lecture 21 + 22 fatty acid synthesis/degradation

Question 1

how do you transport acetyl coA out of the mitochondrial matrix? in what form does it need to be?

Answer 1

citrate

Question 2

where does fatty acid sythesis occur

Answer 2

cytoplasm

Question 3

where does fatty acid degradation occur

Answer 3

mito matrix

Question 4

how does citrate get out

Answer 4

porin transporter

Question 5

what are the two products that citrate makes

Answer 5

acetyl coA and Oxaloacetate

Question 6

what happens to the acetyl coA in fatty acid synthesis? what do we make out of it?

Answer 6

malonyl coA

Question 7

whats the point of making malonyl coA?

Answer 7

activation step; carboxylating so that you can decarboxylate in the next step

Question 8

ACP (acyl carrier protein) is attached to a fatty acid instead of Coenzyme A so that

Answer 8

fatty acid synthase enzyme can recognize it

Question 9

what happens once you’ve made the activation step, malonyl coA? describe the process

Answer 9

malonyl coA, acetylcoA ; swap ACP for coA. allows fatty acid sythase to recognize them. next, the money step occurs , a condensation reaction hwere you swithc acetyl ACP and malonyl ACP –> acetoacetyl ACP and reverse OHOT reactions to build your fatty acid chain

Question 10

what reactions are the reverse of OHOT?

Answer 10

CRDR; condensation, reduction, dehydration, reduction. condensation forms ACP. reduce keto to OH, and oxidize NADPH. dehydrate to form double bond. reduce double bond to single bond, oxidize NADPH.

Question 11

what is fatty acid synthesis activated by and inhibited by?

Answer 11

activated by citrate and insulin. inhibited by low energy charge , aka high AMP . or, high amounts of palmitic acid/fats

Question 12

how are fatty acids in triglycerides made available to the rest of the cell?

Answer 12

1. hack them off their glycerol backbone, carry them thru blood via albumin
2. turn into carnitine to transport into mito matrix
3. oxidize via OHOT steps to produce acetyl coA’s , NADH, FADH2

Question 13

where does fatty acid degradation occur

Answer 13

mito matrix

Question 14

what is the activation step in fatty acid degradation?

Answer 14

Adding coA onto carboxylic acid end to form an acyl-coA raises the energy of the fatty acid . requires ATP

Question 15

describe the beta oxidation reactions

Answer 15

oxidation, hydration, oxidation, thyolysis.
oxidation produces FADH2. hydration produces l-3-hydroxyacyl CoA. oxidation produces NADH, 2-ketoacyl CoA . SH-coA comes in and breaks the bond off at the beta carbon. Adds a coA to the beta carbon. Leaves off an acetyl group. Now, fatty acid chain is 2 carbons shorter

Question 16

what are the end products of fatty acid degradation?

Answer 16

7 FADH2, 7 NADH, 8 acetyl coA’s

Question 17

what are the inputs for fatty acid synthesis?

Answer 17

8 acetyl coA’s, 7 ATP, 14 NADPH

Question 18

describe the process of ketogenesis and what ketone groups are

Answer 18

Two acetyl CoA units can be combined into acetoacetate and 3-hydroxybutyrate by the liver in a process called ketogenesis. These “ketone bodies” are water soluble and circulate in the blood. Since their structures are identical to the last steps in OHOT they serve as water soluble energy carriers. The heart uses ketone bodies and fatty acids as energy molecules over glucose.

Question 19

using these terms, arrange them in order of what occurs during fatty acid degradation:

Create NADH + H+
Transfer to mito matrix
Add CoA as clip
Create FADH2
Hydrate
Activation

Answer 19

activation
transfer to mito matrix
create FADH2
hydrate
create NADH
add coA as clip