Biology

Cellular Respiration and Enzymes

1,551 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

Assertion (A): During aerobic respiration, lesser number of ATPs is produced in eukaryotes than in prokaryotes. Reason (R): In eukaryotes, some energy is lost when electrons are shuttled across the mitochondrial membranes that separate glycolysis (in cytoplasm) from the electron transport chain.

Directions: In the following question, there are two statements, Assertion (A) and Reason (R). Consider both the statements independently and mark your answers as under:

1. A and R both are correct and R is the correct explanation of A.
2. A and R both are correct and R is not the correct explanation of A.
3. A is correct and R is incorrect.
4. A is incorrect and R is correct.
5. A and R both are incorrect.

  1. A and R both are correct and R is the correct explanation of A.

  2. A and R both are correct and R is not the correct explanation of A.

  3. A is correct and R is incorrect.

  4. A is incorrect and R is correct.

  5. A and R both are incorrect.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

During aerobic respiration, lesser number of ATPs is produced in eukaryotes (34 molecules of ATP) than in prokaryotes (38 molecules of ATP). This is because of the reason that, In eukaryotes some energy is lost when electrons are shuttled across the mitochondrial membranes that separate glycolysis (in cytoplasm) from the electron transport chain. No such separate mechanism exists in prokaryotes.

Multiple choice

Which of the following statements is/are true regarding Entner–Doudoroff pathway?

  1. It is an alternate series of reactions that catabolise glucose to pyruvate.
  2. Occurs both in prokaryotes as well as eukaryotes.
  3. Has a net yield of 2 ATP for every glucose molecule metabolised.

  1. Only 1

  2. Only 2

  3. Only 3

  4. 1 and 2

  5. 2 and 3
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Entner–Doudoroff pathway is an alternate series of reactions that catabolise glucose to pyruvate using a set of enzymes different from those used in glycolysis or pentose phosphate pathway.

Multiple choice

Glyconeogenesis is the process of ___________.

  1. formation of glycogen from glucose

  2. breakdown of glycogen into glucose

  3. formation of glucose from fatty acids, fats or proteins

  4. formation of glycogen from fatty acids, fats or proteins

  5. formation of pyruvic acid from glucose
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The process of formation of glycogen from fatty acids, fats or proteins is called glyconeogenesis.

Multiple choice

Which of the following statements is/are correct?

a. Respiration breaks food by oxidising it and releasing energy. b. Energy produced during respiration is stored in ADP molecules. c. ADP cells have a high energy content.

  1. a, b and c

  2. a and b

  3. a and c

  4. b and c

  5. a only
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

This is the correct answer. Respiration includes breathing and oxidation of food in the cells. It breaks food by oxidising it and releasing energy.

Multiple choice

Acetyl Co A is produced from pyruvate by:

  1. oxidative hydrogenation

  2. oxidative phosphorespiration

  3. oxidative decarboxylation

  4. oxidative photophosphorylation

  5. oxidative phosphorylation
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Oxidative decarboxylation results in the conversion of pyruvate into Acetyl Co A.

Multiple choice

Citric acid cycle is the alternative name of:

  1. Calvin cycle

  2. HMP shunt

  3. ETS

  4. Glycolysis

  5. TCA cycle
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

Tricaboxylic acid cycle is also called citric acid cycle, which results in the complete oxidation of pyruvate into CO2 and H2O.

Multiple choice

Which of the following enzymes acts on peroxide as an acceptor?

  1. Superoxide dismutase

  2. Cytochrome c oxidase

  3. Nitrate reductase

  4. Catalase

  5. Glutathione reductase
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Catalase belongs to Category EC 1.11 of oxidoreductases (EC 1), which act on peroxide as an acceptor. Catalase catalyses the decomposition of hydrogen peroxide to water and oxygen.

Multiple choice

Which of the following enzymes acts on the aldehyde or oxo group of donors?

  1. Pyruvate dehydrogenase

  2. Alcohol dehydrogenase

  3. NADH dehydrogenase

  4. Malate dehydrogenase

  5. Glycerol dehydrogenase
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Pyruvate dehydrogenase belongs to Category EC 1.2 of oxidoreductases (EC 1), which act on the aldehyde or oxo group of donors. Pyruvate dehydrogenase performs the first two reactions within the pyruvate dehydrogenase complex: decarboxylation of pyruvate and reductive acetylation of lipoic acid.