Biology

Cellular Respiration and Enzymes

1,721 Questions

Explore key concepts of cellular respiration, including glycolysis, the Krebs cycle, and the electron transport chain. These questions also cover ATP production, anaerobic respiration, and essential metabolic pathways. This topic forms a core part of the biology syllabus for many competitive examinations.

Glycolysis and metabolic pathwaysKrebs cycle processesElectron transport chainATP production countAnaerobic respiration products

Cellular Respiration and Enzymes Questions

Multiple choice

Enzymes concerned with transfer of electrons are

  1. hydrolysases

  2. dehydrogenases

  3. transaminases

  4. proteases
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

A dehydrogenase (also called DH or DHase in the literature) is an enzyme belonging to the group of oxidoreductases that oxidizes a substrate by a reduction reaction that removes one or more hydrogens from a substrate to an electron acceptor, usually NAD+/NADP+ or a flavin coenzyme such as FAD or FMN.

Multiple choice

Which of the following enzymes is related with electron transfer?

  1. Hydrolase

  2. Dehydrogenase

  3. Desmolase

  4. Transminase
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

A dehydrogenase (also called DH or DHase in the literature) is an enzyme belonging to the group of oxidoreductases that oxidizes a substrate by a reduction reaction that removes one or more hydrogens from a substrate to an electron acceptor, usually NAD+/NADP+ or a flavin coenzyme such as FAD or FMN.

Multiple choice

Glycolysis is a part of

  1. anaerobic respiration

  2. aerobic respiration

  3. both aerobic and anaerobic respiration

  4. Krebs cycle
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Glycolysis is the first step in the breakdown of glucose. It occurs both in aerobic and anaerobic respiration.

Multiple choice

In human beings, the anaerobic respiration produces

  1. lactic acid

  2. glucose

  3. amino acid

  4. lactose
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Lactic acid is a compound produced when glucose is broken-down and oxidized. During intense exercise, when oxygen levels are lower, more lactic acid is produced.

Multiple choice

Net ATP formed during oxidation of glucose molecule in aerobic prokaryotes is

  1. 36 ATP

  2. 40 ATP

  3. 38 ATP

  4. 34 ATP
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

 In prokaryotic cell during glycolysis, 2 ATP is consumed and 4 ATP and 2 NADH is produced from each glucose, and each NADH produces 3 ATP, thus a total of 4 + 6 ATP = 10 ATP and net production of 10 - 2 ATP = 8 ATP  is produced, and 30 ATP in kerb cycle and pyruvic acid oxidation, thus net production of 30+8 =38 ATP occurs. 

Multiple choice

Which of the following is not true about glycolysis?

  1. It is the first stage of cellular respiration in plants.

  2. It requires oxygen for functioning.

  3. It occurs in the cytosol of cells.

  4. It produces 2 molecules each of ATP and NADH.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

 It may occur even in the absence of oxygen.

Multiple choice

Directions: The question consists of two statements: Assertion and Reason. While answering the question you are required to choose any of the following five responses. (A) If both Assertion and Reason are true and the Reason is a correct explanation of the Assertion; (B) If both Assertion and Reason are true, but Reason is not a correct explanation of the Assertion; (C) If Assertion is true, but the Reason is false; (D) If Assertion is false and Reason is true; (E) If both Assertion and Reason are false. Assertion: Glycolysis begins in the cytoplasm, resulting into two C-3 intermediates, then rearranges further to yield two molecules of pyruvate. Reason: During glycolysis, four ATP and two NADPH molecules are produced and the net yield is only two ATP molecules.

  1. (A)

  2. (B)

  3. (C)

  4. (D)
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Both the statements are true but reason is not the correct explanation of the assertion . Two molecules of pyruvate are formed and net gain of ATP is 8