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

How does gluconeogenesis contribute to the Cori cycle?

  1. By converting lactate to glucose in the liver

  2. By converting glucose to lactate in skeletal muscle

  3. By transporting lactate from skeletal muscle to the liver

  4. By transporting glucose from the liver to skeletal muscle

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

Gluconeogenesis contributes to the Cori cycle by converting lactate to glucose in the liver, converting glucose to lactate in skeletal muscle, transporting lactate from skeletal muscle to the liver, and transporting glucose from the liver to skeletal muscle.

Multiple choice

How does gluconeogenesis contribute to the overall energy metabolism of the body?

  1. It provides a source of glucose for energy production

  2. It helps maintain blood glucose levels during fasting or starvation

  3. It helps spare glycogen stores

  4. It helps prevent ketosis

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

Gluconeogenesis contributes to the overall energy metabolism of the body by providing a source of glucose for energy production, helping maintain blood glucose levels during fasting or starvation, helping spare glycogen stores, and helping prevent ketosis.

Multiple choice

What are some potential therapeutic applications of targeting gluconeogenesis?

  1. Treatment of type 1 diabetes

  2. Treatment of type 2 diabetes

  3. Treatment of obesity

  4. Treatment of non-alcoholic fatty liver disease

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

Targeting gluconeogenesis has potential therapeutic applications in the treatment of type 1 diabetes, type 2 diabetes, obesity, and non-alcoholic fatty liver disease.

Multiple choice

Which enzyme is responsible for the breakdown of purine nucleotides?

  1. Nucleoside phosphorylase

  2. Nucleoside hydrolase

  3. Purine nucleoside phosphorylase

  4. Adenine deaminase
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Purine nucleoside phosphorylase is the enzyme that catalyzes the breakdown of purine nucleotides into nucleosides and phosphate.

Multiple choice

Which enzyme catalyzes the synthesis of purine nucleotides de novo?

  1. Phosphoribosyl pyrophosphate amidotransferase

  2. Inosine monophosphate dehydrogenase

  3. Adenosine monophosphate deaminase

  4. Guanine monophosphate synthase
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Phosphoribosyl pyrophosphate amidotransferase is the enzyme that catalyzes the first step in the de novo synthesis of purine nucleotides.

Multiple choice

Which enzyme catalyzes the conversion of orotic acid to uridine monophosphate (UMP)?

  1. Orotidine 5'-phosphate decarboxylase

  2. Uridine kinase

  3. Uridine phosphorylase

  4. Uridine diphosphate kinase
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Orotidine 5'-phosphate decarboxylase is the enzyme that catalyzes the conversion of orotic acid to UMP.

Multiple choice

What is the role of salvage pathways in nucleotide metabolism?

  1. To synthesize nucleotides de novo

  2. To recycle nucleotides that have been degraded

  3. To convert purine nucleotides to pyrimidine nucleotides

  4. To convert deoxyribonucleotides to ribonucleotides
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Salvage pathways are responsible for recycling nucleotides that have been degraded.

Multiple choice

Which enzyme catalyzes the conversion of adenosine to inosine?

  1. Adenosine deaminase

  2. Adenosine kinase

  3. Adenosine phosphorylase

  4. Adenosine diphosphate kinase
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Adenosine deaminase is the enzyme that catalyzes the conversion of adenosine to inosine.

Multiple choice

Which enzyme catalyzes the conversion of deoxythymidine monophosphate (dTMP) to deoxythymidine (dT)?

  1. Thymidine kinase

  2. Thymidine phosphorylase

  3. Thymidine diphosphate kinase

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

Thymidine phosphorylase is the enzyme that catalyzes the conversion of dTMP to dT.

Multiple choice

What is the role of dihydrofolate reductase (DHFR) in nucleotide metabolism?

  1. To reduce dihydrofolate to tetrahydrofolate

  2. To convert folate to dihydrofolate

  3. To synthesize purine nucleotides

  4. To synthesize pyrimidine nucleotides
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

DHFR is responsible for reducing dihydrofolate to tetrahydrofolate.

Multiple choice

Which enzyme catalyzes the conversion of guanine to xanthine?

  1. Guanine deaminase

  2. Guanine kinase

  3. Guanine phosphorylase

  4. Guanine diphosphate kinase
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Guanine deaminase is the enzyme that catalyzes the conversion of guanine to xanthine.

Multiple choice

What is the role of nicotinamide adenine dinucleotide (NAD+) in nucleotide metabolism?

  1. As an electron acceptor in redox reactions

  2. As a precursor for the synthesis of NADH

  3. As a cofactor in the synthesis of purine nucleotides

  4. As a cofactor in the synthesis of pyrimidine nucleotides
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

NAD+ is an electron acceptor in redox reactions.

Multiple choice

Which enzyme catalyzes the conversion of cytidine to uridine?

  1. Cytidine deaminase

  2. Cytidine kinase

  3. Cytidine phosphorylase

  4. Cytidine diphosphate kinase
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Cytidine deaminase is the enzyme that catalyzes the conversion of cytidine to uridine.

Multiple choice

Which of the following is the process by which cells die due to oxidative stress?

  1. Pyroptosis

  2. Ferroptosis

  3. Necroptosis

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

Ferroptosis is the process by which cells die due to oxidative stress.

Multiple choice

Which cellular process is responsible for breaking down glucose to produce energy in the form of ATP?

  1. Glycolysis

  2. Krebs Cycle

  3. Electron Transport Chain

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

Glycolysis is the first stage of cellular respiration, where glucose is broken down into pyruvate, generating a small amount of ATP and NADH.