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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3k views

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 ...
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3answers
380 views

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, ...
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3answers
186 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 ...
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1answer
2k 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. ...
5
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1answer
271 views

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 ...
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2answers
550 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 ...
4
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1answer
89 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 ...
4
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2answers
203 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 ...
4
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1answer
96 views

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 ...
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4answers
7k 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?
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1answer
60 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 ...
3
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1answer
166 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 ...
3
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1answer
71 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?
3
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3answers
218 views

Does a reduction in stem cells mean possible earlier death?

The basis of this question relies on my understanding of these 2 facts: ...
2
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1answer
13k views

Melting point of a fatty acid?

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 ...
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3answers
1k views

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

As I understand, 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 grateful ...
2
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1answer
924 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), ...
2
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1answer
258 views

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 ...
2
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1answer
88 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, ...
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0answers
31 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 ...
2
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0answers
28 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 ...
2
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0answers
28 views

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 ...
2
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1answer
92 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 ...
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2answers
238 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 ...
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1answer
222 views

Transverse diffusion of lipids in red blood cells

The membrane of a human erythrocyte has polarity: Phosphatidylethanolamine and phosphatidylserine are predominantly on the inner side. Phosphatidylcholine and sphingomyelin are predominantly on the ...
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1answer
41 views

How is the Concept of Simple Diffusion Possible

How can a substance pass through a lipid membrane in a cell through simple diffusion? In order for something to be able to go through the membrane, in simple diffusion, it must be hydrophobic, or non ...
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0answers
25 views

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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0answers
28 views

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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0answers
40 views

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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0answers
65 views

Nearly Exhaustive List for Cholesterol Pathways [closed]

I have run across an interesting case that is similar to only two others I've encountered. What makes it interesting is the combination of undetectable (under normal testing conditions, can elaborate ...
0
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1answer
683 views

What is the role pyruvate carboxylase in lipogenesis?

I just know that Acetyl-CoA is a positive allosteric modulator for pyruvate carboxylase, but I cannot find anything else.
0
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1answer
113 views

Which of these components has C-H and COOH groups [closed]

A) Amino acids and triglycerides that have a carbon-carbon double bond or B) proteins and fatty acids I think they ...
0
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1answer
256 views

Description of the paramaters in the packing parameter?

For a phospholipid, the critical packing parameter is given by: $$P=\frac{v}{a_0l_c}$$ And I know that $v$ is the volume of the hydrocarbon tail. $l_c$ is the critical length of the hydrocarbon ...
0
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0answers
43 views

Is it possible to measure in vivo enzyme kinetics?

I was wondering is there way in which we can measure enzyme kinetics in vivo specifically for enzymes acting on lipid substrates (where substrate is restricted to 2D membrane as oppose to freely ...
0
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0answers
16 views

phospholipid alterations in breast cancer

I'm interested in designing some experiments to assess how altering fatty acid synthesis affects phospholipid synthesis/lipid profiles. I've come across papers using standard inhibitors of FAS like ...
0
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1answer
48 views

Cell targets of Glybera

So we know that there is a first gene therapy drug in the market out there called Alipogene tiparvovec to address lipoprotein lipase deficiency (LPLD) at a genetic level. Does this genetic drug ...