Week 11

Question 1

other names for triacylglycerol

Answer 1

triglyceride, TG

Question 2

acyl vs acetyl

Answer 2

acetyl = 2 carbon chain
acyl = longer than 2 carbons

Question 3

what are the 4 steps in each round of beta oxidation?

Answer 3

1. Acyl CoA dehydrogenase → FADH2 and double bond in FA chain
2. Hydratase → adds water across double bond
3. Dehydrogenase → NADH and keto group on beta C
4. Thiolase: uses CoA to release acetyl CoA from beta keto acid → fatty acyl CoA chain w/ 2 less carbons

Question 4

where does the product acetyl CoA go after beta oxidation?

Answer 4

enters CAC

Question 5

why is it important to have various fuels?

Answer 5

CAC is dependant on presence of OXA which can be made from pyruvate from glucose or glycogen but cannot be made from acetyl CoA from fat catabolism

Question 6

why are 2 ATP required for FA activation?

Answer 6

1 for thioester bond formation
1 for regeneration of 2 ADP from 1 AMP and 1 ATP

Question 7

where are fatty acyl chains activated and why?

Answer 7

activated with CoA in cytoplasm to trap them in the cell

Question 8

how is the last round of beta oxidation different?

Answer 8

produces 2 acetyl CoAs and only 1 each of NADH and FADH2

Question 9

what is the signalling cascade that leads to TAG breakdown in fat cells?

Answer 9

epi and glucagon signalling → GTP bound a-G protein → adenylyl cyclase turns ATP → cAMP → activates PKA → phosphorylates triacylglycerol lipase (aka hormone sensitive lipase) → free fatty acids which can be transported in bloodstream with albumin

Question 10

albumin can be used to test for ___

Answer 10

hydrophobic molecules in the bloodstream

Question 11

where does the glycerol backbone go after fatty acids have been released?

Answer 11

gluconeogenesis to make glucose