MBBS Biochemistry 2

Question 1

Gaucher disease results from deficiency of which enzyme?

Accepted Answer

Glucocerebrosidase (beta-glucosidase)

Answer

Gaucher disease is the most common lysosomal storage disorder, caused by glucocerebrosidase deficiency, leading to glucocerebroside accumulation in macrophages.

Question 2

Which of the following is the primary product of the pentose phosphate pathway?

Accepted Answer

NADPH and ribose-5-phosphate

Answer

The pentose phosphate pathway generates NADPH (for reductive biosynthesis and antioxidant defense) and ribose-5-phosphate (for nucleotide synthesis).

Question 3

The DNA double helix is held together by which type of bonds between base pairs?

Accepted Answer

Hydrogen bonds

Answer

Complementary base pairs (A-T and G-C) in DNA are held together by hydrogen bonds; G-C pairs have 3 hydrogen bonds and A-T pairs have 2.

Question 4

Which lipoprotein is responsible for transporting cholesterol from peripheral tissues to the liver (reverse cholesterol transport)?

Accepted Answer

HDL

Answer

HDL mediates reverse cholesterol transport, collecting cholesterol from peripheral tissues and transporting it to the liver for excretion.

Question 5

Vitamin B12 deficiency causes megaloblastic anemia through impaired synthesis of which molecule?

Accepted Answer

Thymidine (dTMP)

Answer

B12 deficiency impairs methionine synthesis, trapping folate as methyl-THF and preventing thymidine synthesis, impairing DNA replication and causing megaloblastic anemia.

MBBS - Bachelor of Medicine and Bachelor of Surgery Practice Test

MBBS - Bachelor of Medicine and Bachelor of Surgery Practice Test

MBBS Biochemistry 2