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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 don't McDonald's fries decompose?

So I was cleaning out my car and found a McDonalds French fry. as I don't eat anything in my car I know exactly who and when this fry is a result of. The when is + 10 months old and it could pass off ...
rhill45's user avatar
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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 ...
2ub's user avatar
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11 votes
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Synthesis of Fatty Acids Longer than 16 Carbons

I understand that the human body when performing Fatty Acid Synthesis can synthesize only until C16 (palmitate). However the ER has desaturases and elongases. I know that desaturases are used to add ...
oracle300's user avatar
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9 votes
1 answer
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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 ...
ManRow's user avatar
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9 votes
1 answer
92 views

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 ...
Alex I's user avatar
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8 votes
4 answers
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Why are triacylglycerols broken down before being absorbed?

So when dietary fats are in the small intestine, they are emulsified by bile salts in order for action by lipases to occur. Lipases degrade the triacylglycerols into monoacylglycerols, ...
James Norton's user avatar
7 votes
3 answers
449 views

Why are diabetic people often overweight?

I was looking at diabetes the other day, and I noticed something strange. Lower amounts of lipase are a symptom of diabetes, as is overweightness. However, since lipase is the enzyme that breaks down ...
william44isme's user avatar
6 votes
2 answers
2k views

Can animals make their own unsaturated fatty acids?

I know that animals can't make poly-unsaturated fatty acids (PUFA) and so require them from dietary sources. For eg.Omega -3 and Omega 6 fatty acids. My questions : Can animals synthesize other ...
biogirl's user avatar
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6 votes
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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. ...
Jake Evans's user avatar
6 votes
1 answer
186 views

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 ...
Alex I's user avatar
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6 votes
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338 views

Phospholipid movement in cell membranes

What causes phospholipids to flow so quickly in cell membranes? In Biology by Cambell et al. they state that a phospholipids can travel up to 2 micrometers per second. Is that a random movement or has ...
vajra78's user avatar
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Are the brains of any herbivorous animals capable of utilising ketone bodies as an energy source?

I ask this question because earlier today I heard from a lecturer at my university that a sheep's brain cannot utilise ketone bodies as an energy source and hence with insufficient glucose supply for ...
Josh Pinto's user avatar
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5 votes
3 answers
28k views

Why do cell membranes have a lipid bilayer instead of a monolayer?

Many cells have a cell membrane composed of two layers of lipids. Why is it that they have two layers and not just one? What purpose do this arrangement serve?
Gerard's user avatar
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1 answer
3k views

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 ...
Yomal Amarathunge's user avatar
5 votes
2 answers
699 views

What is a triglyceride?

I'm confused on what a triglyceride is, from what my text book it says its a type of gylercide, then from a website it said Glycerides can be subdivided into two categories. The first group, the ...
Moon CrawlerVG's user avatar
5 votes
2 answers
6k views

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
4 votes
3 answers
3k views

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....
Bøbby Leung's user avatar
4 votes
3 answers
17k views

What are the differences between how glucagon and cortisol work to increase blood sugar?

As I understand it, both cortisol and glucagon cause an increase in blood sugar concentrations. However, I don't understand how they work differently or why they work separately. I would be very ...
Meep's user avatar
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4 votes
1 answer
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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 ...
Honey Boochie Bun's user avatar
4 votes
1 answer
112 views

What are the benefits of statins in terms of prolonging life?

Recently the UK government suggested that all adults over the age of 50, without exception, would benefit from taking statins. I have an elderly female relative who may, or may not have had a minor ...
Bob Tway's user avatar
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1 answer
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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 ...
K. Claesson's user avatar
4 votes
1 answer
147 views

Can chitosan affect the absorption of unsaturated fatty acid?

I know chitosan will decrease the absorption of fat. However unsaturated fatty acid, such as DHA, is beneficial. Does chitosan effect the absorption of unsaturated fatty acid?
346699's user avatar
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4 votes
0 answers
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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 ...
user64751's user avatar
3 votes
2 answers
3k views

Are fatty acids and glycerol lipids?

As far as I know, lipids are defined as biomolecules which are hydrophobic. Triglycerides are composed of fatty acids and glycerol and are considered lipids but, are fatty acids alone or glycerol ...
biogirl's user avatar
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3 votes
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Melting point of a fatty acid? [closed]

What factors determine the melting point of a fatty acid? Chain length The number of methylene group The ionized state of the fatty acid Its degree of saponification Its ability to alter the ...
Abigailb55's user avatar
3 votes
1 answer
2k views

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 ...
dexterdev's user avatar
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3 votes
1 answer
2k views

Why is brown fat brown?

I read in Tortora and Derrickson Anatomy and Physiology that : Another type, called brown adipose tissue obtains its darker color from a very rich blood supply , along with numerous pigmented ...
biogirl's user avatar
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3 votes
1 answer
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Fatty Acid Synthesis

I have a problem in my reasoning on the fatty acid synthesis in the human body. In the synthesis process you have this homodimer. So the synthesis starts with the transfer of a acetyl group from ...
user6812's user avatar
3 votes
1 answer
1k views

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 ...
biolomist's user avatar
3 votes
0 answers
69 views

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
3 votes
0 answers
128 views

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 ...
Podo's user avatar
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3 votes
0 answers
209 views

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 ...
Polisetty's user avatar
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3 votes
0 answers
67 views

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 ...
Polisetty's user avatar
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3 votes
1 answer
239 views

What is inside IDL (intermediate density lipoproteïn)?

I am studying about the endogene lipidcycle in the human body and I know that VLDL (very low density lipoproteïn) is made in the liver and that it contains triglycerides and cholesterol from your food ...
user6812's user avatar
3 votes
3 answers
894 views

Does a reduction in stem cells mean possible earlier death?

The basis of this question relies on my understanding of these 2 facts: ...
Andrew Hall's user avatar
2 votes
1 answer
82 views

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 ...
green onion's user avatar
2 votes
1 answer
2k views

What can cause the bloating in high protein diet of Whey proteins?

I am thinking what can cause the swelling of gastrointestinal system i.e. bloating after high protein diet of Whey proteins. Liver does breaks those proteins to branched chain amino acids (BCAA), ...
Léo Léopold Hertz 준영's user avatar
2 votes
1 answer
207 views

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 ...
bar9833625's user avatar
2 votes
1 answer
112 views

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 ...
425nesp's user avatar
  • 131
2 votes
1 answer
609 views

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 ...
Laura kirkpatrick's user avatar
2 votes
1 answer
303 views

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 ...
Nomad Earthling's user avatar
2 votes
1 answer
259 views

Can Nanodiscs be used to study membrane energetics?

Nanodiscs have changed they way we can study the structures, insertion, and functions of transmembrane proteins. Below is an image of a nanodisc bilayer. The key difference, as far as I can tell, ...
James's user avatar
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2 votes
0 answers
55 views

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. ...
JunkWarrior's user avatar
2 votes
0 answers
51 views

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
2 votes
0 answers
59 views

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
2 votes
0 answers
32 views

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
2 votes
0 answers
244 views

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 ...
dexterdev's user avatar
  • 1,133
2 votes
0 answers
37 views

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, ...
Jimmy Widdle's user avatar
2 votes
0 answers
48 views

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 ...
Bayan's user avatar
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2 votes
0 answers
911 views

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