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Bridgewater State University
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Evoution connection A typical prokaryotic cell has about
$3,000$ genes in its DNA, while a human cell has almost $21,000$
genes. About $1,000$ of these genes are present in both types of
cells. Based on your understanding of evolution, explain how such different organisms could have this same subset of $1,000$ genes. What sorts of functions might these shared genes have?
Which of the following best demonstrates the unity among all
(A) emergent properties
(B) descent with modification
(C) the structure and function of DNA
(D) natural selection
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In this video, we will discuss lipids. So what are lipids? While lipids are going to be a wide range of different hydrophobic molecules that are all group together based on one property and one property only, the fact that they do not like to mix with water so they are going to be hydrophobic molecules that will not want to interact with water. And this is all because they are extremely large and non polar. And of course, there is going to be a wide variety of these lipids. They're going to be fats, and there will be fossil lipids as well as steroids. And we'll go through each type of lipid just to discuss how it's structured, what it looks like and what function has within our bodies and within biological systems in general. So let's start off with Fats and fats will be also known as try asshole glycerol, ALS and these try asshole glycerol will draw out the structure of them in a moment here, but they will consist of three fatty acid chains, plus a glycerol. We'll show how these fatty acids will attach to the glycerol to form our fat molecule. So we have our glycerol right here on the glycerol consists of three carbons with hydrogen on the left hand side here and ohh groups or hydroxy groups on the right hand side. And the importance of these hydroxy groups is very high because they will function in allowing for fatty acids to join this glycerol. So, like we said, this is going to be in glycerol right here. That's our glycerol. And then our fatty acid will basically be a very, very long chain of these carbons that will either be ah, single, bonded or double bonded. But if we are just focus on our single bonded chains of fatty acids first, then we'll just draw them out as such. But on the very end, right here will be an O H group or a hydroxy group, and then a double bond with an oxygen. And specifically the O. H here is going to combine with the hydrogen of the O. H on the glycerol. And together these will form a water molecule and thus allow for our fatty acid to join up with our glycerol forming an Esther Bond. So then we would form this Esther Bond right here we call that an Esther linkage. And it's important to note that this right here that we have drawn out is a fatty acid, and the same would occur. Wait, like with the same fatty acids would bond to these other two carbons as well. Forming a molecule that kind of looks like like this. And that will be our try, asshole glycerol. Because we'll have our fatty acid chains right here and our glycerol right here. Now let's discuss the difference between unsaturated fatty acids and saturated fatty acids, so a saturated fatty acid will consist of single bonded carbons. So if we were to take a look at the fatty acid right here, we see that it is going to be a saturated fatty acid because it consists of Onley these single bonded carbons as evidence by everything that we've highlighted here. So these will be, uh, saturated fatty acids. However, an unsaturated fatty acid will contain double bonded carbons. So a an example of this If we were just to look at our fatty acid up here, we could add in a second bond here and let's say a second bond right here, as well as you can see Now we have made a unsaturated fatty acid because it has double bonded carbons. And this will change how our fatty acids will be arranged. And specifically, this will be an important part in our fossil lipid structure. So we'll talk about fossil lipids right here. Foster lipids are going to be these molecules that have a hydro filic head where a water loving head and a hydrophobic tail and the hydro filic head will be polar and the hydrophobic tail will be non polar and fossil lipids are going to form the fossil lipid bi layer characteristic of our plasma membranes in cells. So basically, with these plasma membranes, we have all of these hydro filic heads that stick out outside or towards the outside. So all these hydro filic heads will be on the exterior portion and then there will be these hydrophobic tails that will be on the interior of our plasma membrane, and the difference between and unsaturated fatty acid and the saturated fatty acid becomes really apparent here because, for example, this fatty acid right here is going to be saturated. How can we tell? Well, because the fatty acid chain is going to be straight. Whereas if we were to take a look at this one right here, let's draw it in. It will have a fatty acid chain that will have a kink in it. So this fatty acid here will be unsaturated. So it means that the carbons there will be double bonded and has a kink or a bend in it's fatty acid chain. So the way that the fossil lipid is structured with this fossil lipid violator is going to be extremely important in how our plasma membrane of cells is able to keep water on the outside of the cells out of the cell. And the site is all or the cytoplasm inside the cell on the interior of the south. Because as we make this fossil lipid violator, we are essentially making a waterproof barrier that will consists of all of these possible lipids on the interior here, keeping the extra cellular or outside water or environment outside of ourselves and our cytoplasm is going to be contained within ourselves. So there will be no easy exchange or no easy pathway for this water to enter because it would have to pass through this hydrophobic region right here so this will be a hydrophobic region, whereas these heads are going to be hydro filic so they will interact with the water environment on the outsides here and the interior of our plasma membrane will be hydrophobic. And finally there is going to be a class of lipids called the steroids, and it's just important to note that our steroids are going to be accounting for a lot of the hormones that we have.
Cellular Respiration and Fermentation