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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What is the thinking behind the naming of arachidonic acid?

Arachidonic acid, the double bonded fatty acid, is occasionally misrepresented as having to do with spiders (arachnids). The Wikipedia entry explains that it's instead elated to "arachis" = ...
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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....
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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 ...
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Why is hydrogen to oxygen ratio used to compare energy storage efficiency?

I came across an article that says that lipids are more efficient energy storage molecules compared to starch because lipids have higher “hydrogen to oxygen ratio”. I do not understand how “hydrogen ...
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Do lipids have a monomer or not?

My biology class and I have been on the topic of macromolecules for quite some time now. Chapter 2.3 of the Foundations to Biology Textbook says that lipids are not polymers, so they do not have ...
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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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Why do the phosphatidylserine and Phosphatidylethanolamine favor one side of the cell membrane?

Thie picture below shows that the phospholipids phosphatidylserine (PS) and Phosphatidylethanolamine (PE) are more likely to be found on the inside of cell membranes than on their exterior. Why is ...
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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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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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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, ...
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Why do the mRNA vaccines for COVID need special lipids?

I've read that the Pfizer mRNA vaccine is delivered to the cell by encapsulating the fragile mRNA into a lipid nanoparticle. However, the lipid has to be PEGylated in order to avoid immunogenecity. ...
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Types of structures formed by various types of lipid molecules

Since Phosphatidylcholine (PC) and phosphatidylserine (PS) are roughly cylindrical in shape , they tend to form flat bilayers. Phosphatidylethanolamine (PE) on the other hand is conical in shape which ...
Nikhil Verma'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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How fast do lipids on the inside and outside of a lipid bilayer exchange?

Biological membranes normally have different composition of lipids on the inside and outside (ref 1, ref 2). This is maintained both by how new lipids are added to membranes, and by specialized ...
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What is the lipid membrane of SARS-CoV-2 made of?

SARS-CoV-2 is an enveloped virus: in structural diagrams it is drawn with membrane glycoprotein (M), envelope protein (E) and spike protein (S) embedded in a lipid membrane. What specifically is the ...
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Are there any drugs that target the lipid envelope of viruses?

Many drugs go after the unique viral enzymes but do any target their lipids? Viral membranes are of course similar to the host membrane but might have a different composition and do have a different ...
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Does destroying a virus envelope make the virus inactive?

Some viruses have a lipid envelope around their protein capsid. The envelope can be dissolved with soap, but does that still leave the capsid and interior genetic material intact? If so, is the virus ...
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Why is glycerol the backbone of fat?

Fats are fatty acids joined onto the backbone of a glyercol (propane-1,2,3-triol). Why was glycerol seemingly chosen by nature to be the backbone of fats? Why can't it have been a butane -1,2,3,4- ...
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Does Rough ER (RER) produce phospholipids?

I have found out that rough endoplasmic reticulum (RER) produces membranes. Therefore it has to produce phospholipids, but I thought that the smooth ER was where the synthesis of lipids occurs. What ...
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Which lipoprotein has the highest protein content?

I know that HDLs have the highest protein/lipid ratio but know that the HDLs are very small molecules too and I couldn’t find the exact answer for this question. I mean, by amounts which of these ...
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Protein rafts over the Phospholipidic bi-layer

Does any of you know the specific name of the protein rafts that allow proteins to float over a double layer of phospholipids, (cell membrane)? I just feel there should be another name rather than ...
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What animal has fat with the highest energy density?

Fat is more energy-dense than protein and carbohydrates, it is not only an energy deposit but also an organ with many functions such as cushioning and metabolism regulations. I want to know are animal ...
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Lipid packing defect [closed]

I have been trying to understand the phenomenon of lipid packing defect, but the resources in this subject are very limited. Well, I did find some papers, but before reading papers, I want to have ...
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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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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 ...
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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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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], ...
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about lipid oxidation, does acid fatty transforms in glucose? [duplicate]

Lipid oxidation generates fatty acid and glycerol going into the bloodstream. Can they be converted into glucose by gluconeogenesis or are they turnd into ketone bodies?
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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,...
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Is a fatty acid a polymer?

From my understanding, polymers are long chain molecules containing repeating units of monomers. For example, proteins are polymers called polypeptides with repeating units of (different) amino acids....
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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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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 ...
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Apolipoprotein B48 and fat storage

Can chylomicrons formed in the intestine, with apolipoprotein B48, transport lipids to adipose cells for storage?
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How are Mono and Diglycerides metabolized without the Free Fatty Acids of Triglycerides?

Having difficulty figuring out what the body does with ingested mono and diglycerides if the usual process of TAG metabolism includes the FFA released from the TAG returning to the MAG to recreate a ...
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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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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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Are all/most/any membranes comprised of lipids from the smooth ER?

I'm attending an introductory high school course to cell biology. Based on my understanding, lipids – the building blocks of membranes – are formed in the smooth ER. Are all/most/any membranes ...
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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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Can emulsion test be used to detect phospholipids?

The emulsion test- causes a white cloudy colour when lipid is dissolved in ethanol and then water added. Can this be used for phospholipids? I am aware that they are polar so may arrange in a ...
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unsaturated fatty acids and hydrogenation [closed]

what is the need to hydrogenate unsaturated fats? When we hydrogenate the unsaturated fatty acid, we eliminate double bonds by adding hydrogen atoms, and this straightens out the natural bent shape ...
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What do sphingolipids do in humans?

I want to know the significance of sphingolipids in human. I have learnt that sphingomyelin is the most significant type of sphingolipid in human. Also that the sphingomyelin serves as a structural ...
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Is palmitic acid really that dangerous?

According to Wikipedia, "Palmitic acid is the most common saturated fatty acid found in animals, plants and microorganisms. It is also the first fatty acid produced during fatty acid synthesis and is ...
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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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Are there biochemical differences between the cell membranes of prokaryotes and eukaryotes?

I would like to know if there is any difference in chemical composition of cellular bilayer lipid membrane between eukaryotes and prokaryotes. Specifically, I would like to know about the action of ...
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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 ...
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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 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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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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