I've heard it's a steroid; in what ways does it act like a steroid? I know it's necessary for survival, but have a poor understanding of how to benefit from it... Also I've heard it's just a lipid or fat. Which is it?
There are different kinds of steroids that have different effects. Athletes are interested in the class of steroids called anabolic steroids. These will improve size, strength and will shorten the amount of time needed to recover from exercise.
Cholesterol is a steroid, but is not in the anabolic class. So you would not be able to use cholesterol as a means of improving performance or appearance.
Best in Health and Training, J. R.
Although my memory of biochem is slightly blurry i think cholesterol is the "parent" molecule of most other types of steroid hormones such as testosterone. It is in other words the basic steroid molecule (4 ring structure), which the body then modifies into other steroids.
Thanks for the replies, both informative.
Hmm.. in bio class i believe that i learned that cholesterol was a lipid, along with oils, fats, and phytolipids. The PL's containing a hydrophilic head and hydrophobic tails create the cell walls, while the cholesterol floats around in the sea of cell walls, serving various purposes.
i dont know if being classed as a lipid stops it from being a steriod tho...?
-doug-
The definition of a steroid is a molecule conferring to a specific 4 ring carbon structure arrangement as Normal alluded to; sensationalistic media however has misconstrued the term, has failed to discern between steroid types and has mislead many people into thinking that if a compound is a steroid, it must be anabolic! Clearly not the case. There are many different classes of steroids, some bearing no pharmacological effect... anabolic-androgenic steroids are the ones beneficial to athletes. Cholesterol is not anabolic-androgenic, but it IS a steroid.
HERTSWENIP, isn't that what I said?
Heehee :)
So legion, you're saying it's not a lipid or a steroid. What is it?
A separate question: What other steroids are produced naturally in the human body?
It was my understanding that cholesterol IS a lipid? (hence cholesterol being the lipid component in the phospho-LIPID bi-layer of cell membranes?) If it isn't a lipid, then what composes the lipid component of the phospholipid bilayer? You have phosphates and you have cholesterol... are you saying the phosphates are actually lipids as well? This doesn't concur with what I learned in my college biology courses, although my memory might be off. Perhaps there is a different definition specific to context on what a lipid is? I don't have any of my textbooks handy (they're in storage) so I cant reference right now, but I did look at the definition in a dictionary; it's labeled as a lipid.
AK: That'd be a long list of hormones you're asking for, since there are several different metabolites and precursors involved for each, I couldn't name all off the top of my head.
But about your bet with your sister; it's like betting on whether or not your car is fast, or blue? Two totally different things. (if I'm right) Cholesterol IS a lipid AND a steroid; it doesn't necessarily have to be one or the other. So you're both correct, no one wins this one.
I should admit my ulterior motive here, too. Last week my sister-in-law was saying cholesterol was a steroid, and I said it was a lipid. She wanted to bet me fifty bucks; I declined thinking she just might be right, but it's still an implicit hubris bet.
"Cholesterol, an important molecule in animals, is an example of the steroids. In addition to being an essential component in animal cell membranes, cholesterol is a precursor in the biosynthesis of all steriod hormones, vitamin D, and bile salts."
-McKee, T., McKee, J.R. Biochemistry: An Introduction. McGraw-Hill, 1999.
so the term "phospholipid bilayer" used in biology is an erroneous misnomer?
No, it's not an erroneous misnomer. A 'phospholipid' consists of a head with a hydrophilic, negatively charged phosphate group and two hydrophobic, fatty acid (aka lipid) tails. The phospholipid bilayer is two rows of the aforementioned phospholipids, with the hydrophilic phosphate groups on the outside and the hydrophobic lipid tails on the inside.
Cholesterol is also in the membrane, but to a much lesser extent than phospholipids. Cholesterol contributes to membrane fluidity as well as stability, and it is the precursor to all the body's steroid hormones.
Polishfighter is right in that the phospholipid membrane is composed of the lipids CALLED phosphlipids. They are seperate.
I could have sworn that cholesterol was in the lipid family, but maybe i was just remembering incorrectly because it is related to the membrane.
In any event, makes sense that it is a sterol since the name is choleSTEROL.
-doug-
ahhh interesting, thanks guys.