Steroids - Online Tutor, Practice Problems & Exam Prep

Steroids are non-hydrolyzable lipids characterized by a tetracyclic structure, consisting of three cyclohexane rings and one cyclopentane ring. Their stereochemistry typically features trans configurations at ring junctions, with angular methyl groups in beta positions. Steroid hormones, including sex hormones like androgens and estrogens, regulate various physiological functions. Adrenocortical hormones, such as glucocorticoids and mineralocorticoids, manage glucose metabolism and electrolyte balance, respectively. Understanding these structures and functions is crucial for grasping their biological significance.

Steroids Concept 1

Hey everyone. So in this video we're going to take a look at our steroids. Now steroids are non-hydrolyzable lipids based on the androstane structure. If we take a look at androstane, it's this structure here that we have on the left. Now, androstane is a tetracyclic, meaning four rings, molecule with three cyclohexane rings. So we see 1, 2, 3 of them. One cyclopentane ring, and two methyl groups.

Now here, remember lipids, we have hydrolyzable and non-hydrolyzable lipids. The one that we're focusing on right now are our steroids. Steroids, again, have these four fused rings, so it's tetracyclic. Three of them are cyclohexane, one being a cyclopentane. Later on, we can break this down into cholesterol and our steroid hormones. Now, the rings are designated as A, B, C, and D. And they're numbered in alphabetical order. And we're going to say the two methyl groups at carbons 13 and 10 are numbered 18 and 19 respectively. So at carbon 13, we have 18 and at carbon 10, we have 19. So this is what we can say so far in terms of the basic steroid structure.

Steroids Example 1

In this example, let's say, explain why cholesterol is a lipid but does not undergo saponification with aqueous base. Remember, with Saponification, 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 salt of fatty acids. If we take a look here, the cholesterol molecule decomposes under strong basic conditions. Note that would not be a valid reason of why it does not undergo saponification. Cholesterol can only be hydrolyzed under acidic conditions. Again, that would not be the correct answer and why saponification 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 an alkyl chain on carbon number 17. So that tends to make it more non-polar, but it doesn't necessarily have to do with stability or not being able to undergo hydrolysis. The best answer here is that cholesterol is not a fatty acid ester that undergoes hydrolysis. Remember, what's the whole point of hydrolysis? In basic hydrolysis, or saponification. It is to sever ester linkages in the formation of a glycerol molecule and salts of fatty acids. Because cholesterol does not represent a fatty acid ester, we wouldn't have this type of cleavage going on with saponification. So that's why it is the best answer out of all the options provided.

Drostanolone propionate is a synthetic androgen that has been used to treat breast cancer. Number the carbon atoms with groups in red.

Here in this practice question, we're told that the following molecule represents a synthetic androgen that has been used to treat breast cancer. Number the Carbon Atoms with groups in red. Right. So here, this is great practice. We have our basic structure of our steroid. Remember when it comes to this, we said that this is position 1. And as we're progressing counting, we had shadings of red that got darker and darker. This was a guide to help us number this structure correctly. And actually, we're going to say, so this is 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10. And then, this is 11, and the shading got darker again. 12, 13, 14, 15, 16, 17. Remember on Carbon number 13, this Carbon here would be 18, and on Carbon number 10, this Carbon here will be 19. Now, here they're asking us to number the carbon atoms with groups in red. So if we look, what do we have? We have carbon number 2 has that methyl, carbon number 3 is a carbonyl group, and then carbon number 17 is part of this ester linkage. Right? So we'd have carbons 2, 3, and 17 for this particular practice question.

Steroids Concept 2

In this video, we're going to review our decalin molecules. So here recall that fused ring systems can either be cis or trans junctions. We're going to see here that trans fused rings are rigid and more stable than cis fused rings. If we take a look here, we have 2 ways we could draw a decalin. We have cis and we have trans. We're going to say here in cis, they're cis because both hydrogens are pointing in the same direction. In this case, up because their bonds are wedged. So to show that, I'd show one hydrogen here up, and then I would show a hydrogen here up. Here, this is trans because one is up and one is down. The way I would depict this is I'd have this one up because a wedge means up, and this one down because a dash means down. From this image, we can see that trans decalin tends to be more planar than cis but it is not going to be as planar as say Benzene is. It just happens to be relatively more planar when compared to cis decalin. Now, here with trans fused rings, they can't undergo ring flipping because of their rigidity and their stability when compared to cis fused rings. Now, here we have stereo descriptors as well where Beta here represents up and Alpha here represents down. If we take a look here, cis Decalin here, this would be Beta because we have the hydrogens up, this hydrogen up. And then this would be alpha because this hydrogen here is pointing down. These are the key characteristics that we can talk about when we're referring to the cis and trans forms of decalin.

Steroids Concept 3

Hey, everyone. So here we're going to talk about steroid stereochemistry. Now here, steroids have some characteristic stereochemical features. We're going to say rings A and B junctures are usually going to be trans, and rings B, C, and C, D are almost always trans. Trans tends to be the default when it comes to nature for steroids. We have angular methyl groups, the 2 methyl groups that are on carbons 13 and 10. Well, they're going to be beta, which means up, and they're going to be in axial position. Carbon number 3 has an OH group, if present. It can be either alpha or beta. And on carbon number 17, where we have an alkyl group, if it's present, it's going to be beta, which means up again but now equatorial. We take a look here. We're dealing with our trans alpha beta junction. So, carbon number 3, we have an OH that's going to be designated as wedged here. And then we're going to say we have our hydrogen here, which we're going to make dashed. So it's trans to this OH group. And then we're going to have, let's see. We're going to have this H here also be dashed. This H will be wedged, and this one here will be dashed. Our methyl groups we're told that are going to be beta and axial. So beta means up. And then we're also told that this one here will be up, will be wedged. How does that correlate when we draw it in a chair form? Well, here, we have our hydrogen, which will be dashed, so that's down. Then we have this one here that's dashed, that's down. This one is up wedged. This one right here. Then we have this one down. We have our R group, which is going to be up. And then our two methyl groups are up. Now, here, if we do assist, what effect does that have now? Well, here, this will be wedged. This here is still dashed. This is wedged. This is dashed. And these will all still be wedged. Here, it's now depicted in this form. So, this will be up. These are still up. This H is still up. And then this one here would be down, and this one here would be down. We're going to say here that all ring junctions in cholesterol have trans configuration, and the rigidity of cholesterol helps to maintain the strength of the cellular membranes. Alright. So, when we're talking about the stereochemistry of our steroids, this is the stereochemistry we're talking about when we're looking at it as two-dimensional planar and if we try to look at it in terms of a chair conformation.

Steroids Example 2

For this example, it says, "Based on the general stereochemical characteristics of steroids, complete the following structure. Hint, the AB ring junction is cis." Alright. So, here they gave us a huge hint because it's cis here, well, that means our methyl groups are still going to be wedged here. And then our alkyl group which is on carbon 17 is still going to be wedged. Then we're going to say here for our hydrogens, we would say that this one would be wedged still. This one here would be oops. This one here would be dashed. This one here would be wedged. And then finally, this one here would be dashed. This will represent the cis-alpha-beta junction based on what we talked about, stereochemistry of steroids. Alright. So this is the depiction we would have to have for each of these groups attached to our tetracyclic structure.

Steroids Concept 4

If we're drawing steroids, we need to realize that drawing a steroid requires knowledge of some common stereochemical features along with given information. In this example, it says, draw on the structure of testosterone using the information given below. Here, we need a carbonyl group at carbon number 3. We need a double bond between carbons C4 and C5. And, finally, a beta hydroxyl group at carbon 17. Alright. So, step 1 is we're going to start by drawing the steroid skeleton which is comprised of 3 cyclohexane rings and 1 cyclopentane ring, and we have to number all the carbons. Alright. So here, we have just the skeletal outline of this. Alright. So here is our structure to begin. And if we wanted to number this structure, right, we'd say that this is 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10. And this would be, it is going to be here. If we wanted to continue counting, we have to go to the other side here. So now, this would be 11, 12, 13, 14, 15, 16, 17. If there were alkyl groups attached to 17, then that would be carbon 18. If there's an alkyl group attached to carbon 10, that would be 19. Alright. So this is our numbered structure. Now we're gonna go to step 2 here. It says draw the 2 methyl groups at Carbon 13 and carbon 10 using wedges. Remember, wedges here would mean up which mean they take on the beta configuration. So here, let's add that in now. We're using the top one as a reference. Alright. So carbons 13 and 10, well, actually, it would be carbons 13 and 10 where we would go, 18 and 19. So here, we're gonna say here let's see. We have to add 2 methyl groups. So one here, wedged, and one here, wedged. Alright. So for C13, this would be carbon 18 and 19 respectively. Now, next, we have to draw the C5 hydrogens using dashes or we have trans alpha beta junction unless otherwise stated. Alright. So we're gonna continue drawing. So at C5 we have our hydrogen which is going to be dashed. Then next, moving right from C10, we have our methyl group. We're gonna draw hydrogen atoms on the junction as alpha which is down, beta which is up, and then alpha which is down again. So coming back up here, we're going to do that. Alright. So C10, moving right from C10, right from C10. We're gonna have here carbon 9. There's gonna be an H that's dashed for alpha and then one that's up for beta, and then one that's dashed for alpha. So that's what we have so far. And again, these are our methyl groups. Now, fill in all the given information to complete the structure. Alright. So we're told that carbon number 3 has a carbonyl group. So here goes our carbonyl group. Carbons 4 and 5, well, they're gonna have a pi bond, which would mean I have to get rid of this hydrogen here because carbon can't make more than 4 bonds. And then it told us what else? Oh, a beta hydroxyl OH group on carbon number 17. So beta would mean that it's pointing up. So there goes the OH, and it's pointing up. So this would be the structure. We drew out the base steroid skeletal structure, and from there, we added the, essentially, the modifications from the example question itself. We added a carbonyl group on carbon 3, a pi bond between carbons 4 and 5, and then finally, a beta hydroxyl on carbon number 17 to give us this final depiction of our compound.

Which one of the structures given below fulfills the given criteria?

1) Ketone at C3.

2) Double bond between C4 and C5.

3) An –OH group at C17 in β configuration.

4) A –CH₃ group at C17 in α configuration.

• A.
• B.
• C.
• D.

Draw the structure of metenolone from the information given below:

1) A –CH₃ group at C1.

2) A double bond between C1 and C2.

3) A ketone at C3.

4) An acetate group at C17 in β configuration.

In this practice question, it asks to draw the structure of metal no loan, based on the information provided. First, we need to draw the tetracyclic structure for our steroid, which includes three cyclohexanes. Next, we should number them as follows: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, and continuing onto 11, 12, 13, 14, 15, 16, and 17. According to the question, we have a methyl group on carbon 1. Therefore, a methyl group is positioned on carbon 1. There is a double bond between carbons 12, which is significant because it means we do not need to give stereochemistry to the methyl group we just added on carbon 1. A ketone is placed on carbon 3, indicated by a carbonyl group there. Additionally, there is an acetate group at carbon 17 in the beta configuration. To depict this, the beta configuration means the group is wedged, including an oxygen linked to the acetate group. However, this isn't yet complete because we technically need to draw the stereochemistries of other groups attached. We would have a methyl group on carbon 10 and 13, which are wedged. There is also a hydrogen that is dashed. Moving to carbon 10, to the right of it, we have an alpha hydrogen, which is down, and a beta hydrogen, which is up, followed by another alpha hydrogen down. This detailed description represents our complete structure based on the four criteria and based on the baseline skeletal structure of a given steroid. This is deemed the final answer for the structure as described.

Draw the structure of the product formed when fluoxymesterone undergoes reduction with LiAlH₄.

• A.
• B.
• C.
• D.

Steroids Concept 5

Hey everyone. So in this video, we're going to take a look at our steroid hormones, and in particular, our sex hormones. Now, hormones themselves represent chemical messengers that help one part of a body communicate with the other. We're going to say they can be broadly classified into two groups. We have our sex hormones and then we have our adrenocortical hormones. Sex hormones control sexual characteristics and regulate muscle growth. Male sex hormones are our androgens, and female sex hormones are our estrogens and our progestins. Now here we have our hormones, where they're produced, their functions, and some examples. With androgens, they're produced within our testes and because of that, we're going to say the function is to control sexual development in males and also to control muscle growth. Here we have two great examples of them with testosterone, probably being the most popular of the two. Next, we have estrogen which is produced within our ovaries. They control sexual development in females. Here we have our two examples of them. And then we have our progestins which are also produced within our ovaries. They control the menstrual cycle and pregnancy in females. And then here we have progesterone as the one lone example. Now, estrogens are characterized by an aromatic ring A and a missing methyl group at Carbon 10. Remember Carbon 10, we don't have that methyl group that we typically tend to see with the basic skeletal structure of a steroid. Now, here on memory tool 1, to help us remember this, is we're going to say, 'Esters have aroma.' Esters, estrogens, and then we're going to say 'have androgens,' and then we're talking about aroma, progesterone, progestins, and estrogens are closely linked together. That helps us to remember what are the three hormones that fit under sex hormones. Right. So just remember, we're talking about steroid hormones. This is just one of the two broad categories for our steroid hormones.

Steroids Concept 6

In this video, we're going to take a look at our adrenocortical hormones, which is our second category of steroid hormones. They basically regulate a wide range of physiological functions. Here, when it comes to these hormones, there are two types; we have our glucocorticoids and our mineralocorticoids. The first one is produced within our adrenal glands and regulates glucose metabolism and reduces inflammation. For example, we have cortisol. Our mineralocorticoids, which are also produced within our adrenal glands, regulate the balance of sodium ions and potassium ions in cells and body fluids. This is incredibly important. If you have these ions out of balance, it can lead to some serious deleterious effects on the body. Now, here we have aldosterone as the example of this type of adrenocortical hormone.

From the images, we can note some things. We have this OH group that's present in both. We're going to say all adrenocortical hormones or steroids have an OH group at carbon 11. And then, our memory tool here is we can say, "Adriana," we're going to say, "hydrates 11 times." Right? So here, 'Adriana Adrenocortical,' we're going to say it hydrates 11 times. So, we are talking about fluids here. We are talking about minerals. This is what we are discussing to help us remember these two types of hormones within this section or category of steroid hormones.

Steroids Example 3

Here it says, "Which one of the following statements is correct about steroid hormones?" Here, testosterone molecules do not have the C₁₉ methyl group. If you go back and take a look at our testosterone, we see that indeed it does have a methyl group, and that methyl group is on carbon 10, but it'll be numbered carbon 19. So, this is false.

All adrenocortical hormones have an OH group at carbon 10. No, that is not true. What they have instead of an OH group there is a methyl group. It's on carbon 11 where they have an OH group. The methyl group at carbon 10 is not present in estrogens due to the aromatic ring A. That is true because of the presence of that aromatic ring; that carbon will be making too many bonds if it still had that methyl group. So, option C is correct.

And then here, the ring A in progesterone is aromatic like esterone. Esterone is an estrogen. They have aromatic rings for ring A, but progesterone is a progestin; they do not have an aromatic ring A. So, this is not true. The only option here that's true would have to be option C.

Classify dexamethasone into one of the steroid hormone classes.

• A. Androgen
• B. Estrogen
• C. Progestin
• D. Adrenocortical hormone

Oxymetholone is used to treat anemia and to promote weight gain and muscle growth. Based on this information, classify oxymetholone into one of the three classes of sex hormones.

• A. Androgens
• B. Estrogens
• C. Progestins

Here’s what students ask on this topic:

What is the basic structure of steroids?

Steroids are non-hydrolyzable lipids characterized by a tetracyclic structure, consisting of three cyclohexane rings and one cyclopentane ring. This structure is based on the Androstane skeleton. The rings are labeled A, B, C, and D, and are numbered in alphabetical order. The two methyl groups are located at carbons 10 and 13, and are numbered 18 and 19, respectively. This tetracyclic structure is crucial for the biological functions of steroids, including their role as hormones.

What are the differences between cis and trans ring junctions in steroids?

In steroids, ring junctions can be either cis or trans. Trans ring junctions are more stable and rigid compared to cis junctions. In trans junctions, the substituents on the ring junctions are on opposite sides, making the structure more planar. In contrast, cis junctions have substituents on the same side, leading to a less stable and more flexible structure. Most natural steroids have trans ring junctions, contributing to their rigidity and stability.

What are the main types of steroid hormones and their functions?

Steroid hormones are broadly classified into two categories: sex hormones and adrenocortical hormones. Sex hormones include androgens (e.g., testosterone) and estrogens (e.g., estradiol), which regulate sexual characteristics and reproductive functions. Adrenocortical hormones include glucocorticoids (e.g., cortisol), which regulate glucose metabolism and reduce inflammation, and mineralocorticoids (e.g., aldosterone), which manage electrolyte balance. These hormones play crucial roles in various physiological processes.

How do you draw the structure of testosterone?

To draw the structure of testosterone, start with the basic steroid skeleton, which includes three cyclohexane rings and one cyclopentane ring. Number the carbons from 1 to 17. Add a carbonyl group at carbon 3, a double bond between carbons 4 and 5, and a beta hydroxyl group at carbon 17. Ensure the two methyl groups at carbons 10 and 13 are in the beta (up) position. This will give you the complete structure of testosterone.

What is the role of adrenocortical hormones?

Adrenocortical hormones are a category of steroid hormones produced by the adrenal glands. They are divided into glucocorticoids and mineralocorticoids. Glucocorticoids, such as cortisol, regulate glucose metabolism and reduce inflammation. Mineralocorticoids, such as aldosterone, manage the balance of sodium and potassium ions in cells and body fluids. These hormones are essential for maintaining homeostasis and responding to stress.