Question

1.

What statements about muscle cells and ATP are TRUE? There may be more than one answer. Select one or more:

a. Muscle cells involved in aerobic metabolism have longer endurance and have greater force generating capacity than muscles involved in anaerobic metabolism.

b. Muscle cells involved in aerobic metabolism have longer endurance but have smaller muscle mass than muscles involved in anaerobic metabolism.

c. When muscle cell is at work, creatine kinase will convert ADP + creatine into ATP + creatine phosphate.

d. When muscle cell is at rest, creatine kinase converts ATP + creatine into ADP + creatine phosphate. e. Muscle cells involved in aerobic metabolism have a lower threshold for muscle fatigue compare to muscles involved in anaerobic metabolism.

2.

Which of the following statements about glucose metabolism is TRUE? Can be more than one answer

Select one or more:

a. Glycolysis occurs in the cytosol with or without oxygen present inside the cell.

b. At the end of glycolysis, 1 molecule of glucose is converted into 2 pyruvate + 2 ATP + 2 NADH.

c. The net products of anaerobic metabolism are 2 pyruvate + 2NADH   + 2ATP.

d. One molecule of glucose is first converted into glucose-6 phosphate by hexokinase.

e. In the intermediate steps between glycolysis and Kreb cycle, 2 pyruvate + 2 Coenzyme A molecules in the mitochondrial matrix will give rise to 2 Acetyl CoA + 2 CO₂ + 2 NADH.

3. What are the correct statements about glucose transporters (GLUT)?

Select one or more:

a. GLUT-2 is found at the liver cells and beta cells of the pancreas.

b. GLUT-4 is found at the working muscle cells and adipose tissues.

c. GLUT transporters move glucose via simple and facilitated diffusion.

d. When insulin binds at the tyrosine kinase receptor of the resting muscle cells, the reaction will promote GLUT-2 insertion at the cell membrane

e. When the resting muscle cells are active during exercise, muscle cells become independent of insulin.

Answer 1

1. Option a and Option d stands as TRUE.

Muscle cells involved in aerobic metabolism changes composition of muscle fibres thereby increasing endurance and it lasts long. They also have greater force generating capacity due to increased myoglobin and mitochondria in muscle tissue when compared to anaerobic metabolism.

Muscle cells involved in aerobic metabolism promotes recovery and repair of muscles thereby consisting muscle growth and have larger muscle mass.

When muscle cell is at work it needs ATP for energy. So that creatine kinase will convert ADP + creatine phosphate into ATP + creatine. When muscle cell is at rest creatine kinase converts ATP + creatine into ADP + creatine phosphate, thus storing the energy in the form of creatine phosphate in the muscles.

Muscle cells involved in aerobic metabolism fatigue lately when compared to muscles involved in anaerobic metabolism where fatigue sets in in early stage due to accumulation of lactate generated from pyruvate.

2.Option a,b,d,e stands as TRUE.

Glycolysis occurs in the cytosol with or without oxygen present inside the cell as it doesn't require any oxygen. At the end of glycolysis one molecule of glucose is converted into two molecules of pyruvate and two molecules of ATP because 2 ATP are utilised and 4 ATP produced. So, show the net gain is 2 ATP and 2 NADH.

The net products of anaerobic metabolism are 2 lactate + 2 NADH + 2 ATP. One molecule of glucose is first converted into glucose-6-phosphate by utilising ATP under the action of hexokinase enzyme. This is the first step of glycolysis. In the intermediate step which occurs between glycolysis and krebs cycle, 2 pyruvate + 2 coenzyme A molecules in the mitochondrial matrix will give rise to 2 acetyl coA + 2 CO₂ + 2 NADH.

3.Option a,b,e stands CORRECT.

GLUT-2 are found at liver cells and Beta cells of pancreas in which they secrete insulin. GLUT-4 are found at working muscle cells like skeletal muscles and cardiac muscles and adipose tissues.

GLUT transporters move glucose via facilitated diffusion. When insulin binds at tyrosine kinase receptor of resting muscle cells the reaction will promote GLUT-4 insertion at cell membrane.

When the resting muscle cells are active during exercise aur during muscle contraction the GLUT-4 translocate independent of insulin.