CHEM 4420 Lecture 13 (Exam II)

What is the yield of ATP per carbon from beta oxidation?

6\.63/C

Why are fatty acids the fuel of choice for migratory birds?

More energy produced per carbon- more easily stored plus energy output higher

What is the last fragment of an odd-numbered fatty acid chain after beta oxidation?

propionyl-coA

If beta-oxidation requires a trans molecule for the second step (in which the trans double bond is hydrated), how are monounsaturated fatty acids with a cis double bond broken down?

Before the second step of beta oxidation, enoyl-coA isomerase converts the cis bond to a trans bond and moves the bond down by one (delta 3 to delta 1). Beta oxidation then continues.

Enoyl-coA isomerase deficiency leads to:

Non-alcoholic fatty liver disease (NAFLD), accumulation of unsaturated fatty acyl groups in ester lipids and deposit large amounts of triglycerides in hepatocytes

PUFAS naturally have double bonds that are __

cis

What does saturating a PUFA with hydrogen do?

Artificially created saturated fats = trans fats. Oils become solid at room temperature- increased plasticity. Trans fats last longer than butter without going bad

What are natural trans fats? How are they formed?

I.e. conjugated linoleic acid (CLA). Formed when rumen bacteria in cows, sheep, etc. digest grass and form trans-rumenic acid and trans-vaccenic acid. Predominant in mother’s milk

Why trans fats?

Desirable taste, shape, texture. Labelled as “hydrogenated” or “partially hydrogenated” fats

If walrus blubber is so full of fatty red meat, why is it not so bad for you?

Rich in Vitamin A, omega 3 FAs (unsaturated), omega 6 FAs (unsaturated)

What is the ideal omega 6 : omega 3 ratio for the western diet? and generally?

4:1 for Western diet; 1:1 optimal

Examples of omega 3, 6, 9 FAs:

3: ALA (alpha linolenic acid); 6: alpha linoleic acid; 9: Sunflower oil

Which of the omega fatty acids are pro-inflammatory? Which ones are anti-inflammatory?

6 is pro-inflammatory; 3,7,9 are anti-inflammatory

Why do camels have humps?

Large fat store for energy; as they break down fat for energy, water is released which they use to hydrate themselves