Respiration in Plants MCQs

Consider the following statements regarding Pyruvate transport and Link Reaction:

I. Pyruvate is transported from cytosol into mitochondrial matrix.
II. Pyruvate undergoes oxidative decarboxylation catalysed by pyruvate dehydrogenase.
III. The link reaction requires coenzymes including NAD⁺ and Coenzyme A (CoA).
IV. One molecule of CO₂ and one NADH + H⁺ are produced per pyruvate molecule.

Which of the statements given above are correct?

Read the following statements about Citric Acid Cycle condensation:

I. TCA cycle begins with condensation of acetyl group with Oxaloacetic Acid (OAA) and water.
II. The condensation reaction is catalyzed by citrate synthase.
III. A molecule of Coenzyme A (CoA) is liberated during citrate formation.
IV. Citric acid formed is a 4-carbon dicarboxylic acid.

Which statements are correct?

Consider the decarboxylation steps in TCA cycle:

I. Citric acid (6C) isomerizes to Isocitrate (6C).
II. Isocitrate undergoes first decarboxylation to form α-ketoglutaric acid (5C).
III. α-Ketoglutaric acid (5C) undergoes second decarboxylation to form Succinyl-CoA (4C).
IV. Succinyl-CoA (4C) undergoes third decarboxylation to form Succinic acid (4C).

Which of the above statements are correct?

Regarding substrate-level phosphorylation in Krebs Cycle:

I. Succinyl-CoA is converted to Succinic acid.
II. A molecule of GTP is synthesized directly.
III. GTP is converted to GDP with simultaneous synthesis of ATP from ADP in a coupled reaction.
IV. This step requires molecular oxygen.

Which statements are correct?

Total reduced coenzymes generated per turn of TCA cycle (from ONE Acetyl-CoA):

I. Three molecules of NADH + H⁺.
II. One molecule of FADH₂.
III. Two molecules of FADH₂.
IV. One molecule of GTP / ATP.

Which option gives the correct numbers?

Statement analysis on regeneration of Oxaloacetic Acid (OAA):

I. Continued oxidation of Acetyl-CoA requires continuous replenishment of OAA.
II. OAA is the first member and acceptor molecule of the TCA cycle.
III. OAA is a 4-carbon compound (4C).
IV. Conversion of Malic acid to OAA generates a molecule of FADH₂.

Which statements are correct?

Summary equation of TCA cycle per molecule of Pyruvic Acid includes:

I. 3 NAD⁺ + 1 FAD + ADP + P_i + Pyruvate + 2H₂O → 3CO₂ + 4NADH + 4H⁺ + FADH₂ + ATP (including link reaction).
II. Four NAD⁺ are reduced to four NADH + 4H⁺ (1 in link reaction + 3 in TCA).
III. One FAD is reduced to one FADH₂.
IV. Six CO₂ molecules are evolved per pyruvate.

Which statements are correct?

Consider the following statements regarding Hans Krebs:

I. Hans Krebs elucidated the Tricarboxylic Acid Cycle (Krebs cycle).
II. TCA cycle operates in the cytoplasm of eukaryotic cells.
III. The cycle is named TCA cycle because the first stable product has three carboxyl groups.
IV. TCA cycle operates only under aerobic conditions in mitochondria.

Which statements are correct?

Sequential order of intermediates in Krebs Cycle:

I. Citric acid (6C) → α-Ketoglutaric acid (5C).
II. α-Ketoglutaric acid (5C) → Succinic acid (4C).
III. Succinic acid (4C) → Malic acid (4C).
IV. Malic acid (4C) → Oxaloacetic acid (4C).

Which option shows the correct sequential order?

Regarding coenzymes and ions required for Pyruvate Dehydrogenase:

I. Requires NAD⁺ as electron acceptor.
II. Requires Coenzyme A (CoA).
III. Requires Mg²⁺ ions.
IV. Requires Ca²⁺ ions as an essential structural atom of pyruvate.

Which statements are correct?