Regulation of metabolic pathway is done by following ways except one, mark the one?
A.
Substrate concentration
B.
Allosteric regulation of enzymes
C.
Availability of oxygen
D.
Extracellular signals i.e. hormones or growth factors
Answer: Option C
Explanation:
Metabolic pathways depend on the substrate concentration as well as extracellular signals. Coenzymes or certain metabolic intermediate also regulate the metabolism while not all the metabolic pathways depend on the oxygen. Oxygen is required only for aerobic reactions.
Which of the following is not an enzyme-catalyzed reaction in metabolism?
A.
Isomerization and elimination
B.
Internal rearrangement
C.
Maillard reaction
D.
Free radical reaction
Answer: Option C
Explanation:
Metabolic reactions fall into five categories: group transfer, making or breaking carbon bonds, internal rearrangement, free radical reactions, and isomerizations while the Maillard reaction is a non-enzymatic reaction in which amino group-containing compounds react with sugar molecules.
Name the inhibition where end products of biosynthesis pathway inhibit the activity of the first enzyme?
A.
Feedback inhibition
B.
Feedback repression
C.
Allosteric inhibition
D.
Competitive inhibition
Answer: Option A
Explanation:
Feedback inhibition is also known as end-product inhibition, the unique feature in this is the inhibition of the first enzyme in a biosynthetic pathway by the end product which in turn control its production.
In which of the following phenomenon the end product act as co-repressor and repress the synthesis of metabolic enzymes?
A.
Allosteric regulation
B.
Feedback repression
C.
Feedback inhibition
D.
Regulation by phosphorylation
Answer: Option B
Explanation:
Feedback repression is different from feedback inhibition, here the end product of the pathway acts as a co-repressor and represses the synthesis of an enzyme which is required at the earlier stage of the pathway.
