Fatty oxidation, Amino acid degradation and energy metabolism


1. Name the three keto-acids which are common in both carbohydrate and protein catabolism.

Brain does not use amino acids as fuel sources but ammonia toxicity is observed in brain the most. Why?

2. Urea cycle enzymes are present in a. cytosol and mictochondria of brain cells b. cytosol and mictochondria of Muscle cells c. cytosol of liver cells d. cytosol and mictochondria of liver cells

3. What are the ultimate catabolic products of Amino acids in mammalians?

4. What are the carriers of amino gp (ammonia) in blood?

5. During heavy exercise muscles produce excess of pyruvate due to accelerated glycolysis and lower oxygen availability. This pyruvate is used up for gluconeo genesis. How does the puruvate transported to liver?

6. What is Cori cycle?

7. If CAC is blocked, will it affect the metabolic flux of Urea cycle?

8. What are the metabolites and enzymes that directly or indirectly regulate the urea cycle?

9. Which metabolic product of Urea cycle is a member of CAC?

10. Ammonia toxicity leads to depletion of ATP in brain. Explain How?

11. How many ATP molecules will be produced if Alanine or Serine or

Cysteine is completely catabolized? (Calculate 3ATP/NADH and


12. Which metabolic pathway is defective in Maple syrup urine disease? Name the enzyme and the amino acids involved.

13. Which cofactor or coenzyme acts as a one-carbon group carrier (e.g. methyl group) and which one as amino gp carrier?

14. Why are ketogenic amino acids especially important under condition of starvation or untreated diabetes?

15. Name the enzymes defective in phenyl ketonuria and alcaptonuria.

16. Why do diabetic patients feel so thirsty? Some time their breath has acetone smell. What is the reason ?

17. In amino acid catabolism, the first reaction for many amino acids is a(n): a.

decarboxylation requiring thiamine pyrophosphate (TPP). b.

hydroxylation requiring NADPH and O


. c.

oxidative deamination requiring NAD + . d.

reduction requiring pyridoxal phosphate (PLP). e.

transamination requiring pyridoxal phosphate (PLP).

18. The coenzyme involved in a transaminase reaction is:

A) biotin phosphate.

B) lipoic acid.

C) nicotinamide adenine dinucleotide phosphate (NADP + ).

D) pyridoxal phosphate (PLP).

E) thiamine pyrophosphate (TPP).

19. Transamination from alanine to

-ketoglutarate requires the coenzyme:

A) biotin.


C) No coenzyme is involved.

D) pyridoxal phosphate (PLP).

E) thiamine pyrophosphate (TPP).


Suppose you are responsible for formulating the diet for a 4-year-old boy with Maple

Syrup disease. How do you decide what kind and amount of protein to include in the diet?