Biocehemistry- Muscle Metabolism

Question 1

give 5 qualities of type I fibers

Answer 1

fatigue resistant, high myoglobin, high oxidative capacity, low glycogen content and glycolytic capacity

Question 2

where does most of cardiac ME come from

Answer 2

fatty acids

Question 3

how come ATP levels do not fall when muscle is elctronically twitched

Answer 3

because of the replishment of ATP via CK

Question 4

what muscle enzyme operates to maintain ATP levels and prevent the accumulation of ADP.

Answer 4

Adenylate cyclase

Question 5

ATP levels fall very little until ____

Answer 5

fatigue is approached

Question 6

In fast twitch muscle fibers ATP and phosphocreatine stores only sustain vigourous cotnraction for ____ and then _____ must be utilized to replenish ATP

Answer 6

a few seconds, metabolism

Question 7

Initial ATP production is achieved by switching on

Answer 7

glycolysis

Question 8

In type IIA and IIB fibers, the glucose substrate for glycolysis may come from _____ ______, especially in vigorous contraction.

Answer 8

muscle glycogen

Question 9

In times of stress, ________ will activate glycogen breakdown even more potently.

Answer 9

epinephrine

Question 10

______, ______, and ________ all activate phosphofructokinase 1 (PFK 1), the controlling enzyme of glycolysis.

Answer 10

AMP, Pi and NH3

Question 11

____level is probably primarily responsible for activation of PFK-1 (and consequently glycolysis) on the initial contraction of muscle. Also activates glycogen phosphorylase b

Answer 11

AMP

Question 12

is a glycogen storage disease (Type V) resulting from a genetic deficiency of muscle glycogen phosphorylase. It results in unusual fatigue and painful muscle cramps on exercise.

Answer 12

McArdle’s Disease

Question 13

___ activates isocitrate dehydrogenase

Answer 13

ADP

Question 14

Overall in muscle, at rest,______is the major source of ATP except after a high carbohydrate meal.

Answer 14

lipid

Question 15

During intense exercise, ______ is the major source (over short periods, glycogen in fiber types IIa and IIb).

Answer 15

carbohydrate

Question 16

one major disadvantage of carbohydrate usage is that it

Answer 16

produces about 7 times less energy per gram

Question 17

how do we overcome the carbohydrate problem

Answer 17

having small stores of glycogen for use in extreme conditions requiring high power output.

Question 18

continued heavy breathing after cessation of vigorous exercise in order to convert lactate back to pyruvate and NADH re-oxidized

Answer 18

Oxygen Debt

Question 19

Lactate can diffuse out of muscle and be transported to the liver, where it can be converted to glucose by gluconeogenesis. Known as _____ ____

Answer 19

Cori Cycle

Question 20

Is muscle fatigue directly due to the accumulation of lactate ( what is the most significant contributor)

Answer 20

NO……fuck NO (Phosphate, decreased pH)

Question 21

what is a mjaor controlling enzyme in glycolosysi

Answer 21

PFK1

Question 22

Increased _______levels in the brain could lead to increased levels of serotonin, which promotes relaxation and sleep

Answer 22

tryptophan

Question 23

The controlling enzyme of glycogen synthesis is ____________ (glucosyl transferase) Insulin, released in response to intake of glucose, activates this enzyme.
(G-6-P also stimulates its non-active form).

Answer 23

glycogen synthetase

Question 24

At rest, types I and IIA fibers produce their ATP from ____and _____, mostly _____ except after a high carbohydrate meal.

Answer 24

lipid, glucose, lipid

Question 25

Muscles containing a higher proportion of red fibers have higher____ activity.

Answer 25

LPL

Question 26

lipolysis is switched on by _____ and ______

Answer 26

epinephrine and glucagon

Question 27

FABP is present in cells with a greater ____ capacity, such as ______

Answer 27

oxidative, cardiac cells

Question 28

endurance training enhances the ability of type __ and ___ fibers to oxidize fatty acids

Answer 28

I, IIA

Question 29

At rest, types I and IIA muscle fibers preferentially use _________ as fuel.

Answer 29

fatty acids

Question 30

fatty acids are metabolized to _____ which inhibits pyruvate dehydrogenase

Answer 30

acetyl coa

Question 31

acetyl coa is then coverted to ___ which inhibits PFK

Answer 31

citrate

Question 32

how does glucose take over as the source of energy after a high carbohydrate meal

Answer 32

secretes insulin which inhibits lipolysis,

Question 33

early stages of fasting the major source of energy is_____ _____.
This reserves all available glucose for the brain

Answer 33

fatty acids

Question 34

In starvation, the degradation of muscle proteins provides the carbon skeletons of amino acids for gluconeogenesis by the liver

Answer 34

yea, they do

Question 35

Quantitatively muscle releases far more alanine and glutamine

Answer 35

yep