|
| 59:11 | fats are gonna be kind of close every now and then you've got one |
|
| 59:14 | those fats that has a kink in . So it doesn't allow a fat |
|
| 59:17 | come in. So that creates kind a looser environment. All right. |
|
| 59:23 | at colder temperatures, I have a that can still remain kind of fluid |
|
| 59:30 | of the presence of these unsaturated That kind of makes sense. In |
|
| 59:35 | words, the colder you get, more solid you're gonna get. But |
|
| 59:37 | I have things that can't get close , I'm gonna stay kind of in |
|
| 59:41 | fluid state. So that allows us , to deal with cooler temperatures, |
|
| 59:48 | of cool. All right. But about these warmer temperatures? Right. |
|
| 59:51 | mean, everything is gonna be moving and, oh my goodness, you're |
|
| 59:54 | those unsaturated bonds. There's gonna be lot more space. So we're gonna |
|
| 59:58 | into liquid and we're gonna melt and it's just gonna be like the wicked |
|
| 60:00 | of the West at the end of Wizard of Oz. Uh Well, |
|
| 60:05 | we said there's more than fossil lipids are in the membrane. We have |
|
| 60:08 | like cholesterol and what cholesterol does is sneaks in to those gaps between the |
|
| 60:14 | lipids. One because it's a fat it wants to hang out with other |
|
| 60:19 | . But two because there's space for . And so when cholesterol works its |
|
| 60:23 | into the the gaps, it creates in those liquidy environments. And so |
|
| 60:31 | gives us resistance to higher temperatures. we remain more like a solid membrane |
|
| 60:38 | higher temperatures. So that gives our this ability to have this broader range |
|
| 60:44 | survival in higher and lower temperatures. of cool. Huh? You're |
|
| 60:52 | I don't care. All right. are little girls made of sugar and |
|
| 60:58 | ? Well, so are boys because all have a Glyco Calix, |
|
| 61:03 | The Glyco Cali is simply the sum all the different glycolipid and glycoprotein and |
|
| 61:10 | sugars that are found on the extracellular . The glycolic serves as a mechanism |
|
| 61:17 | cells to recognize other cells or your to recognize self versus non self. |
|
| 61:23 | giving ourselves basically a candy coating that this cell belongs here and everyone's glycolic |
|
| 61:32 | completely different from other people's. So just a mechanism of tagging self versus |
|
| 61:38 | self. Now, why do we about all this stuff? What is |
|
| 61:41 | whole function of this plasma membrane? right. Well, first off what |
|
| 61:46 | done is we've created a physical barrier water soluble substances. All right. |
|
| 61:53 | here, water is there. That the things that are floating in here |
|
| 61:57 | pass through the nonwater environment, If I have a charge, I'm |
|
| 62:02 | to this, I'm not attracted to . So I can't move through. |
|
| 62:08 | I've created a barrier to create a environment between the two points. So |
|
| 62:13 | outside of the cell is going to different from the inside of the |
|
| 62:16 | All right. The second thing I is I can create a selectively permeable |
|
| 62:22 | . I can insert into this plasma , a series of proteins like a |
|
| 62:28 | . And I can say I'm going allow you to come through the channels |
|
| 62:34 | specific. So they're going to identify one thing to allow them to come |
|
| 62:39 | . If I have a carrier, may be able to pick up one |
|
| 62:42 | like a glucose molecule and say you're allowed to come in. But |
|
| 62:47 | acid over there, I'm not interested you coming in, you have to |
|
| 62:49 | your own doorway. So I get choose what moves in and out of |
|
| 62:53 | barrier just like you get to do home. Think about your house. |
|
| 62:57 | is at the front of your A door, someone comes and knocks |
|
| 63:02 | the door, you can peek out say, am I going to let |
|
| 63:05 | in? It is a selective barrier what allows you to come in and |
|
| 63:09 | . If you take the door out its frame, anything can go in |
|
| 63:12 | out of the house, raccoons, , uh homeless people, your your |
|
| 63:17 | from next door, right? They'll up at the wrong time. So |
|
| 63:22 | we have is we have a mechanism controlling what moves it out in |
|
| 63:27 | So by controlling what moves in and specifically because of the presence of ions |
|
| 63:32 | how those ions are affiliated. What can do is we can create this |
|
| 63:36 | chemical gradient. So there's a difference the inside and a difference on the |
|
| 63:41 | . Whenever there's a gradient, that I have the potential to move more |
|
| 63:45 | less ions. And it's this electrical gradient that allows me to do unique |
|
| 63:53 | . This is what allows your muscles contract your neurons to communicate. So |
|
| 63:58 | created an environment to control through the permeability. Lastly, because we're making |
|
| 64:08 | different from that and we're keeping them , we can insert other molecules that |
|
| 64:14 | communicate between those two environments, These are like receptors. And so |
|
| 64:19 | can have a molecule come along bind this, which causes a change in |
|
| 64:23 | shape of this molecule which then communicates another molecule and tells this cell what |
|
| 64:27 | do without interrupting its unique environment. the plasma membrane isn't just a |
|
| 64:35 | it's a way of communication and a of regulation regulating the things that are |
|
| 64:40 | inside the cell. When I sat your seat, I thought the cell |
|
| 64:45 | was the single most boring thing on planet. And I got invited after |
|
| 64:50 | earned my phd to go work with on the plasma membrane. I said |
|
| 64:54 | , I couldn't, I didn't have heart trouble most boring subject ever. |
|
| 64:58 | the more I teach about the plasma , the more I'm like, oh |
|
| 65:01 | is what one of the most important you can ever learn about. And |
|
| 65:04 | not saying treat it like that. understand it's not just like I'm telling |
|
| 65:08 | this stuff because it's like it's actually kind of important. So a plasma |
|
| 65:16 | , does that make sense? Are good with what it is? What |
|
| 65:18 | does? We're going to come back the plasma membrane over and over and |
|
| 65:22 | again and you're going to get tired seeing it I'm just, I'm just |
|
| 65:25 | you know now, but it's because it, your cells wouldn't function the |
|
| 65:29 | that they. Do. You guys this slide? Yes. How are |
|
| 65:34 | doing on time? Oh, we're real good. It's been an |
|
| 65:37 | How are we doing? All So remember this slide, what we |
|
| 65:42 | said is, look, um when dealing with hereditary material genetics, uh |
|
| 65:47 | is transcribed and we're gonna, we're slow down on the word here, |
|
| 65:52 | into R N A R N A then translated into a functional protein. |
|
| 65:57 | a protein that does the work in cell. Now, if you've taken |
|
| 66:00 | biology, you've learned that there are like things like retroviruses, they don't |
|
| 66:05 | the central dogma. But this is how every cell on the planet |
|
| 66:10 | right. DNA? To R N R N A to protein proteins do |
|
| 66:13 | work, right? And so what wanna do is we wanna understand this |
|
| 66:18 | a little bit more um today than did yesterday. All right. So |
|
| 66:23 | understand what these words mean, We said what they were structurally, |
|
| 66:26 | DNA is. We said structurally what N A is. But let's really |
|
| 66:30 | of dive in DNA contains genes, are sequences of, of nucleotides that |
|
| 66:39 | instruction sets to tell your cell what of proteins to make. And in |
|
| 66:45 | sequence there is DNA that's useful for that protein. And then there is |
|
| 66:51 | in that sequence that is not useful making that protein. Now, that |
|
| 66:55 | mean that it's unuseful DNA. It's for that particular protein, right? |
|
| 66:59 | refer to these sequences as exxons and . So if it's for making that |
|
| 67:04 | , that is an Exxon, if not for making the protein, it's |
|
| 67:07 | Enron, those words come from intervening and Exxon, I can't remember. |
|
| 67:12 | excised, I think is how it's again. If you've taken any sort |
|
| 67:18 | biology classes, um you've probably learned there's more R N A s than |
|
| 67:22 | can probably count. I think in office, I have a poster that |
|
| 67:25 | something like 30 some odd different types R N A s, but we |
|
| 67:29 | have to know them all. We need to know these. All |
|
| 67:32 | So there are three basic types of N A s that play a role |
|
| 67:35 | proteins. Sentences. We talked already this one ribosome R N A. |
|
| 67:40 | there to make the ribosomes. All . So it's part of the |
|
| 67:43 | It helps to create this structure that's to read a strand of R N |
|
| 67:48 | called a messenger R N A. is the transcript of the gene that's |
|
| 67:53 | here in the DNA containing those exxons you need, that contain the instructions |
|
| 67:59 | make the protein. All right. , we're gonna process, we're gonna |
|
| 68:04 | this thing, we're gonna see how take a gene and we're gonna process |
|
| 68:07 | little bit in order to read, going to need R and A to |
|
| 68:13 | this messenger R N A. But bring in the amino acids to, |
|
| 68:18 | make your protein, you need a R N A which is called transfer |
|
| 68:21 | N A T R N A. we looked at the picture of the |
|
| 68:24 | N A and there was that little of a in the bottom corner. |
|
| 68:27 | was the R A that was transfer N A. And what it does |
|
| 68:30 | that there are different types of R A. They attach to a specific |
|
| 68:34 | acid and they serve as a carrier bring that amino acid to the |
|
| 68:39 | And when the ribosome reads a messenger N A, it puts the amino |
|
| 68:43 | in the right place. Now, we think of DNA, DNA and |
|
| 68:50 | nucleus are like, oh it's just , it's chromatin. Well, |
|
| 68:54 | it is chromatin, but chromatin is than just DNA. And again, |
|
| 68:59 | don't need to know the percentages, just to give you a sense is |
|
| 69:01 | DNA is not the biggest component of inside the nucleus inside chromatin. Chromatin |
|
| 69:08 | a whole bunch of proteins. These called his stones. That's what these |
|
| 69:11 | balls kind of look like. All . And what we're using is the |
|
| 69:17 | are a way to organize the And then there's also R N A |
|
| 69:21 | there as well. So chromatin exists multiple things. So if you're looking |
|
| 69:25 | a cell, ignore the chromosome for moment, then sorry, inside a |
|
| 69:29 | , that's kind of what a nucleus like, right? So you can |
|
| 69:33 | there's the chromatin and there's different types chromatin, there's croats, chromatin that's |
|
| 69:38 | being read and then there's chromatin that's doing anything that's been set aside. |
|
| 69:42 | not being used. The chromatin that's read is called euchromatin. All |
|
| 69:48 | So this would be what euchromatin looks . There's still his stones, but |
|
| 69:52 | at how the DNA is. It's of been unraveled, hasn't it? |
|
| 69:57 | ? It's like, oh, I'm to stretch it out so I can |
|
| 70:00 | what's on there. But if I'm reading the A, the DNA, |
|
| 70:04 | it's not being used by the it's more tightly wound up, |
|
| 70:09 | It's been set aside and pushed So it can't be red. That's |
|
| 70:14 | . And so when you look inside cell or inside that nucleus, you'll |
|
| 70:18 | areas that are dark in areas that light, the areas that are light |
|
| 70:21 | echt in areas that are dark or he achromat. All right. So |
|
| 70:25 | cell, what did I say? cell has all your DNA in |
|
| 70:29 | There are 33,000 genes, but not 33,000 genes are being used by that |
|
| 70:34 | . So some of it's gonna be , some of it's gonna be |
|
| 70:38 | all right. Now we refer to , his stones and the arrangement of |
|
| 70:42 | DNA on them as beads on a . And that's what you can kind |
|
| 70:45 | see here. And then, uh the period of replication, you |
|
| 70:50 | we don't want that because that seems , really unorganized. What we're gonna |
|
| 70:53 | is we're gonna compact it down so we can separate it out, |
|
| 70:57 | after we've replicated. And so what gonna do is you're gonna take that |
|
| 71:01 | and you're gonna form the chromosomes. so that's what a chromosome is. |
|
| 71:06 | just repackaging it, reorganizing it for purposes of replication. And then what |
|
| 71:13 | do is then you unwind it again you do it like that. |
|
| 71:18 | when I look at this and I when you look at this, it |
|
| 71:20 | unorganized, right? Does it look to you? Does that look |
|
| 71:28 | Two heads are nodding, the rest you are falling asleep? I think |
|
| 71:33 | looks unorganized. It looks like, know, think about like you ever |
|
| 71:37 | on a trip, right? You on a trip, got your |
|
| 71:40 | you're gonna fold everything, put everything nice and neat by the last day |
|
| 71:43 | the trip, what are you doing all your laundry? Just throw it |
|
| 71:47 | there. Maybe you get a bag it's like this is the dirty |
|
| 71:50 | but you still jam it in All right. That's what that kind |
|
| 71:54 | looks to me but the cell knows everything is because of all that, |
|
| 71:58 | laminin and all those structures inside No. Remember we're reading this, |
|
| 72:06 | is what we're interested in, in active cell. That's euchromatin. That's |
|
| 72:11 | the genes are. So you can that's what this picture is trying to |
|
| 72:16 | . And what we're gonna do is gene is just a sequence of that |
|
| 72:23 | , right? It is the whole along the length. And so most |
|
| 72:27 | they, they have uh varying the average is about 3000 nucleotides |
|
| 72:33 | right? It has a region that it, it has a region that |
|
| 72:37 | , we call the starting region, promoter, we have the ending region |
|
| 72:41 | the terminator. So what we're looking in this little cartoon is supposed to |
|
| 72:47 | the sequence that you're reading up And so you basically you read from |
|
| 72:51 | promoter and you go through the little things represent exxons, the little black |
|
| 72:55 | here with the triangle represents an intron you read along until you go to |
|
| 73:00 | to the terminating end. So this thing is supposed to represent a |
|
| 73:04 | but there's a lot of stuff in that's unnecessary for the R N |
|
| 73:08 | right? So the the only thing the, the R N A needs |
|
| 73:12 | have are these purple things because everything is just the extra stuff. And |
|
| 73:20 | the idea here is that even you're, when you make the R |
|
| 73:25 | A, it's gonna look like the whole thing. You need to |
|
| 73:28 | rid of all the extra stuff. you need to process it. So |
|
| 73:32 | transcript, right? So what did do is I transcribed? Remember what |
|
| 73:38 | , what we, how I describe DNA is like the blueprint at the |
|
| 73:43 | . You don't take the blueprint down the work site because you're gonna destroy |
|
| 73:47 | . So what do you do? make a copy when you copy |
|
| 73:50 | you're transcribing something, right? I need you to transcribe these notes for |
|
| 73:56 | . So make me a copy. that's what it's doing. That's the |
|
| 74:00 | is the copy, right? So take that transcript and you're like, |
|
| 74:05 | right, well, this has more than I need because it has extra |
|
| 74:09 | . So I need to process So this transcript is referred to as |
|
| 74:13 | pre M R N A. I processed it yet. And so then |
|
| 74:18 | gonna go through a process of Now, there is way more information |
|
| 74:23 | you need to know in this Back in the day. I thought |
|
| 74:26 | was important that you all need to this. You don't need to know |
|
| 74:29 | . All right. But you can up here, this is saying, |
|
| 74:31 | like I got Enrons, Exxon Exxon, Enron to. So what |
|
| 74:35 | gonna do is I'm going to first some modifications to the R N A |
|
| 74:39 | that it lives longer. All So that's what you see here in |
|
| 74:42 | cap and this poly tail, these things that just make the transcript |
|
| 74:48 | And then what we do is then go through and we excise the things |
|
| 74:51 | we don't need and we keep the that we do need. And so |
|
| 74:54 | what we're doing here. Notice you take different combinations and get different |
|
| 75:01 | So from the same transcript, you make different proteins. Hm Body is |
|
| 75:06 | of interesting figure stuff out like All right. But ultimately, what |
|
| 75:10 | do is you get down here and you have something that you can work |
|
| 75:15 | . All right, that those three at the bottom, these three things |
|
| 75:19 | the transcript that you're gonna use to the protein. All right. So |
|
| 75:26 | process of making protein is called I'm gonna translate the instructions from the |
|
| 75:36 | to make a protein. So really we've done is we've gone from nucleotide |
|
| 75:41 | nucleotide. So there's no translation, ? Nucleotide is a nucleotide is a |
|
| 75:46 | . Would you agree with me on ? What do you think? |
|
| 75:50 | If I say, write this out you copy me exactly. You're not |
|
| 75:56 | any changes. But the next step to translate into something different. You're |
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| 76:04 | nucleotides into amino acids. That's why translation is moving from one language to |
|
| 76:13 | one code to another Right. So first step, what do we |
|
| 76:17 | We transcribe, we went from DNA R N A, right? We |
|
| 76:21 | from the blueprint to the copy, made modifications to the copy so that |
|
| 76:25 | understandable. And then now what we're do is we're gonna take those instructions |
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| 76:29 | we're gonna read them and turn them that protein sequence, transcription, second |
|
| 76:37 | , translation R N A to Now, what do you need in |
|
| 76:42 | to translate? Couple of things you something to read. That's your M |
|
| 76:48 | N A, right? Messenger That's the thing that we modified, |
|
| 76:55 | ? That messenger R N A is tell us where we're going to |
|
| 76:58 | And what we're gonna do is when start, we're gonna read in three |
|
| 77:02 | sequences called codons, right? So , they're the code, right? |
|
| 77:08 | then, so there's one that starts molecule in your body has the same |
|
| 77:12 | codon, it encodes a methionine. every protein in your body starts with |
|
| 77:17 | methionine. Would you say methionine is important amino acid to have in your |
|
| 77:22 | at all times? Yeah. If don't have methionine, you can't make |
|
| 77:26 | , you can't make proteins. Your don't work. If cells don't |
|
| 77:28 | you die. Methionine equals life kind like football. Football is life with |
|
| 77:35 | life. Three of the codes tell when to stop. So when the |
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| 77:43 | frame, when the ribosome comes that code that code, that |
|
| 77:46 | you don't need to know them. just pointing them out. So |
|
| 77:49 | it says, OK, this is I stop, I've stopped making the |
|
| 77:52 | . OK? So all of them the same but three different ways to |
|
| 77:58 | . OK? So I need to a message. Second thing I |
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| 78:01 | I need amino acids. If I have amino acids, I can't make |
|
| 78:03 | proteins, right? So free amino , what they're gonna do is they |
|
| 78:08 | to be just freely available and then need to have the T R N |
|
| 78:11 | T R N A is gonna bind to the free amino acid. It |
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| 78:14 | along, grabs it. So here a free T R N A. |
|
| 78:18 | it is bound up. So that circle represents an amino acid. And |
|
| 78:23 | what we're gonna do is we're gonna the amino acids to the transcript as |
|
| 78:28 | is being read by the ribosome. the ribosome is the thing that actually |
|
| 78:33 | the reading, right? It's the that says, oh, this is |
|
| 78:37 | secret and this is the amino acid comes along and we're just gonna build |
|
| 78:41 | chain as it goes. All This is the last slide you have |
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| 78:48 | write something or you have to know . I don't want you to know |
|
| 78:51 | different codons, right? It's this is a uh a simple uh |
|
| 78:58 | a cross, not, not cross but basically it's a table that shows |
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| 79:02 | the 20 amino acids and the codes they're used to read them. You |
|
| 79:05 | need to know those. Ok. it's one of the ways that you |
|
| 79:08 | kind of look like and say, , I'm looking for reading frames. |
|
| 79:10 | can use this to kind of figure out and you can see that sometimes |
|
| 79:13 | are more than one code on for single amino acid. All right. |
|
| 79:19 | you can do that. The way you can think about this is that |
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| 79:22 | I'm looking at the DNA, remember said DNA gets translated into R N |
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| 79:27 | and then the or transcribed into R A R N A gets translated into |
|
| 79:30 | protein. So if you look at DNA, you can see the |
|
| 79:35 | that's what we call it in the . The D the triplet has the |
|
| 79:40 | of a codon. So those are codons, notice that they have cells |
|
| 79:44 | not uh uh thymine, right? the DNA would have thymine there. |
|
| 79:49 | you can look at the DNA and , oh, I cannot figure out |
|
| 79:51 | amino acid sequence is going to be because the protein has amino acid |
|
| 79:55 | So here is an example of a , right? The T R N |
|
| 80:00 | has a sequence that recognizes the code . And then that particular uh recognized |
|
| 80:06 | is belongs to the T R A car carries methionine in this particular |
|
| 80:10 | So that's how you kind of get trans translation going along right now. |
|
| 80:18 | just wanna show you this. I want you to know this, this |
|
| 80:21 | kind of showing you how it All right, there are three different |
|
| 80:27 | , there's the part where you are in. So you can see which |
|
| 80:31 | am I reading? I'm reading in direction from the five prime end to |
|
| 80:34 | three prime end. All right. the first thing that I'm reading is |
|
| 80:39 | right there, I bring in the R N A, the T R |
|
| 80:42 | A that can recognize that sequence comes bringing its amino acid, the extending |
|
| 80:49 | is gonna be found in the middle . So you can see this is |
|
| 80:52 | protein that's being extended. What happens , is as this goes, this |
|
| 80:55 | moved over to there that shifts Now this one's empty. So it |
|
| 80:59 | over to this spot and then as moves on, it pops out and |
|
| 81:02 | it goes find its own amino And so it just constantly moves in |
|
| 81:05 | direction and your protein is extending, the long chain to the new one |
|
| 81:11 | come along. So that's how you it right. So if you are |
|
| 81:16 | the codon, the next codon in sequence of the cystine, so what |
|
| 81:20 | be looking at is this is the uh peptide. This is the next |
|
| 81:26 | , the next one, the next , the next one, then the |
|
| 81:28 | one and then you can just kind go down and see each triplet as |
|
| 81:31 | going along. And I'm gonna guess these match up. Um Yep. |
|
| 81:37 | . So they're matching along. And this would be the terminal region and |
|
| 81:43 | is coming over here to the sea region in this particular model. And |
|
| 81:49 | that's how you make proteins. You read M R N A with a |
|
| 81:54 | with the right T R N A in the right amino acids until you |
|
| 81:57 | across a stop code on. In case you stop and you release the |
|
| 82:05 | , rough endoplasm curriculum. That's all doing. I'm just extending this thing |
|
| 82:10 | , but I'm extending it into the . The thing that's interesting about this |
|
| 82:15 | and why I wanted to show it you. And with this one up |
|
| 82:18 | is that it's not one ribosome at time. What we're doing is we're |
|
| 82:24 | a single transcript and we're using multiple to read it. And so for |
|
| 82:31 | transcript, you can get multiple right. So this is showing you |
|
| 82:37 | completed protein, this is almost this is even less completed, this |
|
| 82:40 | even less, less completed, this barely started. But in the |
|
| 82:44 | what you're going to end up with tons and tons of protein. So |
|
| 82:47 | you need is a transcript, a transcript to do So, and we're |
|
| 82:56 | down to the end, which is of nice because I know your brain |
|
| 83:01 | turning into, he's gonna put Chocolate proteins have shapes. All |
|
| 83:15 | all proteins have shape. We even it. We said if we apply |
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| 83:19 | or P H that shape goes out whack the protein can't do what it |
|
| 83:22 | to do. So that means its is important. How do we get |
|
| 83:25 | to the shape that it needs to ? And this is the weirdest thing |
|
| 83:29 | biology. I still don't understand I think it's the coolest, but |
|
| 83:32 | don't understand it. All right, are proteins called chaperones. All |
|
| 83:39 | And this is as close of, , of this is what they look |
|
| 83:43 | , they look like, uh, shakers, you know, like cocktail |
|
| 83:47 | . All right. So this is stage of biology where magic happens, |
|
| 83:52 | ? So, as a protein is made, what happens is, is |
|
| 83:56 | chaperones come in. So these are of other uh chaperons that have come |
|
| 84:01 | and they help twist in the bend . And what they do is they |
|
| 84:04 | into these larger chaperones and then literally cap comes along. So there's your |
|
| 84:11 | , it comes along and then, it comes out the right shape. |
|
| 84:20 | don't know how it does, but pretty cool. All right. |
|
| 84:25 | the reason we have to do this if you get a accidental folding, |
|
| 84:28 | it doesn't fold correctly. What happens you'll create inappropriate a activation sites, |
|
| 84:35 | that will cause activity that the cell want, which is bad. |
|
| 84:40 | So this ensures that you get the shape of the molecule. So that |
|
| 84:45 | the right thing. This is an field. Every protein in your body |
|
| 84:50 | folded and I don't know how it how to do it, but it |
|
| 84:56 | kind of cool. Huh? All . So just know that protein proteins |
|
| 85:01 | folded because they have an assistant or chaperone that helps it along its |
|
| 85:11 | So what we've done is we've moved DNA, right? DNA is your |
|
| 85:17 | which have all these weird sequences that to be processed or copied and then |
|
| 85:23 | process, then that R N A red and you get these proteins that |
|
| 85:27 | folded and it's the protein that does the work in the cell. It's |
|
| 85:31 | thing that makes your cells do the that it does, right? It's |
|
| 85:35 | interesting. So, proteins have inherent them four levels of organization, |
|
| 85:45 | We said proteins are made of amino and it's the sequence of the amino |
|
| 85:50 | that make them interesting, right? like words are sequences of letters, |
|
| 85:57 | are sequence of amino acids. So primary structure of a protein is the |
|
| 86:02 | sequence in order of those amino acids the internal to the C terminal. |
|
| 86:07 | right. So that's the lowest order right, that's the most simple structure |
|
| 86:13 | a protein. But because of those um I don't know where is |
|
| 86:18 | our group, each of these proteins these unique interactions with their surrounding |
|
| 86:25 | OK. And so what will happen , is because of those interactions, |
|
| 86:31 | get some really interesting shapes. Two particular have are, are repeated structures |
|
| 86:37 | appear over and over and over All right. So what you end |
|
| 86:42 | with is these things that are called structures. So the sequence gives rise |
|
| 86:46 | secondary structures. This is an example a beta sheet. And what's happening |
|
| 86:51 | is that the sequence causes the the chain to kind of move back and |
|
| 86:55 | . So it creates kind of this area and that's what these arrows are |
|
| 87:00 | here. It's kind of this flat for the protein. It creates kind |
|
| 87:03 | unique interactions with the surrounding environment. thing is that the sequence can cause |
|
| 87:08 | force a helix and this is an helix. And so that's what all |
|
| 87:12 | little curly looking things do. And now what we have is we have |
|
| 87:17 | secondary structure that begins to bend and the molecule into a specific shape. |
|
| 87:23 | notice in secondary structure, we're dealing a small region, right? This |
|
| 87:28 | a small region, that's a small , that's a small region. So |
|
| 87:33 | structure gives rise to shape to the and then it's the sum of these |
|
| 87:39 | structures that give rise to the shape the entire molecule, which is what |
|
| 87:44 | refer to as the tertiary structure. it's this thing that we really care |
|
| 87:49 | . Actually this is the example of secondary structure right here. So there |
|
| 87:52 | can see the beta sheet there, can see the helix, all |
|
| 87:56 | So this provides flexibility that provides that's not so important. Just no |
|
| 88:02 | structure gives rise to tertiary structure. right, the tertiary structure is the |
|
| 88:10 | of the entire molecule. Now, proteins have are there's two types of |
|
| 88:14 | in your body by shape globular What do you think globular proteins look |
|
| 88:18 | globs? Yeah. And then you stringy like proteins. There's a different |
|
| 88:23 | for it. I can't think of they're called but like your collagen. |
|
| 88:25 | right, you guys are young, collagen is still tight, you're not |
|
| 88:28 | anywhere, right? I'm I'm That's the real sag, right? |
|
| 88:39 | is more rope like. And so this tertiary structure which arises from secondary |
|
| 88:47 | that gives the protein shape and its to interact with its environment and the |
|
| 88:53 | that it does. Now, this is a function of, of all |
|
| 88:57 | types of bonds and interactions between all side chains. And so again, |
|
| 89:01 | don't need to know the names of these different types of bonds, but |
|
| 89:03 | are different types of bonds that allow interaction So they're trying to show you |
|
| 89:07 | , you know, hydrophobic interactions. does that mean? Well, that |
|
| 89:10 | I don't want to be around So I bend myself inward. And |
|
| 89:14 | these hydrophobic side chains are now internal the self poking other ends out, |
|
| 89:20 | ? And now I have an environment can now interact or a region that |
|
| 89:24 | now interact with the external environment, ? So outer stuff faces outward to |
|
| 89:34 | with the environment. Other things that been pushed inward are there to hold |
|
| 89:38 | together and maintain the shape that's tertiary . It's the shape of the whole |
|
| 89:45 | . It is what determines its interaction its environment. Some proteins have what |
|
| 89:51 | called a quinary structure. This is molecule you've seen every time you talk |
|
| 89:55 | proteins, this is hemoglobin. Why we talk about it? Why do |
|
| 90:01 | use it? Because it demonstrates all things that we want to talk about |
|
| 90:05 | structure here is dealing with four or or sorry, four more two or |
|
| 90:09 | because this is four polypeptide chain, chains mean basically a protein. All |
|
| 90:16 | . So here's hemoglobin, you have , they should be opposite. I |
|
| 90:21 | know why they did it this Two betas, two alphas inside you |
|
| 90:26 | a non pertinent structure. Those are um um I mean, they're, |
|
| 90:34 | the word I'm looking for here is prosthetic groups. All right. So |
|
| 90:40 | essence, it's not just protein, can see there's other things in |
|
| 90:43 | And so these things are being held , not by protein, protein |
|
| 90:48 | but by attractions, which is what these things are saying, right? |
|
| 90:53 | basically held together. If I wanted um uh break this thing apart, |
|
| 90:58 | just use a little bit of soap it would all fall apart because it |
|
| 91:01 | those interactions, right? So some are gonna be uh or proteins will |
|
| 91:09 | an aggregate of many different little proteins together. And this allows you to |
|
| 91:15 | much more interesting things like a series chemical reactions very, very quickly but |
|
| 91:21 | all proteins will have this. So structure is like this special category where |
|
| 91:27 | the sum of many different peptides working . So structure is really important. |
|
| 91:38 | is really important because it allows for to interact and do things and what |
|
| 91:45 | wanna do just to kind of sum up here. I think we only |
|
| 91:49 | like how many more slidess? Six I do? Like one a |
|
| 91:55 | Will that make you happy? You're hell, no, he's talked too |
|
| 91:58 | already. All right, we're gonna kind of wrap everything up in a |
|
| 92:02 | bow and just kind of walk out here. All right. Did you |
|
| 92:05 | how when at the beginning of the I kind of walked through very specifically |
|
| 92:08 | went to nucleus to rough in the , in particular there was an order |
|
| 92:11 | I was kind of going one to next to the next to next. |
|
| 92:15 | , those things together are referred to the in the membrane system. And |
|
| 92:19 | I'm just gonna walk through the inner system with you. All right, |
|
| 92:22 | have the nucleus right, holding the information making R N A R N |
|
| 92:28 | gets turned into proteins. So proteins be made out in the cytosol, |
|
| 92:32 | it can also be made in the endoplasm reticulum. So the rough endoplasm |
|
| 92:36 | remember is an extension of the nuclear . And then from the rough endoplasm |
|
| 92:41 | , I get vesicles and those vesicles being shipped over to the golgi, |
|
| 92:46 | ? And the Golgi does sorting and and then from there vessels are popped |
|
| 92:52 | again from the trans side and then they're going to do is either I'm |
|
| 92:55 | to secrete or I'm going to merge the plasma membrane, right. So |
|
| 93:00 | those things together, these structures collectively referred to as the endo membrane |
|
| 93:06 | All right, they're interconnected with one , either directly like what we saw |
|
| 93:11 | or indirectly through those vesicles to allow the movement of proteins to the surface |
|
| 93:16 | for secretion. So there are parts work together to accomplish a single |
|
| 93:23 | All right. So protein sensor is we start transporting to where we |
|
| 93:27 | We're also gonna see some metabolism as and some detoxification because lysosomes play a |
|
| 93:33 | in that system as well. But all share membrane. So if I |
|
| 93:38 | to make new membrane, where does all start over here, the nucleus |
|
| 93:44 | it just kind of works its way up to the plasma membrane, I |
|
| 93:48 | recycle off that as well. Vesicles said exist. But we don't, |
|
| 93:55 | not just free floating, they're not sorting themselves and kind of going wherever |
|
| 93:59 | want to go. They're actually We have these things called motor |
|
| 94:05 | So here we see a microtubule, a vesicle or an organelle and then |
|
| 94:13 | is a motor protein. Now, video I showed you has a picture |
|
| 94:16 | one of these things and if you watch this thing, it's based off |
|
| 94:19 | electron micrograph of these things moving. I'm telling you this thing couldn't have |
|
| 94:24 | created by anything other than Disney because looks like a cartoon character. You |
|
| 94:28 | what it has, it has these feet that are a T P |
|
| 94:32 | So A T P comes along. , you get catalyzed of that. |
|
| 94:36 | T P releases the energy and it the foot to lift up and move |
|
| 94:41 | and it walks like this. And you can imagine here it is carrying |
|
| 94:47 | big old mitochondria. It's the goofiest thing you'll ever see. There's different |
|
| 94:54 | , there's dines and, and you tell by their name that they play |
|
| 94:57 | role in motor and movement. But point in all this is that nothing |
|
| 95:02 | free floating in the side is it's all being directed. It all |
|
| 95:06 | pathways and structure around it that allows that particular type of movement. And |
|
| 95:12 | when it gets to the membrane, not just like la, la |
|
| 95:15 | I'll just float to wherever I There are docks and docking material on |
|
| 95:20 | vesicle to direct it to where it's to go. All right, these |
|
| 95:24 | called the snares, right? Snares , these is, is complex of |
|
| 95:29 | . Very, very complicated, but can think about it like this. |
|
| 95:32 | , there's snares on the vesicle and , there's snares on the membrane. |
|
| 95:37 | the snares on the vesicle are called snares for vesicles t for transport, |
|
| 95:43 | think. All right. And basically it does it says or target. |
|
| 95:46 | you go. It's even easier. it's real simple. Basically, the |
|
| 95:50 | shows up to where it needs to , but I'm not gonna release everything |
|
| 95:53 | away. I'm gonna wait until you me to release stuff. And so |
|
| 95:56 | lines itself up and get ready to , release some materials and then when |
|
| 96:01 | signal comes along off, it opens all the material comes out and then |
|
| 96:06 | vesicle fuses with the membrane and becomes of the plasma membrane. That's how |
|
| 96:12 | snares work. And so this is that your cells use all the |
|
| 96:17 | It's not just this. Oh, can go wherever it wants to go |
|
| 96:20 | often. Calcium is the signal. , the next slide, please don't |
|
| 96:25 | through and memorize this just but do memorize. But if you want to |
|
| 96:29 | the steps and all the things that involved, you can just kind of |
|
| 96:32 | through this and look at it. if you're not interested, that's ok |
|
| 96:35 | . Right. I make my, , my upper level students learn that |
|
| 96:41 | it shows you like, look, , I'm, I'm ready. All |
|
| 96:44 | gotta do is to tell me to oh add in the calcium off. |
|
| 96:46 | go it's kind of cool. And in the end membrane system here we |
|
| 96:56 | pinching off from the goal. What we do with that? Right. |
|
| 97:00 | one of the things that we can is we can become a lysosome or |
|
| 97:03 | become a transport vesicle so that we either secrete the material or here's an |
|
| 97:09 | of a receptor being joined in. so up it goes, it, |
|
| 97:13 | forms with that snare sits in the and when it's told to it, |
|
| 97:17 | goes like this. So you can it fuses and opens up. So |
|
| 97:23 | opens up so that the inside is facing outward, look at the direction |
|
| 97:27 | which the receptor is pointing, it's into the vesicle. So when that |
|
| 97:34 | opens up, the receptor is pointing way outward. So now it can |
|
| 97:42 | signals from the outside. So these the three things that you can |
|
| 97:47 | If you can go through the new system, hydrologic enzymes become lysosomes. |
|
| 97:55 | I just throw this up here just remind you what a lysosome is. |
|
| 97:58 | don't even need. That's the same . And here we are at the |
|
| 98:04 | slide we're getting done 20 minutes till can go get your coffee. |
|
| 98:14 | Or maybe I should talk for 10 about proxy. No. OK. |
|
| 98:18 | right. Or I say proxen, not everything in your cell needs to |
|
| 98:24 | around forever. In fact, most the things you want to destroy almost |
|
| 98:26 | quickly as you make them. Just general rule. It's like we don't |
|
| 98:31 | to keep stuff around. This is garbage disposal of the cell. All |
|
| 98:37 | . And what happens is as as a protein becomes uh damaged or |
|
| 98:42 | longer needed or, you know, , or it's been poorly folded because |
|
| 98:47 | whole, you know, a cocktail didn't work. We want to get |
|
| 98:50 | of that stuff because it can be to the cell and the process of |
|
| 98:54 | cell. And so this structure which in the side is all this proteome |
|
| 98:59 | is there to serve that purpose of this. And so the first thing |
|
| 99:02 | happens is the protein gets tagged to destroyed, right? And so there's |
|
| 99:06 | proteins called ubiquitin. That's what the B stands for and it's called ubiquitin |
|
| 99:12 | the proteins are found everywhere. it's ubiquitous protein. See, stupid |
|
| 99:18 | . And then that tag is a to say, oh um I can |
|
| 99:23 | you now. So I will feed into the proteome and then out of |
|
| 99:26 | bottom after grind it all down. when you end up with a bunch |
|
| 99:30 | amino acids and then once you have acids, what can you do with |
|
| 99:33 | acids recycle and make more protein? this is just a simple way of |
|
| 99:40 | proteins and protein degradation for the purpose the cell, right? We're done |
|
| 99:52 | the day. Um Like I for those of you came a little |
|
| 99:55 | late. I know most of you here right on time. But you |
|
| 99:58 | , when I started talking, um have a 7 30 meeting tonight with |
|
| 100:02 | CASA people. I'm really happy that at 7 30 at night because |
|
| 100:07 | you know, um but hopefully, after that meeting, we'll have uh |
|
| 100:12 | test available and a thing to sign for, I'll email you as soon |
|
| 100:16 | I know that the sign ups are and available. So it'll either be |
|
| 100:21 | , you know, after my meeting it will be tomorrow morning if it's |
|
| 100:25 | completed after that meeting. Ok. everyone's on the same page. No |
|
| 100:30 | has, you know, quick access anything like that. You guys have |
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| 100:35 | great day. I will see you about this. We are three days |
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| 100:39 | , we are almost a quarter of semester done. All right, you |
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| 100:45 | have a great day. I'll be my office for at least an hour |
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| 100:49 | if you need |
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