Question

Iron-sulphur proteins contain:

a. amino acids, haem and ribose

b. iron, ribose and sulphur but no haem

c. iron, amino acids and sulphur plus haem

d. iron, amino acids and sulphur but no haem

Which reaction occurs in the citric acid cycle?

a. Lactate is reduced to form NAD+

b. Fumarate is hydrolysed to form malate

c. Glyceraldhyde-3P is oxidised to form NADH + H+

d. Fumarate is hydrolysed to form H2O and NADH + H+

What is the function of mitochondrial ATP synthase?

a. It produces ATP using the electrochemical potential of mitochondria.

b. It produces ATP using phosphoenolpyruvate and ADP as substrates

c. It produces ATP using the electrochemical potential of the plasma membrane.

d. It reduces lactate to pyruvate using ADP as a substrate.

During photosynthesis the light harvesting reactions takes place:

a. in mitochondria using the mitochondrial ATP synthase and light.

b. in chloroplasts using photosystem I, mitochondrial ATP synthase plus light for its reactions.

c. in chloroplast using photosystem I alone but not photosystem II.

d. in two steps using two different photosystems, photosystem I and II.

Answer 1

1. Iron-sulphur proteins contain

Answer: c: iron, amino acids, sulphur plus haem.

Amino acids are the building blocks of proteins. Heme is the iron containing part and many amino acids contain sulphur.

2. Which reaction occurs in a Citric Acid Cycle?

Answer : b. Fumarate is hydrolysed to form malate.

In step number 7 of Citric acid cycle or Kreb's cycle, Fumarate changes to a 4 carbon malate in the presence of water and enzyme fumarase.

3. What is the function of mitochondrial ATP synthetase?

Answer: a: It produces ATP using the electro-chemical potential of mitochondria.

ATP synthetase synthesises ATP from ADP and inorganic phosphate or Pi. This is possible due to the energy which is derived from the gradient or slope of protons which move from intermembranous space into the matrix.

4. During photosynthesis the light harvesting reactions takes place :

Answer-d: In two steps using two different photosystems, photosystem I and II.

The thylakoid membranes of chloroplasts have 2 kinds of photosystems, each with it's set of light harvesting chlorophyll and carotenoid molecules.A photon absorbed anywhere in the harvesting zone can pass its energy. P680 forms photosystem II and P700 forms photosystem I.