Metabolism 3

Question 1

transport of acyl-coA into mitochondrial matrix: what cycle?

Answer 1

acyl coA + carnitine via CAT1 = acyl carnitine. translocase swaps acyl carnitine for a carnitine (antiport). CAT II converts acyl carnitine into carnitine.

Question 2

what determines rate of transport of acyl coA into mito. matrix?

Answer 2

indirectly determined by CAT 1 - and thus CAT 1 determines rate of Box

Question 3

Boxidation: definition?

Answer 3

cyclical process via which fatty acids are broken down, two carbon atoms at a time to produce acetyl coA (plus lots of ATP)

Question 4

oxidation of fatty acids occurs under ___ conditions only

Answer 4

aerobic

Question 5

what happens to acetyl coA in muscle

Answer 5

catabolized via CAC and OXP PHOS to make lots of ATP

Question 6

what happens to acetyl coA in liver

Answer 6

converted to a special type of fuel molecule for export in blood stream: ketone bodies

Question 7

acetyl co A cannot be used to make?

Answer 7

glucose

Question 8

ketone bodies: definition and properties

Answer 8

metabolic fuel molecules: small, water soluble + easily transported in the blood (vs. FAs which are hard to transport)

Question 9

ketone bodies: made how?

Answer 9

two acetyl coA combined together

Question 10

some problems with ketone bodies

Answer 10

acidic = metabolic problems. acetone is also not good for you; side product of ketone body production when it happens a lot

Question 11

fatty acid synthesis: occurs mainly where? enables?

Answer 11

mainly in the liver. enables storage of excess acetyl coA (excess glucose; amino acids)

Question 12

first step of FAS?

Answer 12

acetyl coA must be transported OUT of the mitochondrial matrix (since that’s where it is always made)

Question 13

FAS: all carbon atoms come from? process involves?

Answer 13

acetyl coA: sequential addition of two carbon atoms from acetyl co A to the growing acyl chain

Question 14

FAS: rate limiting step?

Answer 14

formation of new carbon carbon bond which requires energy, catalyzed by acetyl co A carboxylase (ACC)

Question 15

FAS ends with the production of?

Answer 15

palmitate (16:0)

Question 16

regulation of triacyglycerols: breakdown and synthesis? (also include location)

Answer 16

lipolysis (adipose tissue) determined by activity of hormone sensitive lipase. fat synthesis (adipocytes and liver) only limited by supply.

Question 17

regulation of fatty acids: synthesis and breakdown? (also include location)

Answer 17

FAS (liver) determined by ACC activity. Box (liver and muscle) determined by regulating transport of FAs into mitochondrial matrix via CAT 1

Question 18

hormone sensitive lipase: effects of insulin and glucagon?

Answer 18

insulin (promotes storage/use) inhibits HSL. glucagon activates HSL (promotes breakdown)

Question 19

rate of B-ox is ____ but there are no? instead, tightly controlled by what 3 things?

Answer 19

highly variable but no rate limiting enzymes. tightly controlled by ADP local concentration, enzyme induction, inhibition of fatty acid transport

Question 20

ADP effect on Box

Answer 20

higher ADP = increases beta oxidation (less ATP = more ADP so you want more breakdown)

Question 21

inhibition of fatty acid transport and B-ox?

Answer 21

reciprocal regulation of B-ox and FAS. 1st intermediated of FAS, malonyl coA, inhibits CAT 1 so inhibits transport to where B-ox would take place)