Krebs Cycle

Q.

A competitive inhibitor of succinic dehydrogenase is?

1. α-ketoglutarate

2. Oxaloacetate

3. Malonate

4. Malate

Q.

What are the irreversible steps of the TCA cycle?

Q. When one molecule of glucose is completely oxidised during aerobic respiration, how many molecules of carbon dioxide are released due to tricarboxylic acid cycle?

1. One
2. Two
3. Three
4. Four

Q.

In mitochondria, chemiosmosis translocates protons from the matrix into the intermembrane space, whereas in chloroplasts, chemiosmosis translocates protons from

1. the stroma to the photosystem II.

2. the matrix to the stroma.

3. the stroma to the thylakoid space.

4. the intermembrane space to the matrix.

Q. Which one is product of aerobic respiration?

1. Malic acid
2. Ethyl alcohol
3. Lactic acid
4. Pyruvic acid

Q.

What Is TCA Cycle in Biochemistry?

Q.

Is pyruvic acid the end product of glycolysis?

Q. EMP can produce a total of _______ ATPs.

1. 6
2. 8
3. 24
4. 38

Q.

Is oxidative decarboxylation reversible?

Q.

Give theschematic representation of an overall view of Krebs cycle.

Q. Krebs cycle begins with ________.

1. Condensation of acetyl-CoA with OAA and $H_{2}O$ to yield citric acid
2. Conversion of OAA into citric acid through oxidation of $NA{D}^{+}$
3. Oxidative decarboxylation of pyruvic acid to acetyl CoA
4. Cleavage of succinyl CoA into succinic acid and coenzyme A.

Q. How many molecules of carbon dioxide are released in Krebs cycle per glucose molecule?

1. 2
2. 3
3. 4
4. 6

Q. The organism in which Kreb's cycle does not occur in mitochondria is

1. yeast
2. E.coli
3. Ulothrix
4. plants

Q.

Does pyruvate enter the mitochondria?

Q.

Select the option which is not correct with respect to enzyme action.

1. Malonate is a competitive inhibitor of succinate dehydrogenase.

2. The addition of a lot of succinates does not reverse the inhibition of succinate dehydrogenase by malonate.

3. A non competitive inhibitor binds the enzyme at a site distinct from that which binds the substrate.

4. The substrate binds with enzymes at its active site.

Q. Four respiratory enzymes are given below. Arrange them in the increasing order of carbon numbers of their substrates.
I. Enolase, II. Aconitase, III. Fumarase, IV. Alcohol dehydrogenase

1. II, IV, III, I
2. IV, I, II, III
3. I, IV, III, II
4. IV, I, III, II

Q. Final decarboxylation in Krebs cycle occur between

1. citric acid and 𝝰-ketoglutaric acid
2. 𝝰-ketoglutaric acid and succinic acid
3. succinic acid and malic acid
4. malic acid and oxalo acetic acid

Q. The complete oxidation of one pyruvate by the stepwise removal of hydrogen atoms produces:

1. Two molecules of $FAD{H}_2$
2. Three molecules of $C{O}_2$
3. Two molecules of $GTP$
4. Two molecules of $NADP{H}_2$

Q. Krebs cycle occurs in

1. mitochondria
2. chloroplast
3. cytoplasm
4. ribosomes

Q. FAD is electron acceptor during oxidation of which of the following?

1. α-ketoglucarate -> Succinyl Co-A
2. Succinic acid -> Fumaric acid
3. Succinyl Co-A -> Succinic acid
4. Fumaric acid -> Malic acid

Q. The 5C organic acid intermediate of Krebs cycle that is a key compound in the nitrogen metabolism of the cell is __.

Q. Respiratory enzymes are activated by

1. N and P
2. Mg and Mn
3. K and Ca
4. S and Fe

Q. Arrange the compounds in the order they are formed during Kreb's cycle.

1. Fumarate
2. Malate
3. Succinyl-CoA
4. Citrate
5. Succinate

Q. In the TCA cycle, isomerisation of citrate is followed by how many decarboxylation(s) to form succinic acid?

1. 2
2. 3
3. 1
4. 4

Q. Which one of the following statements regarding enzyme inhibition is correct?

1. Non-competitive inhibitors often bind to the enzyme irreversibly.
2. Competitive inhibition is seen when a substrate competes with an enzyme for binding to an inhibitor protein.
3. Competitive inhibition is seen when the substrate and the inhibitor compete for the active site on the enzyme.
4. Non-competitive inhibition of an enzyme can be overcome by adding a large amount of substrate.

Q. How many NADH + $H^{+}$ are formed in per turn of Krebs cycle

1. 2
2. 3
3. 4
4. 5

Q. All enzymes of the tricarboxylic acid cycle are located in the mitochondrial matrix except one. In prokaryotes, this enzyme is present in the cytoplasm. Identify the enzyme and its location in eukaryotes.

1. Lactate dehydrogenase in outer mitochondrial membrane
2. Isocitrate dehydrogenase in inner mitochondrial membrane
3. Malate dehydrogenase in the thylakoid membrane
4. Succinate dehydrogenase in inner mitochondrial membrane

Q. Acceptor of acetyl CoA in Krebs cycle is

1. malic acid
2. fumaric acid
3. 𝝰- ketoglutaric acid
4. oxaloacetic acid

Q. What would be expected to happen if:
(a) GA${}_3$ is applied to rice seedlings.
(b) Dividing cells stop differentiating.
(c) A rotten fruit gets mixed with unripe fruits.
(d) You forget to add cytokinin to the culture medium.

Q. In which one of the following options, the two names refer to one and the same thing?

1. Citric acid cycle and Calvin cycle
2. Tricarboxylic acid cycle and Urea cycle
3. Krebs cycle and Calvin cycle
4. Tricarboxylic acid cycle and Citric acid cycle