So we're delving into chapter 3 now. So this is specifically on cells. As you can see the chapter objectives here, 1, 2, and 3, we're going to talk about the structures.
So what is inside a cell? All the organelles. Remember organ and then L. L means little. Little organ inside of a cell.
We're going to talk about how do cells get the molecules they need to keep us alive. How do they get the molecules they need, like glucose and oxygen, in order to metabolize that into ATP? I'm starting to, as you'll find when I go through the chapters, I'm going to introduce future vocabulary and keep repeating it and repeating it to try to role model. That's how you get this into your head.
I've mentioned before, there's no way, there's no magical pill, there's no magical method. It just takes repetition. I've shared my story with you about learning chemistry and it was pulling teeth, but don't give up. It really will click.
It'll feel like you're going uphill, going uphill, ready to be exhausted, and then it'll all come clear. But you've got to keep at it, okay? The third objective is cellular homeostasis. We're going to put some of this together and talk about more of the homeostasis processes, such as we've already mentioned from Chapter 1, which was protein synthesis.
Enzymes perform metabolism inside of cells. So I'm going to keep repeating these vocabulary words within a sentence, and until you can use it as a sentence, that's like a concept map inside of your brain as you speak. Isn't that crazy?
So enzymes are protein molecules that do metabolism. They do catabolic and anabolic reactions in order to keep you healthy, and they do this inside of your cells mainly, working with what we're going to cover in this chapter, which are organelles. Okay, replay this if you have to. Some of you might be getting overwhelmed by the vocabulary by now. Again, I'm going to cover that in this chapter too, but you have to know the chapter outline, and we're going to talk about that.
Here are some quotes from the first paragraph of the chapter, which you should have looked at by now. Again, if you haven't learned the chapter outline and you haven't looked over the chapter, this isn't the time to watch the video. Now, that being said, if you're a person that learns by repetition and you're going to watch these videos a couple of times, that's fine. I'm not telling you how to learn.
I'm just saying if you think you're going to play this video and it's just going to magically make sense in your brain, that's normally not the case. Some people can learn like that. I totally was not one of those people.
So just as we're getting started in the term, I want to make sure that you're doing your level best not to get frustrated. So that's why I like teaching these introductory classes, because this is where we make or break ourselves. We can tell ourselves, oh, this is too hard, I can't do math, or I can't do science.
Usually it's your approach. And I'm sure everybody's had that take in their life on something that, you know, it was just your perspective. If you just would have tweaked your perspective. I just had this happen to me the other day teaching a class.
If I just would have looked at the situation differently, it would have been more enjoyable. It's madness, I know, but we all do it. And normally when I find myself doing it, the worst is when I'm blaming someone else instead of taking ownership of what I can do.
So think about these things. It's just part of being human. It's not a judgment call. But what I have found... is if someone can help me get out of my own way, that is the most powerful tool they can give me.
And we all need reminders of that. So I'm off my soapbox. Okay, so some crazy facts here, right?
So live in a lifetime, 10,000 gallons, so on and so forth. You probably already read them. Think about that, though.
Think about the volumes of what is being listed here, and that your cells, microscopic, you can't see them with an unaided eye, make this. much stuff and we go around and we can't find our car keys or something. It's almost crazy, but all of these total up to the cell's metabolism.
In other words, metabolism. What are they doing to keep us in homeostasis, to keep us alive using enzymes and organelles to do it? Review on cells.
Again, you're going to see I use more and more GIFs because I think they help because you can kind of watch them as you're listening. The upper right hand corner is a pulsing arteriole and the reason I know it's not an artery, it's not big enough, the reason it's not a capillary actually There is a capillary here off to the side where one red blood cell comes through. But this is an arteriole that's a little bigger because it has a lot of blood cells in it, relatively speaking, to this capillary. Capillaries are the smallest vessels in the body. Down here is a capillary, and you can see the insulin landing on the cell receptor.
We brushed on that roughly during lipids in Chapter 2. And then the insulin is going to land on the cell receptor. And that will allow the glucose then, the transporter opens and the glucose comes in. Ultimately, the mitochondria is an organelle we're going to talk about in this chapter.
We'll take the glucose and the oxygen that's just diffusing into the cell and turn it into ATP. Now that in detail is covered in Chapter 4. That's called cellular respiration. We're only going to talk about the organelles and their basic functions in this chapter.
and then on transport and how these get in and out. Some of you might have read ahead, and you might have read that oxygen will diffuse, which means just going from a higher concentration to a lower, kind of like someone spraying perfume in a room and you can smell it on the other side. The other transport in this GIF is insulin.
Notice how insulin facilitates glucose into the cell. Glucose cannot just move in freely. It has to have the quote-unquote protein transporters on the cell membrane open for it because it's too big to get in on its own. So insulin facilitates the glucose in.
And if you think about that, it makes sense because facilitate, the definition of facilitate means to help. So we're going to work on a couple of these things. I'm going to post them up here.
So we got the definition. You probably got that as you worked through the chapter. The cell is the smallest functional unit of an organism.
Not the smallest matter, like the smallest functional unit. There's a difference, so make note of that. Microscopic cell size is due to what? That was from chapter 1 and 2. Mainly chapter 1. Volume to surface area ratio. The volume cannot get big in relation to the surface area or what we're going to talk about today.
Molecules can't get in and out and that's bad for the cell. Curious about what is a chicken egg? A chicken egg, depending on if it's fertilized.
If it's not fertilized, it's just a gamete, believe it or not. And it's very microscopic. Most of the egg is just a picnic basket for the peep. That sounds funny, but eggs are perfect food.
You might have heard, oh, they're bad for you. Okay, well, they're not. If you ate 12 a day, maybe.
But eggs are the perfect food because think about it, there's no umbilical cord to a chicken egg. If a chicken egg is fertilized, then there's a zygote in there, so sperm at the egg, and then that zygote will grow and grow, and what does it have to use for materials? The egg white and the yolk, right?
So it has a perfect balance of digested cholesterol and digested protein. An egg is a perfect food. I had a student ask me a question once. about how eggs are fertilized. And I had to share a funny story about my neighbor who thought that roosters have a penis.
I can say that in this class because, you know, it's biology. Roosters do not have a penis because they're like frogs. So they spawn, so to speak.
So a rooster actually will spray the sperm on the back of the hen's feathers, and then as the egg comes out and is laid, then the sperm will swim in through the pores in the egg and fertilize it. I cannot believe how many people don't know that. We all need to get in touch with our food a little bit, right? What is bigger, molecule or cell? You should know that by now.
Cells are ginormous. Consider the room you're sitting in right now as a cell, and the eraser on a pencil or the tip of a pencil is a molecule. That's probably...
It's probably even smaller than that, but I'm just trying to give you an analogy. How do we see cells? Most of you have probably used one, which is a microscope. And now this one. What can be denatured and how?
So you're supposed to go back in your memory from what you did in Chapter 2 and think about this. Denature. Take away the natural shape.
Remember the alcohol dehydrogenase story? With alcohol dehydrogenase, what helped it? NAD. And what did alcohol dehydrogenase do? Took away the H's from the ethanol.
That's how the liver makes that enzyme to detoxify alcohol if we consume it. Otherwise the alcohol would kill us. And there are ethnic groups of people that either have lower levels of alcohol dehydrogenase and can get totally trashed on one beer, or they don't have any and it's toxic to them.
That's a truism. So you might have, you don't have to admit anything, been in a party or heard a story where someone was drinking alcohol and was having a good time, and then five minutes later they're passed out on the floor. You might think, how can that be? that happen?
It's now you might know, right? Did you apply that knowledge? Think about that.
How did they go from being the life of the party to passed out on the floor? They drank so much alcohol. That's how fast it happens. When NAD can't carry the H away, the H is built up, denature the alcohol, dehydrogenase, and the person's just passed out because they can't deal with the alcohol.
It's almost as if the body Collectively, the cells are saying, you've got to knock this person out because if they keep drinking they'll kill us because now they have no alcohol dehydrogenase. Think about it. If it all denatured, they're unprotected from the toxin.
And someone who drank that much, and usually it's liquor, will be drunk until the next afternoon. Technically, blowing into a blood alcohol content measure, they would be drunk until the next afternoon. because they have no more alcohol dehydrogenase and the alcohol is just sitting there and it has to wait until the liver can make more.
Isn't that crazy? We do the darndest things to ourselves. How about this? Denature and catabolize. I want you to work on these words so that you don't confuse them.
And usually I bring these up because I see that's what students get wrong on the exam. So don't blow this off. You might not think you're going to get confused, but I'm doing this for a reason.
D-nature is to an enzyme where it's completely misshapen and unusable. To catabolize means to break a large molecule into smaller molecules, completely broken apart, so that they can be used. So those are two clear separations of those terms. And then cells have to be in what where we have a disease, homeostasis.
And I point this out because there's so much in nutrition going on right now. I made a point of this in the beginning of the chapter. Angus Barberieri, he was a very, very overweight Scotsman. If you click on that link, it takes you to a YouTube that shows that it's not the 3-3-3 rule.
What is it? Three minutes without oxygen, three days without water, three weeks without food is all we can survive. This man lived a lot longer without food and got down to his healthy weight. And I mean he took in no calories for that amount of time.
So read about that in the book. It's really interesting. And watch that video. It's crazy. And he did it under medical supervision.
So it wasn't like he went to his house and just went nuts. It was under medical supervision. And here's another image showing you what you can do with just a simple change of diet and a little exercise.
This is mitochondria inside of a person who's in metabolic syndrome with diabetes, and this is muscle tissue around it. This is after two weeks of minor walking and watching fiber content, increasing it and decreasing caloric intake. Actually, just eating more fiber will do that naturally, but look at the difference. Look at the lack of fat, and here's another image of it.
So this is... Shown, it's on the American Diabetes Association. This was only after two weeks of intervention. And when I say intervention, it was minor. It was just a simple uptake of fiber and walking on a daily basis.
And you can see all the fat content here, this white stuff, is now gone. So it's that quick to turn things around in your health. So homeostasis equals what? Equals what?
Homeostasis equals metabolism, which equals life. And if you want to add in there now, it's performed by enzymes and organelles. So here's what we're going to do.
Here's a cell. This is the picture. I don't really like it, but it's the one that's free on Wikimedia. And I would never put this on an exam. And it's in your textbook.
So we're going to work through it. Instead of just willy-nilly going through the organelles, which you can do in your book, it's all numbered. I'm going to work through a food label.
I'm going to show you how Chapter 2 applies to Chapter 3. So, we're going to start with proteins. And this I got a gift to kind of help you. As you see the nucleus in the center of this bizarrely drawn cell and the DNA is in yellow and the DNA is going to open up one gene and it's going to have that gene read by RNA. That's as far as we'll get by now.
And then the RNA is going to go out to the ribosome. The ribosome is that green thing. Now I'm looking in the small purple diagram that's moving in the bottom right of the screen.
On the big picture, the ribosomes would be number three, the little tiny dots all over that blue maze. So the ribosome in the bottom right down here is the green thing. And what it's doing is traveling along this RNA, which is actually an exon, we'll get there, this RNA, messenger RNA, and reading it. And that's going to make a polypeptide.
Remember back to Chapter 2 in that chart? That's going to make a polypeptide. And then the polypeptide will then go into this blue maze. So it's going to go from the nucleus to the ribosome, out to this maze, which is the RER, and then onto the RER, which I kind of did a box right here in the bottom right, because it didn't have it on the diagram, is going to fold the protein into the correct shape. So let's work this through with alcohol dehydrogenase.
Say you're a typical person that has it. So you're going to have a gene. on your DNA in the nucleus here.
So that's right here. You're going to open up the alcohol dehydrogenase gene. That gene is going to be coded into RNA in the nucleus.
Then that RNA is going to leave the nucleus and go out here and the ribosome, number three up here, is going to read that RNA, which is the decoded alcohol dehydrogenase gene. That is going to be made into a, the ribosome is going to make that gene code. into a polypeptide of alcohol dehydrogenase. And then ultimately, that polypeptide is going to go into this number five huge blue maze, which down here in the GIF is known as RER.
And that is going to fold it into functional alcohol dehydrogenase. So typically, when it's done, the ribosome is done, it is not functional. It is just a polypeptide.
It's done in the RER. It's a functional protein. So that is how the DNA that your parents gave you becomes you.
Remember from Chapter 1, DNA becoming you. Protein synthesis. Genes, your genotype, becoming your phenotype, which is the protein.
Start to the P. So again, I'm trying to lead you into other course content. So that's an actual protein. So now we're going to go and talk about how a lipid is made. A lipid, so remember, we're doing a food label.
So we just did protein. Let me say, the only other thing I want to add to a protein is once the protein is folded into its right shape by the RER, rough endoplasmic reticulum, it's going to go out here to number six. That's the Golgi.
Golgi, Golgi, it doesn't matter. That is going to do some more. moderation to the protein, I'm not going to ask you that.
I'm just going to ask you to remember that Golgi packages and ships, and we either transport it outside of the cell through the phospholipid bilayer, which is another organelle, or it will transport it in the cell. So from the Golgi, the protein will either be exocytosed through the phospholipid bilayer. So you've got to say these a few times. or it will be endocytosed into the cell for an intracellular enzyme or whatever the protein is that's being made.
I just used an enzyme as that example. It could be muscle, it could be skin, it could be immunoglobulins for your immune system, it could be anything for protein. Okay now we're going to do smooth, we're going to do the carbohydrates and lipids from a food label.
So we start in the nucleus and instead of going to three and five which is ribosomes and RER we're going to go from the nucleus you don't have to know the difference between one and two just the nucleus out to number eight which is the smooth endoplasmic reticulum now the way I remembered this was fat is slippery right it's greasy it's slippery so smooth slippery if that works for you if not make another association technique but you want to have something not to confuse ser and RER Then the smooth endoplasmic reticulum is responsible for putting together carbohydrates and lipids. And then again it would be either sent into the cell, not typically through the Golgi. into the cell or out of the cell through the fossil lipid bilayer to do work in another cell or another area of the body.
Or in another cell. It could vary. It wouldn't ask you that question.
So let's discuss. So that's carbohydrates, lipids, and proteins. If you need more on this, just go back on this video and replay it. And follow along in the book and highlight how I said it here and how it's said in the book.
Over here, 13. are centrioles and again I wouldn't have the image you just have to know the function. Centrioles for this point in time all you have to know is they have to do with chapter six which is cellular production and those two processes are mitosis and meiosis, cell division, making more cells. Mitosis meiosis is the same as cellular reproduction is the same as cell division.
On the mitochondria you might have identified right away number nine here that's responsible for taking in glucose and oxygen as reactants and turning them into carbon dioxide and water and through that equation they're going to make atp which is called cellular respiration which is chapter four okay so if you have to play this over play it over uh 12 10 are pretty much the same we're going to call them and four for the sake of this class Vacuoles or lysosomes. So lysosomes are different. I'm not going to use an image. Let's just say number four is a lysosome. Think of the prefix lys.
Lys means to split. So what the lysosome does, I talk about it in the book with autophagy. Autophagy is huge right now.
It was a Nobel Prize in 2016. When you go with calorie restriction, your cells will actually clean up their mistakes and fix problems. People have reversed, millions of people have reversed type 2 diabetes during this by either restricting food for 16 hours a day, only eating in a certain window, like 8 hours or so, or going for a day or two without food regularly. And there are people that swear to this and now we have molecular evidence that it works.
Dr. Jason Fung, I have a couple links to him. He's a real nephrologist at the University of Toronto. He's a doctor, he's a medical doctor. And he has his patients do this now with a phenomenal success rate.
I implore you to look that up, especially with the way the health of our nation is going. There's a documentary on YouTube right now for this. HBO does it.
It's pretty well done. They have a lot of good information and interview a lot of quality people. And it's free on YouTube.
The Weight of the Nation, I think, is the name of it. But autophagy is performed by lysosomes. have even termed them autophysomes.
They give them a certain name. But lysosomes do this. In other words, when you withhold nutrients and energy, your cells have to find it elsewhere.
So you're forcing them to clean up mistakes. And that's what that organelle does. It's very, very powerful. This research has just come out in the last 10 years really strongly, like a lot of backed up molecular research on this.
And 10 and 12, let's just call them a vacuole. They will store good things and bad things for destruction or for use later. So I got some more gifts.
This is just a review. This is a ribosome. Amoeba Sisters did this. I thought it was pretty helpful. You can see the RNA going through it.
They gave a very specific mRNA, which we'll get to in, I believe, maybe the end of this chapter. mRNA is called M for messenger. It takes the message from the DNA to the RNA.
to the rRNA, sorry, the ribosome is the rRNA, even though we're calling it the ribosome for now, and the mRNA comes out, and then that is read by the ribosome, and then you can see the amino acid chain come out. That's the polypeptide, remember? Amino acids are the subunits of proteins, and they will be just put together in a chain, a polypeptide at this point.
What folds it into the right shape? The RER. So here is the polypeptide that this gift is turning out. I even like the fact that the color matches. And then the RER will fold it into an enzyme, which is the right shape, or another protein.
I have that clickable on most of these slides. Here's another image from your book. This is showing you that some are polar, some are nonpolar. Remember that from Chapter 2? That's why they start torquing back on themselves, kind of like a magnet repelling.
two of the same ends or attracting two different ends and then ultimately it will become properly folded hopefully and then work to do metabolism And so just making sure we covered these. Yes, proteins that do metabolism, correct. And those are enzymes. And here is a GIF of what that looks like when it denatures. And you saw this in Chapter 2, the Chapter 2 video lesson as well.
So there's a functional protein, then pH or temperature starts changing, and it becomes... is unfunctional. And if you notice, this really resembles the diagram above it if you reverse the arrow. It goes from the proper shape on the right back to the polypeptide on the left. Some students have asked me, well, will it go back to the proper shape?
Normally it doesn't from the literature that I read. Normally it'll just be recycled by the lysosomes and the amino acids will be reused in other protein structure assembly. Of course I have to do this. That is actually what molecular biologists have found to be the motor protein.
So this is a motor protein delivering a molecule inside of a cell walking along the cytoskeleton. That is not made up. That is based on what they have used with electron microscopy to be the actual shape and the actual functionality. of these dynein proteins.
Dyn just means a unit of energy. So you've seen this before. This came up in chapter two.
This is the phospholipid bilayer. So this is a review. You can see the glyco, the carbohydrate protein as the cell receptor.
You can see the protein channel that allows the membrane to be selectively permeable. And you can see cholesterol in here, which you know now is the backbone. It's a steroid, which is a fat that becomes what?
Testosterone and estrogen. Good. And it can also become progesterone and then cortisol. Remember that other pathway. You remember hydrophilic or hydrophobic is the fatty acid tails because they're fat, so they're nonpolar.
And then the polar heads, which is the glycerol, which is polar. So the heads on either end can touch water. This hydrophobic layer in the middle repels water.
It's nonpolar. That way the cell can control what goes in and out of it. That's called selective controlling, right? Selective permeability.
Permeable means things can go through, but they're selected. Okay, that's why your cells can do unique jobs, because they have control over what goes in and out of them. That's another reason why steroids are so powerful. cell membrane, the phospholipid bilayer, cannot control that because the steroid is fat and it can go right through and diffuse into the cell, into the nucleus, and control functionality of the DNA. It has been recorded that people who take steroids, whether they're for performance enhancement or just medicine, and they can feel the effects of the steroid within minutes.
That's how fast those steroids can get in and control your DNA. I'm going to stop here and do cell transport in another video. I wanted to introduce it and we'll pick up here in part two.