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MCQ on Krebs Cycle

In this Article we are going to look at Mcqs on Krebs Cycle and many more.

The Krebs cycle is a sequence of chemical reactions that use oxygen as part of cellular respiration and are essential in all living cells. The Krebs cycle is the second of four steps that occur during the process of cellular respiration. It’s a crucial stage in the oxidative phosphorylation process.

The Krebs cycle, also known as the tricarboxylic acid cycle (TCA cycle) or citric acid cycle, is a sequence of chemical reactions that use oxygen as part of cellular respiration in all living cells. In eukaryotes, the Krebs cycle occurs in the mitochondria, but in prokaryotes, it occurs in the protoplasm.

Question

Q.1. In 1953, Krebs was given the Nobel Prize for elucidating

  1. ATP metabolism

  2. Energy Forming Process in the Cell

  3. Oxidation of Cytoplasm

  4. Respiration chain

Answer: The Correct Answer is Energy Forming Process in the Cell. Hans Adolf Krebs “for his discovery of the citric acid cycle” and Fritz Albert Lipmann “for his discovery of coenzyme A and its importance for intermediate metabolism” shared the Nobel Prize in Physiology or Medicine in 1953.

Q.2. What is the Product formed by maleic Dehydrogenase?

  1. Oxaloacetic Acid

  2. Succinic Acid

  3. Fumaric Acid

  4. Maleic Acid

Answer: The Correct Answer is Oxaloacetic Acid. The enzymatic activity of malic dehydrogenase on malate results in the production of oxaloacetic acid. This is a stage in the TCA cycle. NADH is generated as a by-product of this process.

Q.3. Pyruvic acid is converted to……….. In the presence of TPP and carboxylase.

  1. Ethyl Alcohol and CO2

  2. Citric Acid and CO2

  3. Acetaldehyde and CO2

  4. None OF the Above

Answer: The Correct Answer is Acetaldehyde and CO2. In the presence of TPP and carboxylase, pyruvic acid is transformed to acetaldehyde and CO2 during alcoholic fermentation. Acetaldehyde is oxidised further to produce ethanol.

Q.4. Which Coenzyme is used in acetylation reaction

  1. CoA

  2. FMN

  3. FAD

  4. None of These

Answer: The Correct Answer is CoA. Lysine acetyltransferases (KATs), which use acetyl coenzyme A (CoA) as a substrate, catalyse the acetylation of histones and proteins. Acetyl-CoA is a critical metabolite found at the intersections of key catabolic and anabolic pathways, and its concentration in the cell reflects the cell’s metabolic status.

Q.5. Basically krebs’ Cycle is termed as the aerobic Phase of Respiration Because

  1. Aerobic Conditions are essential for the continued operation of the Electron Transport System.

  2. It Consumes Oxygen.

  3. Oxygen acts as a Catalyst

  4. None of the Above

Answer: The Correct Answer is Aerobic Conditions are essential for the continued operation of Electron Transport System. In the mitochondrial matrix, the Kreb cycle produces 8 molecules of NADH and 2 molecules of FADH2 (through succinate dehydrogenase). NADH and FADH2 pump electrons through a sequence of electron transport proteins to the final acceptor oxygen during electron transport across the inner mitochondrial membrane.

This electron transport chain ensures that NAD and FAD are available for the next Kreb cycle round. When these reducing powers aren’t available, pyruvate enters the anaerobic respiration route. As a result, oxidation of NADH and FADH2 by oxygen is required to sustain the Kreb cycle’s continuity, and the cycle is classified as aerobic. 

Q.6. Mention the part that is not involved in Krebs cycle

  1. Acetylation

  2. Dehydrogenation

  3. Oxidative Phosphorylation

  4. Decarboxylation

Answer: The Correct Answer is Oxidative Phosphorylation. krebs’ cycle does not include oxidative phosphorylation. The krebs’ cycle, commonly known as the Tricarboxylic acid cycle, is a mechanism in which acetate is oxidised for energy in aerobic organisms. Acetyl CoA is generated by the oxidative decarboxylation of pyruvic acid in Krebs cycle.

Q.7. What is the Other name of Krebs Cycle

  1. EMP pathway

  2. Citric acid cycle

  3. Glyoxylate Cycle

  4. Glycolate Cycle

Answer: The Correct option is Citric acid cycle. The Krebs cycle is a process that occurs in the One of the most significant reaction sequences in biochemistry is the Krebs cycle, commonly known as the citric acid cycle or the tricarboxylic acid cycle.

Q.8. What is Pyruvic Acid in Respiration?

  1. A result of Protein Breakdown

  2. Broken down into two carbon fragments and CO2

  3. One of the Product of Krebs Cycle 

  4. Formed only when Oxygen is Available

Answer: The Correct Answer is Broken down into two carbon fragments and CO2. Pyruvic acid is broken down into carbon fragments and CO2 during respiration. In aerobic respiration, pyruvic acid is slowly broken down in a complicated chain of events known as the Krebs cycle. A total of 34 ATP molecules are created during this cycle.

Q.9. Kreb’s cycle begins with the creation of six carbon compounds as a result of a reaction between two carbon compounds namely

  1. Succinic Acid and pyruvic acid

  2. Acetyl CoA and Oxaloacetic Acid

  3. Fumaric acid and Pyruvic acid

  4. Maleic acid and acetyl CoA

Answer: The Correct answer is Acetyl CoA and Oxaloacetic Acid. The Krebs cycle begins with the interaction of oxaloacetic acid and acetyl CoA, which produces a six-carbon molecule. Citric acid is generated as a result of this process, which is mediated by citrate synthase.

Q.10. During Electron Transport which of the following oxidative phosphorylation occurs

  1. Mitochondria

  2. Ribosomes

  3. Glyoxysomes

  4. Chloroplast

Answer: The Correct answer is Mitochondria. Oxidative phosphorylation is a process that involves both the oxidation of substrates and the generation of ATP in the mitochondria of all animal and plant tissues. The two carrier molecules NAD or FAD transfer hydrogen ions (or electrons) to the electron transport pumps as the krebs’ cycle operates.

Q.11.In the Process of respiration, largest amount of Phosphate bond energy is produced during

  1. Kreb’s Cycle

  2. Anaerobic Respiration

  3. Glycolysis

  4. None of the Above 

Answer: The Correct Answer is Kreb’s Cycle. Two moles of ATP are created during glycolysis. Glycolysis is the process of converting glucose into two molecules of pyruvate, which is catalysed by enzymes. A single cycle produces 12 ATP. In aerobic respiration in mitochondria, the Krebs cycle is a frequent metabolic process or oxidative catabolism.

It is involved in protein, carbohydrate, and lipid catabolism. Only two ATPs are generated during anaerobic respiration (respiration without oxygen). Fermentation is the non-molecular oxygen-dependent generation of chemical energy in the form of ATP from the breakdown of carbohydrates and other organic compounds.