fat as fuel

Question 1

energy yield of fat, protein, carb

Answer 1

fat: 38kj
protein: 21kj
carbs: 7kj

Question 2

how are TAGs broken down? which hormones promote this? what are the fates of these products

Answer 2

TAG broken down by lipases into free FA and glycerol
promoted by adrenaline and glucagon
FA bound to albumin
glycerol diffuses in bloodstream-> enters glycolysis in tissues-> pyruvate OR glucose (liver and in starvation)

Question 3

where and how are long chain FA activated

Answer 3

in cytoplasm;
by CoA, ATP-> AMP + PPi
into FATTY ACYL COA

Question 4

transport of FA into mitochondria

Answer 4

fatty acyl coA moves across outer mitochondrial membrane. coA exchanged for carnitine by CARNITINE PALMITOYL-TRANSFERASE 1 -> fatty acyl-carnitine
translocase transports fatty acyl-carnitine across inner mitochondrial membrane
carnitine exchanged for coA by CARNITINE PALMITOYL TRANSFERASE 2 -> fatty-acyl coA

Question 5

step 1 in beta oxidation

Answer 5

fatty acyl coA-> enoyl coA
by ACYL COA DEHYDROGENASE
FADH2 produced

Question 6

step 2 in beta oxidation

Answer 6

enoyl coA-> 3-L-hydroxyacyl-CoA
by ENOYL COA HYDRATASE
USES H2O

Question 7

step 3 in beta oxidation

Answer 7

3-L-hydroxyacyl-coA-> beta-ketoacyl-coA
by 3-L-HYDROXYACYLCOA-DEHYDROGENASE
produces NADH

Question 8

step 4 in beta oxidation

Answer 8

beta-ketoacyl-coA-> fatty acyl coA (2C shorter) + acetyl CoA
by BETA-KETOACYL-COA THIOLASE
Uses coA

Question 9

what happens to the products of beta oxidation

Answer 9

acetyl coA -> TCA

fatty acyl coA (2c shorter)-> enters beta oxidation again

Question 10

how many acetyl coAs will a 16-C FA produce; how many ATPs will be produced

Answer 10

8 acetyl coAs.
8 acetyl coAs go through TCA 8 times. 1 round of TCA produces 10 ATP. total 10x8=80
16-C FA goes through beta oxidation 7 times
7 NADH and 7 FADH2 produced
ATP from beta oxidation= 7x2.5 + 7x1.5 =28
total atp= 80 +28 -2=106
(-2 from conversion of FA-> fatty acyl coA)

Question 11

what happens to FA with odd number of C atoms

Answer 11

results in 3C CoA;
converted into succinyl coA (4C) -> TCA
uses B12

Question 12

what kind of energy does brain, muscle, adipose

Answer 12

brain: glucose + ketone ( in starvation)
muscle: glucose + FA + ketone (in starvation)
adipose: TAG