Biochemistry : Fatty Acids

Study concepts, example questions & explanations for Biochemistry

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Example Questions

Example Question #11 : Lipid Structures And Functions

Increased unsaturation in a fatty acid results in __________.

Possible Answers:

no change in membrane fluidity

an increase or decrease in fluidity dependent of the temperature

decreased membrane fluidity

no change with respect to membrane fluidity

increased membrane fluidity

Correct answer:

increased membrane fluidity

Explanation:

A greater degree of unsaturation results in a disruption of van der Waals forces between fatty acid chains. This is due to the "kinks" that occur within an unsaturated fatty acid. It is easy to visualize a fatty acid membrane with kinks being less tightly packed, and therefore more fluid. This increase in fluidity is independent of temperature.

Example Question #12 : Lipid Structures And Functions

Which of the following is true of an omega-6 fatty acid?

Possible Answers:

It has six double bonds located throughout the fatty acid

It has a single bond at the sixth position, counting from the carboxyl end of the fatty acid

It has a single bond at the sixth position, counting from the methyl end of the fatty acid

It has a double bond at the sixth position, counting from the methyl end of the fatty acid

It has a double bond at the sixth position, counting from the carboxyl end of the fatty acid

Correct answer:

It has a double bond at the sixth position, counting from the methyl end of the fatty acid

Explanation:

The rules for fatty acid nomenclature state that Omega 6 means that a double bond is located at the sixth position of the fatty acid - counting from the methyl end.

Example Question #11 : Fatty Acids

Which of the following statements about lipids is incorrect?

Possible Answers:

Myristic acid is saturated with 14 carbons and 0 double bonds

Linolenic acid's nomenclature is C18:29,12

Lipid double bonds are almost always cis

None of these

Biological waxes are nonpolar esters of fatty acids and long chain alcohols

Correct answer:

Linolenic acid's nomenclature is C18:29,12

Explanation:

Linoleic acid's nomenclature is C18:29,12. Linolenic acid's nomenclature is C18:39,12,15. They both have 18 carbons but differ by one extra double bond in linolenic acid. 

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