Questions tagged [lipids]

A broad group of consisting of biomolecules that are soluble in non-polar solvents. Most of these molecules have huge hydrocarbon chains (linear or cyclic). Examples include glycerides (glyceryl esters), isoprenoids and steroids.

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Why our body does not produce polyunsaturated fatty acids?

Our body does not produce two polyunsaturated fatty acids (PUFA): linoleic acid and alfa-linolenic acid. I am thinking reasons for it. Saturated fatty acids have more energy than unsaturated. ...
Léo Léopold Hertz 준영's user avatar
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Why do the COVID vaccines contain the cationic lipids they do?

Why did Moderna & Pfizer specifically pick their SM-102 and ALC-0315 cationic lipids with tertiary amines, branched tails, long linker chains, and small hydroxyl head groups? Are the large tails ...
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Why is it possible to render fat if it's in cells?

To the casual onlooker, fat seems like a mass of yellow-white material, composed of lipids. Biologically speaking however, rather than being a large mass, it's actually divided among countless cells, ...
TheEnvironmentalist's user avatar
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What change would you expect in phospholipid orientation of the membrane if the enviornment were mostly heptane?

The external and internal environment of the cell is basically water, thus phospholipids organize themselves the way they do (bilayer). If the environment were to magically become mostly heptane, how ...
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What is the function of CETP?

I read up that CETP transfers cholesterol from HDL, which collected it from tissues, to VLDL. This VLDL is then sent back to the tissues, ultimately forming LDL internalised by cells. What is the ...
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What is the rationale behind reverse cholesterol transport?

Reverse cholesterol transport is transport of cholesterol from the tissues back to liver/VLDL. My question is why do the tissues have this extra cholesterol in the first place? Why would you ...
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How do the lipid nanoparticles in the Pfizer and Moderna vaccines contain and release the mRNA payloads at the right time?

The engineering challenge with mRNA vaccines is that mRNA is fragile and degrades quickly. The solution, then, is to encapsulate the mRNA within lipid nanoparticles that carry the payload into cell. ...
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Osmosis/ Facilitated diffusion

Water can move across the (Semipermeable non polar lipid) membrane by simple diffusion (osmosis). But polar molecules cannot pass through the non polar lipid bilayer, they require carrier proteins to ...
Aryan Stark's user avatar
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Oil absorbed into human skin -- where does it go?

For example, I apply petrolatum to my dry hands twice a day as in winter I am usually in a 20-30% RH environment. Within an hour, the petrolatum seems entirely absorbed. According to [1], ...
Nissim Nanach's user avatar
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Lipids that are not found in human body

I know that human body contains FA some of which are essential and the other is not depending on the ability of the body to synthesize them in a sufficient amount, but I need a reference of the lipids ...
Reem M.Al Haj's user avatar
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What is the biological relevance of RIPPLE phase in membranes?

I was reading about ripple phase in bilayer lipid membranes which is described here as a meta-stable state between lamellar tilted crystalline and lamellar fluid state. It is also known that ripple ...
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How is omega 3 deficiency determined?

I read quite a bit online about omega 3 deficiency. How is this actually determined - that is, what happens in the lab to determine this ? n-3 fatty acids have roles in many different human tissues, ...
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Why do Proteins store energy when the body already contains Carbohydrates and Lipids?

We already know that lipids are a source of long term energy and carbohydrates are much faster energy releasing sources. So why do we need specific proteins within the body to store energy? Are ...
nosyminotaur's user avatar
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Lifeforms concentrations of the categories of macromolecules, and Lipids

Lifeforms are formed of large, modular, organic molecules called macromolecules, large organic molecules called Lipids, and simpler molecules such as H2O. Macromolecules are commonly grouped into the ...
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Is there a way to quantify in vivo cholesterol transport rates?

I have always had trouble grasping the physiology of lipoprotein cholesterol transport. The "standard" description found in the literature is that liver synthesizes cholesterol which is carried in "...
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Bimodal melting point of animal fats?

This could fit into Chemistry, Seasoned Advice or other SE forums. The largest number of "close" questions seems to be here; apologies if I'm in the wrong place. I've noticed when cooking ...
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Through what mechanism does ingesting Saturated Fat (but not Mono unsaturated Fat/PUFA) increase Serum Cholesterol.?

I know that the saturated fats you ingest is broken down in the intestines by the bile acids from liver and then re synthesized as triglycerides after crossing the enterocytes. Then these ...
Sanjay Biswas's user avatar
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Reference request: Lipid composition in bacterial, yeast and human membranes

I would like to know about the lipid composition of different kinds of cellular membranes. I remember going through such a table once in a paper, but I am unable to find it anymore. What I am looking ...
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Are unsaturated fats antioxidants?

Unsaturated fats contain double bonds like carotenoids (which is an antioxidant), and from my understanding, what makes carotenoid an antioxidant is that its double bonds allow it to undergo oxidation,...
Bøbby Leung's user avatar
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What happens to lipoprotein lipase after a sugar only diet?

Insulin increases the activity of lipoprotein lipase thay allows cells to take in lipids from chylomicrons in the blood. If a person takes a sugar only meal like drinking coke, insulin is released. ...
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Why Milky serum in diet rich with Triglycerides?

When we eat the meal rich with triglyceride our muscle or blood after seperation of the serum the color of the serum will be milky. What is causing to happen in our serum ? Milky serum (lipemic serum)
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If chylomicrons can not get into the capillaries, how do they supply to tissues?

The transport of chylomicrons is into the lacteals mainly because they are too big to get into the capillaries and yet they later supply triglycerides in the extra hepatic tissue by traversing in the ...
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What is the actual function of HDLs and CETP?

I know that HDLs collect cholesterol from peripheral tissues and transport it back to the liver using SRB1 - Reverse cholesterol transport and dumping it in bile. So the tissue is producing some extra ...
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Why do some people accumulate more diglycerides in their muscle cells?

The scientist Gerald Shulman has experimentally found that young lean adults in their early twenties that are children to people with type 2 diabetes often show muscle insulin resistance. He found ...
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Melting Points of Animal Fats and Body Temperature

Melting points of animal fats used in cooking vary quite significantly. In some cases being above the body temperature of the animal, and in other cases being well below (cf the examples below). Lard:...
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Lipid Bilayer composition

I am currently taking a course on introduction to biomolecules and the other day our professor showed us a photo describing the composition of lipid bilayers of various organelles in a eukaryotic cell....
Preetham Karki's user avatar
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Difference between cerebroside and globoside

I have a general idea about their difference that cerebrosides have a single sugar while globosides have more than one sugars. This is the structure of a ceramide (syphingosine and a fatty acid ...
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