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

Which of the following assumptions is/are made to make calculations of the net gain of ATP for every glucose molecule oxidised?

  1. Only glucose is being respired

  2. No other intermediate in the pathway is utilised to synthesise any other compound.

  3. The NADH synthesised in glycolysis is transferred into the mitochondria.

  4. A sequential orderly pathway is functioning.

  5. All of the above
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

This is the correct option as all of the above are assumptions to make calculations of the net gain of ATP for every glucose molecule oxidised.

Multiple choice

Which of the following statements is/are false?

a. In anaerobic organisms, glycosis is the only process in respiration. b. Glucose undergoes partial oxidation in glycosis to form two molecules of pyruvic acid. c. Sucrose is converted into glucose and fructose by the enzyme hexokinase.

  1. Only a

  2. Only a and b

  3. Only b

  4. Only b and c

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

This is the correct option as this statement is false. Sucrose is converted into glucose and fructose by the enzyme invertase.

Multiple choice

Which of the following statements is/are false?

a. In eukaryotes, aerobic respiration takes place within the cytoplasm. b. In many prokaryotes, fermentation takes place under anaerobic conditions. c. The metabolic pathway through which the electron passes from one carrier to another is called the electron transport system.

  1. Only a

  2. Only a and b

  3. Only b

  4. Only b and c

  5. Only c
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

This is the correct option as this statement is false. In eukaryotes, aerobic respiration takes place within the mitochondria.

Multiple choice

Which of the following is not a characteristic property of aerobic respiration?

  1. In aerobic respiration, there is a complete oxidation of pyruvate.

  2. In aerobic respiration, two molecules of NADH are produced from the metabolism of two molecules of pyruvic acid.

  3. NADH is oxidised to NAD+ very slowly in aerobic respiration.

  4. Glucose is completely degraded to CO2 and H2O in aerobic respiration.

  5. In aerobic respiration, many molecules of ATP are generated.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

This is the correct option as this is not a characteristic property of aerobic respiration.

Multiple choice

Which of the following is NOT correctly matched?

  1. Oxidoreductases: Catalyze oxidation/reduction reactions

  2. Lyases: Catalyze the hydrolysis of various bonds

  3. Isomerases: Catalyze isomerization changes within a single molecule

  4. Ligases: Join two molecules with covalent bonds
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Lyases is a class of enzymes, which cleave various bonds by means other than hydrolysis and oxidation. Hydrolases is a class of enzymes, which catalyze the hydrolysis of various bonds.

Multiple choice

In sodium-potassium pump, the event of dephosphorylation occurs when

  1. 3 Na+ ions bind to the active site of the pump

  2. 2 molecules of K+ bind to the pump at their respective binding sites

  3. hydrolysis of ATP takes place after Na+ ions bind to ATP

  4. K+ ions are transported into the cell
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

When the pump binds two molecules of K+ to their respective bonding sites on the extracellular face of the transport protein, dephosphorylation of the pump occurs.