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

What is the process by which carbohydrates are broken down into glucose?

  1. Glycolysis

  2. Gluconeogenesis

  3. Glycogenolysis

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

Glycolysis is the process by which carbohydrates are broken down into glucose.

Multiple choice

What is the process by which carbohydrates are converted into fats?

  1. Glycolysis

  2. Gluconeogenesis

  3. Glycogenolysis

  4. Lipogenesis
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Lipogenesis is the process by which carbohydrates are converted into fats.

Multiple choice

What are the main precursors for gluconeogenesis?

  1. Lactate

  2. Glycerol

  3. Alanine

  4. Glutamine

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

The main precursors for gluconeogenesis are lactate, glycerol, alanine, and glutamine, which are derived from the breakdown of proteins, fats, and lactate.

Multiple choice

What is the first step in gluconeogenesis?

  1. Conversion of pyruvate to oxaloacetate

  2. Conversion of oxaloacetate to phosphoenolpyruvate

  3. Conversion of phosphoenolpyruvate to fructose-1,6-bisphosphate

  4. Conversion of fructose-1,6-bisphosphate to glucose-6-phosphate
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The first step in gluconeogenesis is the conversion of pyruvate to oxaloacetate, which is catalyzed by the enzyme pyruvate carboxylase.

Multiple choice

What is the final step in gluconeogenesis?

  1. Conversion of pyruvate to oxaloacetate

  2. Conversion of oxaloacetate to phosphoenolpyruvate

  3. Conversion of phosphoenolpyruvate to fructose-1,6-bisphosphate

  4. Conversion of fructose-1,6-bisphosphate to glucose-6-phosphate
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The final step in gluconeogenesis is the conversion of fructose-1,6-bisphosphate to glucose-6-phosphate, which is catalyzed by the enzyme glucose-6-phosphatase.

Multiple choice

What is the net energy yield of gluconeogenesis?

  1. 6 ATP

  2. 8 ATP

  3. 10 ATP

  4. 12 ATP
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The net energy yield of gluconeogenesis is 6 ATP molecules per molecule of glucose produced.

Multiple choice

What is the physiological significance of gluconeogenesis?

  1. To maintain blood glucose levels during fasting or starvation

  2. To provide energy for muscle contraction

  3. To synthesize glycogen for storage

  4. To produce glucose for the brain

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

Gluconeogenesis has several physiological significances, including maintaining blood glucose levels during fasting or starvation, providing energy for muscle contraction, synthesizing glycogen for storage, and producing glucose for the brain.

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.