Question

1. How may c-subunits are believed to be present in the c-ring of mammalian mitochondria? A. 8 B. 10 C. 12 D. 15 E. 15

2. Which enzyme(s) (or enzymatic steps) is(are) likely to be regulatory?

A. those with mass action ratios much less than Keq,

B. the first enzyme in metabolic pathway,

C. the first enzyme unique to a branch in a pathway,

D. those with disequilibrium ratios much less than 1

E. all of the above

F. none of the above.

3. SERBP, SCAP, Insig and Sec are proteins associated with regulating the synthesis of HMG-CoA reductase and other enzymes of cholesterol synthesis and uptake. What compounds bind to SCAP and Insig to down-regulate HMG-CoA reductase and cholesterol synthesis?

A. ammonia and urea

B. glutamate and glutamine

C. sterols and oxysterols

D. IMP and OMP

E. all of the above

F. none of the above,

4. Scatchard analysis may give information about?

A. the ligand binding constant (Kb) of a protein,

B. the number of ligand binding sites on a protein,

C. the type of homotropic cooperativity with ligand binding,

D. Bmax

E. all of the above,

F. none of the above.

5. The pentose phosphate pathway?

A. Is important in the synthesis of NADPH.

B. Metabolizes glucose 6-phosphate and thus may compete with the glycolysis pathway.

C. Is located in the cell cytosol.

D. Is the main pathway for the synthesis of ribose 5-phosphate.

E. All of the above.

F. None of the above.

Answer 1

Answer-1: correct answer is option-A

Explanation: these c-subunits are found in the ATPase machinery of mitochondria and for mammals, its number is fixed to 8.

Answer-2: correct answer is option- D

Explanation: The disequilibrium ratio is defined as the ratio of mass action to equilibrium constant. So, when the value of disequilibrium ratio is lesser than 1 then the free energy value will be negative. Negative value of free energy makes the enzymatic reaction feasible.

Answer-3: correct answer is option- C

Explaination: Accumulation of sterols and oxysterols stops the machinery of HMG-COA reductase for the further synthetis of sterols.