If you're seeing this message, it means we're having trouble loading external resources on our website.

If you're behind a web filter, please make sure that the domains *.kastatic.org and *.kasandbox.org are unblocked.

Main content
Current time:0:00Total duration:7:43

Lipids as cofactors and signaling molecules

Video transcript

so sometimes I go for a pretty long bike ride and when I do that I usually end up kind of getting an ache in my lower back or or in my neck kind of from being humped over the handlebars for a really extended period of time and when I do that if it's really bothering me sometimes I take some medication for it so some meta some medication and the medication that I prefer to take would be an in said so an in said and you might have heard of some common in SEDs you might even take them to aspirin for example is an in said aspirin aspirin and ibuprofen is it's another example sometimes that's called motrin but it's the same thing i IV pro Fionn but these drugs they help reduce that ache because that egg is caused by inflammation in the muscles of my lower back and in my neck and these are anti-inflammatory drugs in fact in said stands for non-steroidal anti-inflammatory drug and part of the reason why these medications stop that ache is because they stop the production of prostaglandins so prostaglandins you see prostaglandins are lipid molecules that help signal inflammation so if I can stop these prostaglandins that I can stop the the kind of further and to some extent the past production of this inflammation and its effect on my body which would be the egg and prostaglandins that into a larger class of lipids called non-hydrolyzable lipids so remember that we broke lipids down into hydrolyzable and not hydrolyzable hydrolyzable are the lipids that can be further broken down into smaller units through hydrolysis reactions and then we have the ones that can't be so prostaglandins fit into this kind of category of not hydrolyzable lipids and we talked about how the hydrolyzable functions might include energy storage and and kind of this structural function while the the nut hydrolyzable lipids their main function revolves at least in our body around signaling so-so signals just like the prostaglandins signal this inflammation up here so I think I think I have a picture of prostaglandins that I can kind of fade in for us and this would be the prostaglandin excuse me pgi2 here but prostaglandins are probably the most notable of a group of biologically active compounds called eicosanoids so let me kind of write that in here IKOS eicosanoids and i cosiest is actually greek for 20 so these are compounds that have 20 carbons and you can you can count if you want the carbons in PGI 2 but eicosanoids are kind of famous for being local mediators which means they signal an effect kind of in their immediate environment and prostaglandins are probably the most noteworthy of these eicosanoids so an example of the effects that prostaglandins stimulate would be inflammation we covered that they also lower your blood pressure prostaglandins let's see they lower your gastric secretions they inhibit platelet aggregation but they're all there are a lot of signals or effects at least that are signaled by these prostaglandins so there are a signaling lipid now another signaling lipid that are kind of pretty famous let me pull in a picture of them are steroids so I'll write that in as well steroids so steroids are tetracycline lipid which means they have kind of four rings four cyclic rings and you can you can see this in the picture here maybe I'll get a darker color so we'd have one two three and then four rings and in each of these steroids the the four rings three of them are six membered rings and the fourth is this kind of five membered ring here they all had this this four ring structure and then they differ in their little substituents but I've already done kind of an in-depth series of videos on the structure and functions of steroids but I'll keep it brief here and just kind of mention that steroids are another non-hydrolyzable lipid and that have a have a signaling effect on our body so cholesterol would be a steroid this one right here is actually testosterone testosterone and this one is progesterone progesterone and these are examples of sex hormones in our body they signal things like puberty for example and and then you have some other steroids like like a corticosteroids cortisone and aldosterone but if you want to hear I guess a lot about steroids you should definitely check out that other playlist of videos but the last the last non-hydrolyzable kind of signaling lipid that I want to talk about are actually vitamins of fat soluble fat soluble vitamins and I suppose I misspoke a few minutes ago when I said that non-hydrolyzable lipids all have this signaling function because fat soluble vitamins really function more as as cofactors so cofactors cofactors which means that they help some enzyme in our body perform a function ourselves don't make these compounds so we have to ingest them to help these enzymes perform that perform their function and there are four fat soluble vitamins we have a d e and k and i I think I've got a picture here that I can pull in for us this one right here is a and vitamin A is also called retinol and it's needed for light sensitivity in our vision as well as kind of healthy mucous membranes it has a couple different functions in our body we have a vitamin A we also have vitamin D vitamin D helps regulate phosphorus and and calcium the tab them so deficiencies can cause a number of different bone diseases like rickets and osteoporosis and so we got a D we've got e right here vitamin E is an antioxidant that help protects our neurological function and then vitamin K at the bottom at ad E and vitamin K regulates the synthesis of proton band which helps our blood clot so a lot can cause some pretty serious bleeding issues and I don't know why it kind of sticks in my mind but a D E and K are the fat soluble vitamins and they fit into they fit into that broader category again I'm non-hydrolyzable lipids non-hydrolyzable lipids which primarily function as signaling molecules and I guess for the vitamins as cofactors cofactors as well all within kind of that big category of lipids