Arachidonic Acid - EK H1

[pm1]

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EK states that arachidonic acid (unsaturated fatty acid) is non polar.

That's not true right? They have to be amphipatic, once it has polar (acid) and non polar ends (carbon chain).

Thanks!

This exam is very convoluted and I am not so sure how accurate it is.. would not recommend it, as much as I like EK material.

 

[Trayshawn]

Fatty acids are, by definition, amphiphilic.

However, I believe sometimes, for such compounds, if hydrophobicity is much larger than hydrophilicity, the entire compound is just approximated to be nonpolar. Or if hydrophilicity is much larger than hydrophobicity, it is considered essentially polar.

But if both non polar and amphipathic were answer choices to this question, and they said the answer was nonpolar, than that just seems like a bad question to me.

 

[sps27]

Fatty acids are, by definition, amphiphilic.

However, I believe sometimes, for such compounds, if hydrophobicity is much larger than hydrophilicity, the entire compound is just approximated to be nonpolar. Or if hydrophilicity is much larger than hydrophobicity, it is considered essentially polar.

But if both non polar and amphipathic were answer choices to this question, and they said the answer was nonpolar, than that just seems like a bad question to me.

what is amphiphilic and amphipathic? Is that the word they use to describe water, like which can act as a base as well as an acid? Arachidonic acid, isn't this the acid in ant bites or bee stings?

 

[hockey40]

EK states that arachidonic acid (unsaturated fatty acid) is non polar.

That's not true right? They have to be amphipatic, once it has polar (acid) and non polar ends (carbon chain).

Thanks!

This exam is very convoluted and I am not so sure how accurate it is.. would not recommend it, as much as I like EK material.

Arachidonic Acid is highly non-polar, but by definition, and technically, amphipatic. The carboxylic group at the end of the carbon chain is the hydrophilic region, but is rather small compared to the 20-carbon chain (hydrophobic).

 

[gettheleadout]

what is amphiphilic and amphipathic? Is that the word they use to describe water, like which can act as a base as well as an acid? Arachidonic acid, isn't this the acid in ant bites or bee stings?

Some terminology clarification here: amphipathic (synonym: amphiphilic) describes a molecule with regions of distinct polar and non-polar character. Amphiprotic or (more generally) amphoteric describes a molecule that can act as either acid or base, such as water.

 

[sps27]

Some terminology clarification here: amphipathic (synonym: amphiphilic) describes a molecule with regions of distinct polar and non-polar character. Amphiprotic or (more generally) amphoteric describes a molecule that can act as either acid or base, such as water.

Thanks bud, I appreciate it.