Questions tagged [lipids]

For questions related to lipids including but not limited to fats and their derivatives in regards to chemistry.

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2
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1answer
193 views

Why is a drop of chloroform stretched/pulled apart on a water surface?

I distributed drops of chloroform (with a lipid in them) on water (in a Langmuir-Blodgett trough). The chloroform drops form a layer on the water (so that the lipids are distributed on the water ...
7
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1answer
76 views

Prostaglandin Nomenclature

Prostaglandins are lipid substances derived from fatty acids, which act as powerful biochemical regulators. In Wade's Organic Chemistry, they indicate that there are several families of ...
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0answers
68 views

Can Lugol's iodine differentiate between saturated/unsaturated fats?

We conducted an experiment involving Lugol's iodine where if a substance contained a lipid it would form concentrated areas of color on the sides of the test tube. On many occasions, the test would ...
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0answers
27 views

Fat polymerization vs hydrolysis and temperature change

I have an experiment on fats that I have to do in a few hours and I am very lost between fat/oil (lipid) polymerization due to high temperatures and hydrolysis. It appears that both result in the ...
2
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1answer
99 views

Can you lower the alcohol concentration of a drink using vegetable oils?

The log POW of ethanol is −0.18 according to Wikipedia, i.e. in a two-phase system ethanol would preferrably accumulate in the aqueous phase, but not by much. Suppose I wanted to lower the alcohol ...
2
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1answer
104 views

Techniques to extract lipids

I am planning an experiment on how to isolate casein and part of the process involves removing any lipids that may still be in it after filtering the precipitated casein out of the milk. I have read ...
1
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1answer
1k views

What kind of plastic is (really) safe to store vegetable oil?

Storing colza or olive oil in a plastic bottle might be risky since the oil can leach out phthalates and BPA (and others molecules?). Some manufacturers sell "phthalates and BPA free bottles", but ...
4
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2answers
2k views

Is flour or baking soda really suitable for extinguishing grease fires?

I think most have heard the advise that you should put flour (or baking soda) on a grease fire to absorb the oil before. While this is certainly better than using water, I'm skeptical. For starters ...
3
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2answers
75 views

Why would diclofenac have a higher skin permeability when formulated as diclofenac epolamine rather than diclofenac sodium?

There is a suggestion on the literature that the formation of ion pairs creates a permeation enhancement. Usually only non-ionised compounds penetrate the skin. Is it possible that the conjugate ...
1
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1answer
1k views

What happens to a quaternary ammonium cation at a pH above its pKa?

I am working with a lipid and I have firm reasons to believe that its pKa is around 8. This lipid is a cationic lipid where the nitrogen is a quaternary amine with two lipid chains and two methyl ...
2
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0answers
38 views

What Makes Oils Feel Dry or Oily? [closed]

Simple question with a complex answer, certainly: Why do some oils feel "dry," while others feel "oily"? Is the feel directly related to C-chain length, or hydrogenation, active groups, or something ...
0
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1answer
804 views

Could detergents dissolve cell membranes?

Animal cells have a lipid membrane and detergents are great at emulsifying lipids. Yes, there are proteins, cholesterol and other numerous substances in the lipid bilayer, but the lipids make up the ...
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1answer
389 views

Are triglycerides macromolecules?

I've previously been taught that triglycerides are macromolecules. However, a current professor of mine gave the definition of macromolecules as "polymers of covalently linked monomers". Since, ...
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0answers
94 views

How do water based solutions (cream, gels) etc permeable through hydrophobic skin? [closed]

Most skin care products or the sort are oily, lipid based. Our skin is hydrophobic. I reckon the reason is to be easily permeable through the skin. So how do these skin care or any products which are ...
5
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1answer
387 views

Why are plastics lipophilic?

My wife prepares lunch for me every morning. After eating it on my desk, I typically wash the lunchbox and utensils in the company's kitchen. I have noticed that it is very difficult to remove the ...
2
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1answer
2k views

How are phosphoglycerides different from phospholipids?

(Currently studying high-school Biochemistry) I'm unable to distinguish between phospholipids and phosphoglycerides from their "definitions" (Courtesy: Wikipedia) On phospholipids: Which suggests ...
1
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1answer
764 views

What happens during oxidative and hydrolytic rancidity of fats?

I understand that when lipid molecules - triacylglycerol - are hydrolysed, the fatty acids 'break' off from the glycerol backbone. And when fatty acids oxidise, these in turn can break into smaller ...
0
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1answer
133 views

How well can triglycerides be resolved using TLC?

The only part of triglycerides that significantly interacts with a TLC plate are the ester moieties which are present in all triglycerides. Other than that, they do not differ much, except in mass (...
1
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1answer
195 views

What is the significance of Sphingolipids in human?

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 ...
7
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3answers
1k views

Is it known for sure that bases feel slippery because of the production of soap/surfactant?

Discussion around the question Why does bleach feel slippery? has started me thinking about the saponification explanation for the slippery feeling of basic solutions. According to Wikipedia: ...
1
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1answer
31 views

How can I know if there is a phospholipid (phosphatidylcholine) in a solution?

I have a solution which probably contains a phospholipid (phosphatydylcholine), I would like to know if there is an easy method to show the presence of the phospholipid. I came across TLC, but I ...
11
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1answer
691 views

Do unsaturated fatty acids with an odd number of carbons exist?

Our teacher asked us about fatty acid C21:3. Does this fatty acid even exist?
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0answers
1k views

Mechanism Permitting Proton Sponge Effect

The proton sponge effect is utilized as a drug delivery method to release contents packaged in micelles (usually coated in PEG or another protective polymer) into the cytoplasm of a cell after being ...
0
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2answers
5k views

Are triglycerides soluble in polar solvents?

In my textbook it is said that they are soluble in non-polar solvents (which makes sense), but also soluble in polar solvents (halogenoalkanes and some ethers like ethoxyethane) It is said that the ...
6
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1answer
317 views

What is the common denominator of all the lipids?

I've read the lipids article on Wikipedia, but I couldn't understand the answer for my question and I'll explain why. In biochemistry we have monomers and polymers while the monomer is the basic ...