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 bio-chemistry organization of life concept of metabolism metabolism in animals metabolism

Glycogenolysis is a 

  1. Anabolic reaction

  2. Catabolic reaction

  3. Both A and B

  4. None of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The catabolic processes are the reactions in which the large complex molecules are broken down to produce smaller organic molecules. The polysaccharide which is a complex molecule is broken down to from many small monosaccharide molecules. For example, glycogen is broken down to produce glucose molecules and the process is known as glycogenolysis. 

Thus, the correct answer is option B. 

Multiple choice bio-chemistry organization of life concept of metabolism metabolism in animals metabolism

Formation of nucleotide is a

  1. Anabolic reaction

  2. Catabolic reaction

  3. Both A and B

  4. None of the above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The nucleotides can be formed by two paths. When the nucleotide is formed due to the breaking of the bonds in the RNA and DNA, this process is an example of a catabolic process. When the nucleotides are formed from the nucleosides and nitrogenous bases, then this is an example of an anabolic process. 

Thus, the correct answer is option C. 

Multiple choice bio-chemistry organization of life concept of metabolism metabolism in animals metabolism

Which of the following statement can be related to catabolism?

  1. It is an exergonic reaction

  2. It is an endergonic reaction

  3. It helps to break complex molecules to simple ones.

  4. Both A and C
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The catabolic processes are the reactions in which the large complex molecules are broken down to form the smaller molecules. The process is an exergonic process in which the energy is released due to the breaking of the bonds of the larger complex molecules. The energy is released due to breaking of the bonds in the ATP molecule to produce ADP or AMP. 

Thus, the correct answer is option D. 

Multiple choice bio-chemistry organization of life concept of metabolism metabolism in animals metabolism

Which is correct for catabolism of 18 C fatty acid

  1. Mitochondria, beta oxidation, 148 ATP molecules

  2. Mitochondria, beta oxidation, 140 ATP molecules

  3. Cytosol, beta oxidation, 146 ATP molecules

  4. Cytosol, beta oxidation, 140 ATP molecules
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

For an 18-carbon fatty acid (stearic acid), beta-oxidation occurs in the mitochondria. The process yields 9 acetyl-CoA, 8 NADH, and 8 FADH2, resulting in a total of 148 ATP molecules after complete oxidation.

Multiple choice bio-chemistry organization of life concept of metabolism metabolism in animals metabolism

Identify the anabolic process from the following.

  1. Photosynthesis

  2. Glycolysis

  3. Hydrolysis of starch

  4. Respiration
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
  • Anabolism is the category of metabolism in which bio-molecules are synthesized. Whereas catabolism is breaking down of bio-molecules into simpler forms, mostly for the release of energy. 
  • During photosynthesis, carbohydrate is formed from carbon dioxide and water in presence of sunlight. 
  • Glycolysis is catabolic process releasing ATP.
  • Hydrolysis of starch is the break down of starch into simpler monosaccharides using water.
  • Respiration is the oxidative process releasing ATP. It has both catabolic as well as anabolic reactions involved hence it is rather considered as an amphibolic process.
So, the correct option is 'Photosynthesis'.
Multiple choice bio-chemistry organization of life concept of metabolism metabolism in animals metabolism

Which of the following is a catabolic reaction?

  1. Intercellular digestion

  2. Intracellular digestion

  3. Respiration

  4. All of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The catabolic processes are the reactions in which the large complex molecules are broken down to form the smaller molecules. The process is an exergonic process in which the energy is released due to the breaking of the bonds of the larger complex molecules. Intracellular digestion refers to the breaking of the larger molecules. Intercellular digestion is the processes in which the molecules are broken down outside the cell and then absorbed. During internal respiration, there is the breakdown of the molecules to produce ATP. 

Thus, the correct answer is option D. 

Multiple choice bio-chemistry organization of life concept of metabolism metabolism in animals metabolism

Choose the correct answers from the alternatives given .
All the chemical energy transformations that occur within a cell is called

  1. metabolism

  2. adaptation

  3. homeostasis

  4. photosynthesis
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
Metabolism is the set of life-sustaining chemical processes that enable organisms to transform the chemical energy stored in molecules into energy that can be used for cellular processes.
So, the correct option is 'metabolism'
Multiple choice bio-chemistry organization of life concept of metabolism metabolism in animals metabolism

State whether the following statements are true or false .
A metabolic pathway is a sequence of chemical reactions in which each step is controlled by its own specific enzymes.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Enzymes are organic catalysts which aid in facilitating chemical reactions in the body. Each metabolic pathway consists of a series of biochemical reactions that are connected by their intermediates: the products of one reaction are the substrates for subsequent reactions, and so on. Any metabolic pathway inside our body (for example glycolysis) requires several enzymes working in a sequential manner. 

So, the correct option is 'True'.

Multiple choice bio-chemistry organization of life concept of metabolism metabolism in animals metabolism

Choose the correct answers from the alternatives given .
All the biochemical pathways in a cell constitute

  1. Coupling reactions

  2. Endergonic reactions only

  3. Exergonic reactions only

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

There are various biochemical reactions taking inside a cell. Some of these reactions may result in absorption of energy (called as endergonic reactions) or release of energy (called as exergonic reactions). Often both these types of reactions are coupled, to get the energy to those endergonic reactions, they are paired up with energy-releasing exergonic reactions (known as coupling reactions). Although, there are a wide variety of reactions taking place inside the body apart from these reactions. Metabolism is a term that is used to describe all these biochemical reactions involved in maintaining the living state of the cells and the organism. 

So, the correct option is 'Metabolism'.


Multiple choice evs deficiency diseases need for nutrients nutrients needed by the body balanced diet and malnutrition food for health nutrition and its deficiency nutrition and its need

Reduced coenzyme NADPH $(H^+)$ is produced in respiration during

  1. Glycolysis

  2. PPP

  3. Krebs cycle

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

PPP or pentose phosphate pathway is an important pathway that takes place in the cytoplasm.

 It is an alternative path for the Krebs cycle and is the only pathway that forms reduced NADH. The enzyme transhydrogenase, that transfers the hydrogen of NADPH to NAD and forms NADH.
So, the correct option is 'PPP'

Multiple choice biology life processes in living organisms- part 1 amphibolic pathway living organisms and energy production respiration in plants

Which of the following forms the connecting link between glycolysis and Kreb's cycle?

  1. Glucose

  2. Ethyl alcohol

  3. Lactic acid

  4. Pyruvic acid
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
Pyruvic acid is produced as a final end product of glycolysis. This pyruvic acid then forms acetyl CoA. This acetyl CoA, acts as initial compound of Kreb's cycle.
So, the correct answer is 'Pyruvic acid'
Multiple choice biology respiration in plants amphibolic pathway living organisms and energy production life processes in living organisms- part 1

Out of 38 molecules of ATP produced after aerobic respiration of glucose, the break up in ATP production in glycolysis (P). pyruvic acid to acetyl CoA formation (Q) and Krebs cycle (R) is 

  1. P = 2, Q = 6, R = 30

  2. P = 8, Q = 6, R = 24

  3. P = 8, Q = 10, R = 20

  4. P = 2, Q = 12, R = 24
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Glycolysis produces 8 ATP (2 net ATP + 2 NADH yielding 6 ATP via shuttle), link reaction produces 6 ATP (2 NADH), and the Krebs cycle produces 24 ATP (6 NADH, 2 FADH2, 2 GTP/ATP). The total is 38 ATP.

Multiple choice biology respiration in plants amphibolic pathway living organisms and energy production life processes in living organisms- part 1

Which of the two statements together support that respiratory pathway is an amphibolic pathway.
i) Fats breakdown to glycerol and fatty acids, subsequently yields acetyl CoA
ii) In respiration C-C bonds of complex compounds breakdown through oxidation leading to release of energy
iii) Acetyl CoA from respiratory pathway is withdrawn for synthesis of fatty acids
iv) Proteins are degraded by protease to amino acids and enter the respiratory pathway

  1. i, ii

  2. i, iv

  3. ii, iv

  4. ii, iii
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Statement ii describes the catabolic nature (breakdown of C-C bonds), while statement iii describes the anabolic nature (withdrawal of intermediates like Acetyl CoA for fatty acid synthesis), together defining the amphibolic pathway.

Multiple choice biology respiration in plants amphibolic pathway living organisms and energy production life processes in living organisms- part 1

Largest amount of phosphate bound energy is produced in the process of respiration during 

  1. Anaerobic respiration

  2. Glycolysis

  3. Krebs cycle

  4. None of the above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

During the process of glycolysis 8 ATP molecules are produced in aerobic respiration. In the case of Krebs cycle 30 ATP molecules can be produced.

Multiple choice biology respiration in plants amphibolic pathway living organisms and energy production life processes in living organisms- part 1

The process by which the energy of glucose is released under aerobic respiration was discovered by

  1. Hopkins

  2. Lister

  3. Krebs

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

The process by which the energy of glucose is released under aerobic respiration, was discovered by Hans Krebs. The Krebs cycle is a part of cellular respiration. It is a series of chemical reactions used by all aerobic organisms to generate energy.