Now, steroids are lipids that contain the steroid nucleus. Now, if we talk about the steroid nucleus, that is where we have three cyclohexane rings and one cyclops ring fused together. If we take a look here, this gives us these four rings that are fused together overall. And remember when we're looking at lipids, lipids are broken down into fatty acids with its continued breakdown into these four different groups. And then we also have our steroids, which is where we're concerned with. Now that are broken down into cholesterols, bio acids and steroid hormones, they all have this nucleus involved because they're all steroids. Now, if we look at the numbering, we're gonna say rings are designated ABC and D and numbered in alphabetical order. If we take a look here, we have ABC and D, we start off with carbon one and we move this way, we can see that the line, the, the color gets more intent as we reach the end when we get to 10 here. And then what we do is we then continue to 11 here. It's going to take this path again, it's trying to count to a carbon number 17 and as it does, the color intensifies to more red. So this is giving us highlighting a path in how we number this particular structure from carbon one all the way to carbon 17. Remember, this represents our steroid nucleus. It's essentially three cyclohexane rings connected with one cyclops ring and they're all fused together.
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Steroids Concept 2
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Now, here we're gonna take a look at cholesterol. We're gonna say cholesterol is the most abundant steroid in the human body. Remember because it is a type of steroid, it will have the steroid nucleus. We have our four fused rings together. Remember if we're gonna number this, we start out here with 123456789. And then this here would be 10. Then we'd have here 1112, 1314, 1516 and 17. Based on the numbering, we're gonna say that the oh group is a carbon number three. As we can see here, we're gonna say we have a double bond that starts at carbon number five C five. We have two methyl groups at carbons 10 and 13. So here goes a methyl group on carbon 10 and one on 13. And then we have a hydrocarbon chain at carbon 17, which is this chain right here. Now, we're gonna say that cholesterol helps maintain the structural integrity of the cell membrane. It can help with the rigidity of the cell membrane based on the amount of cholesterol that's within that cell membrane. We're also going to say here that it is the precursor of bio salter acids and steroid hormones. All right. So, keep this in mind when we're discussing cholesterols, which are part of steroids.
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Steroids Example 1
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In this example, it says explain why cholesterol is a lipid but does not undergo saponification with aqueous space. Remember with Suon application, what are we trying to do? We're trying to cut a fatty acid that we've seen before in the past into Glycerol and its salts of fatty acids. If we take a look here, the cholesterol molecule is decomposed under strong basic conditions. No, that would not be a a valid reason of why it does not undergo suppo application. Cholesterol can only be hydrolyzed under acidic conditions. Again, that would not be the correct answer why pom application will not happen with cholesterol. The side chain of the steroid skeleton is very, very stable and does not undergo hydrolysis. So yes, we have a alkyl chain on carbon number 17. So that tends to make it more nonpolar but it doesn't necessarily have to do with stability or not being under be able to undergo hydrolysis. The best answer here is D cholesterol is not a fatty acid ester that undergoes hydrolysis. Remember what's the whole point of hydrolysis in basic hydrolysis or? So, pod application it is to sever ester linkages in the formation of a glycerol molecule and salt of fatty acids because cholesterol does not represent a fatty acid ester. We wouldn't have this type of cleavage going on with a pod application. So that's why d is the best answer out of all the options provided.
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Steroids Concept 3
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Now, the next group of steroids that we'll take a look at are our bile acids. Now, they're synthesized in the liver from cholesterol and stored in the gallbladder. Here, they're going to emulsify lipids in the small intestines and increase their surface area for digestion. Now, here we're talking about emulsifying agent. This helps a hydrophobic substance to remain dispersed in an aqueous medium. And we're gonna say here, emulsifying agents can have nonpolar as well as polar regions in their structures. If we take a look here at some types of bile acids, we're gonna say this first structure. Again, it has its steroid nucleus with the four few cells, but we have a couple of groups that are highlighted here. For instance, we still have the oh on carbon three. we have now the presence of this. Oh this oh and then we have a slightly altered LKE group here. We're going to say here uh bile acids are also referred to as bio salts because they exist as anion in the intestinal ph because it exists as a salt. This would be a carboxylate anion here as well as here. Next, we have chic acid for this region. This one is just a modified version of it where it has, it's called a Chino deoxycholic acid deoxy because it's lost in oxygen. Um We see that we had an oh here, but now it's no longer there. And then finally, we have our glyco folic acid, we're gonna say here, we have glycine as the new group that's attached here. So be o negative. And what's important here is that bio aids help in the absorption of cholesterol. So that's their significance, right? So just remember these are the important aspects of bile salts. Also bile acids. When we're talking about this type of steroid.
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Steroids Example 2
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Which one of the following statements is incorrect. About bile acids, bile acids are emulsifying agents and help in fat digestion. This is one of the key things we talked about when it comes to bios salts, they're gonna help to emulsify lipids in the small intestines and increase the surface area for digestion. Bio acids act as co enzymes for lie pieces. Nowhere. Do we mention the enzyme of lie pieces and their cooper operation with bios salts? So this would be our answer. Bio acids exist as their salts in the intestinal ph. That is true because it is basic enough that we can dep proton the cary acid portions of these bio acids converting them into bios salts. Bile acids are produced from cholesterol in the liver. Yes. And they're stored in the gallbladder. So this statement is true. The only statement here that's incorrect would have to be option B.
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Steroids Concept 4
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In this video, we're gonna take a look at steroid hormones. Now, hormones themselves represent chemical messengers that help one part of a body communicate with the other. When it comes to steroid hormones, they can be broadly classified into two groups. We have them represented as sex hormones as well as adrenal cortical steroids. Now, here we're talking about sex hormones, these control sexual characteristics and regulate muscle growth and in red, we have our adrenal cortical steroids. Well, these regulate a wide range of physiological functions. If we take a look here at this chart at different types of steroid hormones. The first three deal with our sex hormones, we have androgens which are produced within the testes. And because of that, their function is the sexual development in males and they help in the control of muscle growth. A good example of this would be testosterone. Now, of course, women do produce testosterone as well or females produce testosterone as well, just not to the same extent on an average basis. Now, estrogens, these are produced within the ovaries. They help to control sexual development in females. Good example of this is estradiol. Notice the subtle differences in the structures. All of these are steroid hormones and because of that, they're gonna have our steroid nucleus where we have our four fused rings. Differences comes with what's attached to those four fused rings. Next, we have progestins. These are also produced within the ovaries and here they control the menstrual cycle and pregnancy in females. Good example, here is progesterone. Next two we have are our adrenal corticosteroids. We have glucocorticoids. So these are produced in the adrenal glands. Glucose helps to regulate glucose metabolism. And another important feature is that it helps to reduce inflammation. Good example of this is cortisol. Next, we have mineralocorticoid. So these are also produced within the adrenal glands help they help to regulate the balance of sodium and potassium ions in cells and in body fluids. Here we have our drome as the best example in terms of this type of adrenal corticoid steroid. Now here are memory tools, one and two memory tool. One deals with our sex hormones and it is Andy Tess Strange program and dand stands for androgens which are produced within the testes. The female version of that would be estrogen. So you have androgens in males, estrogen in females. And then program here would be our progestins here and again, the most common one would be progesterone memory to two is glucose control and mineral doses. Glucose control deals with glucocorticoids. Remember they help with the regulation of glucose metabolism and inflammation and then mineral doses, mineral because of mineralocorticoid. And then here we have a L DS aldosterone is the common example used for mineralocorticoid. So we utilize these two memory tools to help us group together the sex hormones versus the adrenal corticoid steroids and helps us to remember the names that exist within each of these two groups.
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Steroids Example 3
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Here. It says which one of the following statements is an incorrect description of a function of a steroid hormone. First, we have cortisol is a Glucocorticoid and regulates glucose metabolism. Yes, cortisol is indeed a Glucocorticoid from the name it deals with glucose and it does help with the regulation of its metabolism. Aldosterone helps to maintain the balance of sodium and potassium ions. Memory to two tells us glucose control and mineral doses from the portion of mineral doses. We're referencing aldosterone. Aldosterone is a mineralocorticoid. It does help with the maintaining of sodium and potassium ions within the cell and the surrounding fluids. In C were telling us that estradiol is gonna help to stimulate the breaking down of glyco glycogen within the liver. This process deals with the breaking down of glycogen. Now, we know that estrodiol are part of estrogens, right? That's the best example for it, estrogens have more to do with the sexual development in females, not with the breaking down of glycogen within the liver. So this statement is false. Testosterone contributes to the regulation of muscle growth. Testosterone is the big example when it comes to androgens which are produced within the testes and have to do with the sexual development in males. They also deal with the regulation of muscle growth. So this statement is true. The only statement here that is false would be C estradiol does not deal with the breaking down of glycogen within the liver. So this statement is incorrect.
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Problem
Problem
Which of the following compounds is not a steroid hormone?
A
Cortisol
B
Testosterone
C
Phenazone
D
Aldosterone
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Problem
Problem
Which of the following compounds is not a bile acid?