Energy Metabolism

Question 1

Major fuel sources for skeletal muscle

Answer 1

Glucose and fatty acids

Question 2

Primary energy source during fasting in skeletal muscles

Answer 2

Fatty acids

Question 3

Describe fast-twitch muscles

Answer 3

Larger muscles, low high ATPase, white, low myoglobin, short term high intensity exercises, easily fatigues

Question 4

Describe slow-twitch muscles

Answer 4

Smaller muscles, low ATPase, red, high myoglobin, prolonged, moderate exercise, not easily fatigued

Question 5

Where is hexokinase found?

Answer 5

Widely distributed in tissues

Question 6

Where is Glucokinase found?

Answer 6

Only in hepatocytes and pancreatic cells.

Question 7

rate limiting enzyme in glycolysis

Answer 7

Phosphofructokinase I that converts fructose-6-phosphate to frutose- 1,6-bisphosphate

Question 8

How is phosphofructokinase I activated?

Answer 8

Insulin activates PFK2 which makes F2,6P which activates PFK1

Question 9

How is phosphofructokinase inhibited?

Answer 9

Glucagon inhibits PFK2 which lowers F2,6P which inhibits PFK1

Question 10

Produced through the reaction of glyceraldehyde 3-phosphate dehydrogenase

Answer 10

Conversion of NAD to NADH

Question 11

Produced through the reaction of 3 phosphoglycerate kinase

Answer 11

Conversion of ADP to ATP

Question 12

Produced through the reaction of pyruvate kinase

Answer 12

Conversion of ADP to ATP

Question 13

Activator of pyruvate kinase

Answer 13

Fructose 1,6 bisphosphate from PFK1 reaction

Question 14

How does lactate dehydrogenase continue glycolysis?

Answer 14

LDH converts NADH to NAD, releasing the coenzyme needed for glyceraldehyde-3-phosphate dehydrogenase

Question 15

2 Electron Shuttles

Answer 15

Malate shuttle - NADH

Glycerol phosphate shuttle- FADH2

Question 16

Pyruvate dehydrogenase and alpha ketoglutarate dehydrogenase complexes are made up of which enzymes?

Answer 16

pyruvate dehydrogenase/decarboxylase , Dihydrolipoyl transacetylase and Dihydrolipoyl dehydrogenase

Question 17

What amino acids are incorporated into the TCA and where?

Answer 17

Alanine- pyruvate

Aspartate- oxaloacetate

phenylalanin/tyrosine- fumarate

Valine, Methionine, Isoleucine & threonin - succinyl CoA

Glutamine - alpha ketoglutarate

Question 18

Inhibitors of PFK1

Answer 18

ATP and citrate

Question 19

Activators of PFK1

Answer 19

AMP, Fructose 2,6 Bisphosphate

Question 20

Activators of carbamoyl phosphate synthetase II

Answer 20

ATP and PRPP

Question 21

Which enzyme is inhibited by glucose 6 phosphate?

Answer 21

Hexokinase

Question 22

Which enzyme is inhibited by fructose 6 phosphate?

Answer 22

Glucokinase

Question 23

Activator of pyruvate kinase

Answer 23

Fructose-1,6-bisphosphate