Lipid Vitamins: Study with Video Lessons, Practice Problems & Examples

Lipid vitamins, also known as fat-soluble vitamins, include A, D, E, and K, essential for various bodily functions. Vitamin A (retinol) is crucial for eyesight, derived from beta carotene in carrots. Vitamin D regulates calcium and phosphorus metabolism, requiring sunlight for activation. Vitamin E (alpha tocopherol) acts as an antioxidant, protecting against free radicals and potentially preventing cancer. Lastly, vitamin K is vital for blood clotting, with kale being a rich source. Understanding these vitamins is key for maintaining health and preventing deficiencies.

Lipid Vitamins

In this video, we're going to begin our lesson on lipid vitamins, but first, let's revisit our map of the lesson on lipids down below. And so, of course, in our previous lesson videos, we've already discussed the fatty acid-based lipids and we're currently discussing the isoprenes and isoprenoids. So, in our previous lesson videos, we've already discussed the terpenes and terpenoids, steroids, and steroid hormones. And so, here in this video, we're going to introduce the lipid vitamins. But first, what are vitamins anyway? Well, vitamins can be defined as essential compounds that are required in the diet in very small amounts since the organism can't actually synthesize those vitamins. Now, really, there are 2 general classes of vitamins that you should be familiar with. There are fat-soluble vitamins, which are otherwise known as lipid vitamins, and then there are also water-soluble vitamins. Now, moving forward in our course, we're mainly going to be focusing on the fat-soluble vitamins or, in other words, the lipid vitamins. And so, when it comes to the lipid vitamins, really there are 4 lipid vitamins, and those lipid vitamins are vitamins A, D, E, and K. And so, vitamins A, D, E, and K, which are the lipid vitamins, are all isoprenoids which is exactly why the lipid vitamins are showing up in this region of our table underneath the isoprenoids. And so, one way to help you remember the lipid vitamins is to use the memory tool, 'ADEK'. And so, vitamins A, D, E, and K sound like a deck of cards. And so here we have a deck of cards to help remind you of these lipid vitamins A, D, E, and K. And also down below right here, we're showing you some playing cards as well to remind you that the lipid vitamins include vitamins A, D, E, and K which spells ADEK. Now, these lipid vitamins, vitamins A, D, E, and K perform a wide variety of different functions and these functions are not really related to membrane structure. And so, as we move forward in our course, we're going to talk about each of these different lipid vitamins, A, D, E, and K in their own separate videos starting with vitamin A. And so, I'll see you all in our next lesson video to talk more about vitamin A.

Vitamin A

In this video, we're going to talk about our first lipid vitamin, which is vitamin A. Now, it's important to note that vitamin A is also commonly called retinol. And so, retinol and vitamin A are referring to the same molecule. Now, vitamin A is an isoprenoid lipid vitamin that's critical for proper eyesight. And so, you can see we've got these eyeballs over here to help remind you that vitamin A is important for eyesight.

And that's because vitamin A is actually required to form a light receptor protein in our eyes called rhodopsin. And so, rhodopsin is this light receptor protein found in specific cells of our eyes called rod cells. And, also, vitamin A is derived from the precursor molecule called beta carotene, which as its name implies, is a terpenoid abundant in carrots. And so, if you take a look at our image down below, notice over here what we have is the beta carotene molecule and these carrots over here. And that's because, again, the carrots contain a lot of beta carotene.

And beta carotene is the precursor molecule for our vitamin A over here or our retinol molecule, which we have boxed in right here. And, you can clearly see that beta carotene and vitamin A are both isoprenoid lipids because you can see these isoprene units embedded in their structures, and so that’s important to note. Now as we mentioned up above in our lesson, vitamin A is required to form the light receptor protein called rhodopsin. And so here we have the light receptor protein rhodopsin, and this light receptor protein rhodopsin is found in specific cells of our eyes, allowing us to have good eyesight. And so, if you eat your carrots, you’ll end up getting good eyesight, and that's a common thing that is known about carrots, that carrots allow you to develop good eyesight.

And so, this here concludes our introduction to vitamin A and retinol. And in our next lesson video, we’ll be able to talk about our next lipid vitamin which is vitamin D. So, I’ll see you guys there.

Vitamin D

In this video, we're going to talk about our second type of lipid vitamin, which is vitamin D. Now vitamin D is another isoprenoid lipid vitamin, but this time it's actually critical for regulating calcium and phosphorus metabolism. Vitamin D requires ultraviolet light, usually from the sun, in order for its formation and activation. And so it's important to be able to get a little bit of sunlight in order for your bodies to generate vitamin D. Vitamin D is ultimately going to increase calcium absorption in our bodies, leading to calcium uptake by our bones, and this allows us to get strong and healthy bones. And so, vitamin D is associated with strong bones.

Vitamin D is also derived from the precursor molecule cholesterol. In our previous lesson videos, we've seen cholesterol act as a precursor for a lot of other molecules. Once again, cholesterol is going to be a precursor for vitamin D. If we take a look at our image down below, notice on the far left we're showing you the cholesterol precursor molecule. In order for our bodies to convert cholesterol into vitamin D, a process that requires ultraviolet light usually from the sun, essentially it requires sunlight. Vitamin D then increases calcium absorption in our bodies and allows us to obtain strong, healthy bones, like what we see over here. This here concludes our introduction to vitamin D, and in our next lesson video, we'll be able to talk about our third lipid vitamin, vitamin E. So, I'll see you guys there.

Vitamin E

In this video, we're going to talk about our 3rd type of lipid vitamin, which is vitamin E. Now it's important to note that vitamin E is also commonly referred to as alpha-tocopherol. And so vitamin E is another isoprenoid lipid vitamin. But this time, it's going to serve as an antioxidant. And you might recall that antioxidants remove highly reactive and dangerous free radicals. And so what helps me remember that vitamin E serves as an antioxidant is that antioxidant literally says the letter E in it when you say it, antioxidant. And so as an antioxidant, vitamin E is going to protect other compounds from these highly reactive, dangerous free radicals. And because these free radicals can cause cancer to develop, vitamin E is also important for helping to prevent cancer. So vitamin E has a very important protective function.

So if we take a look at our image down below right here, notice that we're showing you the chemical structure of vitamin E, and so we can put in E here for vitamin E. And we know that vitamin E is also commonly referred to as alpha-tocopherol. And so notice that we're associating this shield right here with the chemical structure of vitamin E. And that's because vitamin E serves as a protective antioxidant that removes highly reactive and dangerous free radicals. And so notice down below in our image, we're showing the free radicals here as this angry They are highly reactive and dangerous. And They are highly reactive and dangerous, and free radicals can actually cause cancer in cells. And so notice down below in our image that we're actually showing you some free radicals here with, the unpaired electron, the lone pair of electron here, on these, structures that you see here.

And so hopefully, this angry mob of free radicals will remind you of the free radicals that are highly reactive and dangerous. And we really need protection from these free radicals, and that is exactly what vitamin E serves to do, with, this shield here, protecting from these free radicals as an antioxidant. And so really this here concludes our lesson on vitamin E or alpha-tocopherol. And in our next lesson video, we'll be able to introduce our last lipid vitamin, which is vitamin K. So I'll see you guys there.

Vitamin K

In this video, we're going to talk about our 4th and final type of lipid vitamin, which is vitamin K. Now, vitamin K is another isoprenoid lipid vitamin. But this time, it's going to be critical for regulating the blood clotting process, which is helpful to heal an injury. Now the name vitamin K was actually derived from the Danish word "coagulation," which was spelled with a K, and that corresponds with the English word "coagulation," which, of course, means 'clotting.' And so that goes to show that vitamin K is critical for the blood clotting process. And so, if we take a look at our image down below, notice over here, we're showing you the structure for vitamin K. And notice that vitamin K is indeed an isoprenoid lipid vitamin, which means that it's derived from isoprene units like the one that we have highlighted here. Now, notice that this vegetable that we're showing you here is kale, and kale, which also starts with a K like vitamin K, is high in vitamin K. And so by eating kale, you can get vitamin K. And again, vitamin K is critical for the blood clotting process that we see here, which helps to heal an injury. And so this here concludes our introduction to vitamin K. And so I'll see you guys in our next lesson video where we'll get to recap all of our lipid vitamins. So I'll see you guys there.

Recap of Lipid Vitamins

In this video, we're going to do a brief recap of the lipid vitamins or the fat-soluble vitamins. Recall from our previous lesson videos that in order to remember the lipid vitamins, all we need to do is think about a deck of cards. Notice here we're showing you an image of a deck of cards and notice that a deck is spelled A, D, E, and K. If we can remember that, then we'll be able to remember that the 4 lipid vitamins are vitamins A, D, E, and K. Notice over here what we have is a table with a brief description of the functions for each of these lipid vitamins.

Recall from our previous lesson videos that vitamin A serves as the site of the primary photochemical reaction in vision. It's very important for developing good eyesight. Notice that we have a picture of a carrot here to remind you that carrots are a high source of beta-carotene and beta-carotene is the precursor for Vitamin A. We also have an image of the eye to remind you that again vitamin A is important for the development of good eyesight or good vision.

Also recall from our previous lesson videos that vitamin D is important for regulating both calcium and phosphorus metabolism. Vitamin D relies on ultraviolet light or UV light from the sun for its formation and activation. Vitamin D is going to be regulating calcium absorption and therefore it will help with the development of strong and healthy bones.

Next, we have vitamin E and recall that vitamin E is going to serve as an antioxidant. It is going to serve as an antioxidant in order to prevent cancer. It is able to essentially protect from free radicals and here what we have is a shield to remind you that vitamin E serves a protection function from these free radicals.

Last but not least, we have Vitamin K and recall that Vitamin K has an important regulatory function in blood coagulation or blood clotting, if you will, or blood clumping. Recall that kale is a good source of vitamin K and here what we have is just an image of the bloodstream to remind you that vitamin K is important for blood clotting.

This here concludes our brief recap of the lipid vitamins and we'll be able to get some practice applying all of these concepts as we move forward. So I'll see you all in our next videos.

Which of the following is not a fat-soluble lipid vitamin?

• A. Vitamin K.
• B. Vitamin D.
• C. Vitamin A.
• D. Vitamin B.
• E. Vitamin E.

What is another name for Vitamin A?

• A. Vitamin B.
• B. Carotene.
• C. Retinol.
• D. α-Tocopherol
• E. Rhodopsin.
• F. Isoprene.

Severe deficiency in which vitamin could lead to blindness?

• A. Vitamin H
• B. Vitamin C.
• C. Vitamin K.
• D. Vitamin E.
• E. Vitamin A.

Severe deficiency in which vitamin could lead to rickets, a disease characterized by weakened, brittle bones?

• A. Vitamin C
• B. Vitamin D.
• C. Vitamin A.
• D. Vitamin K.
• E. Vitamin E.

Two well-known anticoagulants, dicumarol & warfarin, inhibit function of which of the following vitamins?

• A. Vitamin K
• B. Vitamin E.
• C. Vitamin C.
• D. Vitamin A.
• E. Vitamin B.

Here’s what students ask on this topic:

What are lipid vitamins and why are they important?

Lipid vitamins, also known as fat-soluble vitamins, include vitamins A, D, E, and K. These vitamins are essential for various bodily functions. Vitamin A (retinol) is crucial for eyesight and is derived from beta carotene found in carrots. Vitamin D regulates calcium and phosphorus metabolism, requiring sunlight for activation, and is vital for strong bones. Vitamin E (alpha tocopherol) acts as an antioxidant, protecting against free radicals and potentially preventing cancer. Lastly, vitamin K is essential for blood clotting, with kale being a rich source. Understanding these vitamins is key for maintaining health and preventing deficiencies.

How does vitamin A contribute to good eyesight?

Vitamin A, also known as retinol, is crucial for proper eyesight. It is required to form a light receptor protein in our eyes called rhodopsin, which is found in rod cells. Rhodopsin allows us to see in low-light conditions. Vitamin A is derived from beta carotene, a terpenoid abundant in carrots. Consuming foods rich in beta carotene can help maintain good vision by ensuring an adequate supply of vitamin A.

What role does vitamin D play in bone health?

Vitamin D is essential for regulating calcium and phosphorus metabolism, which are critical for bone health. It increases calcium absorption in the intestines, leading to calcium uptake by bones, thereby promoting strong and healthy bones. Vitamin D requires ultraviolet light from the sun for its formation and activation. Therefore, getting adequate sunlight exposure is important for maintaining optimal vitamin D levels and bone health.

How does vitamin E function as an antioxidant?

Vitamin E, also known as alpha tocopherol, functions as an antioxidant by removing highly reactive and dangerous free radicals. Free radicals can cause cellular damage and contribute to the development of cancer. By neutralizing these free radicals, vitamin E protects other compounds in the body and helps prevent cancer. This protective function is crucial for maintaining overall health and preventing oxidative stress-related diseases.

Why is vitamin K important for blood clotting?

Vitamin K is essential for regulating the blood clotting process, which is crucial for healing injuries. The name 'vitamin K' is derived from the Danish word for coagulation, which means clotting. Vitamin K activates proteins that are necessary for blood clot formation, helping to prevent excessive bleeding. Foods like kale are rich in vitamin K, making them beneficial for maintaining proper blood clotting functions.