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

The electron flow from complex I to complex III occurs via

  1. cytochrome c

  2. ubiquinone

  3. complex II

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

Ubiquinone is bound to the inner mitochondrial membrane of mitochondria . It is the only enzyme that participates in both the citric acid cycle and the electron transport chain. The electron flow from complex I to complex III occurs via ubiquinone.

Multiple choice

Which of the following statements is/are false?

a. Uric acid increases in muscle cells when they are lacking in oxygen. b. The breathing and respiration in woody stem of a plant takes place through the lenticels. c. Pyruvate can be converted into ethanol and carbon dioxide by yeast.

  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. Lactic acid increases in muscle cells when they are lacking in oxygen.

Multiple choice

Choose the incorrect reaction.

  1. Ribulose-1,5-bisphosphate → 3-phosphoglycerate: Rubisco

  2. 3-Phosphoglycerate → Glycerate-1,3-bisphosphate: Phosphoglycerate kinase

  3. Dihydroxy acetone phosphate → Fructose 1,6-bisphosphate: Aldolase

  4. Xylulose 5-phosphate → Ribulose 5-phosphate: ribose-5-phosphate isomerase

  5. Ribulose 5-phosphate → Ribulose-1,5-bisphosphate: Phosphoribulokinase ribose 5-phosphate isomerise
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Conversion of xylulose 5-phosphate to ribulose 5-phosphate is catalysed by ribulose-phosphate epimerase. Conversion of ribose 5-phosphate to ribulose 5-phosphate is catalysed by ribose 5-phosphate isomerise.

Multiple choice

Which of the following was not used by Stanley L .Miller and Harold C. Urey while creating a primitive environment in the laboratory?

  1. Water

  2. Methane

  3. Ammonia

  4. Oxygen

  5. Hydrogen
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Yes, it is the correct answer. Stanley L. Miller and Harold C. Urey conducted the Miller-Urey experiment in 1953 to demonstrate how  life would have originated on the earth. They created an environment in laboratory, which mimicked the environment of earth as it was during the time of origin of life. Water, methane, ammonia and hydrogen were used in that experiment.

Multiple choice

What does the term feedback refer to?

  1. Effect of substrate on the rate of enzymatic reaction.

  2. Effect of end product on the rate of reaction.

  3. Effect of enzyme concentration on the rate of reaction.

  4. Effect of external compound on the rate of reaction.

  5. Effect of cytoplasm on the rate of reaction.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The effect of end product on the rate of reaction is referred as feedback mechanism.

Multiple choice

What does the turn over number of an enzyme mean?

  1. Number of substrate molecules acted upon by one molecule of an enzyme per minute.

  2. Number of enzyme molecules acting on one molecule of substrate per minute.

  3. Number of molecules of end product produced by an enzyme in one minute.

  4. Number of substrate molecules acted upon by an enzyme per second.

  5. Number of enzyme molecules participating in the chemical reaction.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Number of substrate molecules acted upon by one molecule of an enzyme per minute is called the turn over number of an enzyme.

Multiple choice

One molecule of an enzyme is needed to convert 2 molecules of a substrate into products in 5 minutes. 10 molecules of the enzyme and 25 molecules of the substrate are mixed in a test tube. After 10 minutes, the test tube will be having ____________.

  1. products only

  2. products and 5 molecules of unreacted substrate

  3. products, enzymes and 5 molecules of unreacted substrate

  4. unreacted substrates

  5. products and enzymes
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

Products and enzymes will be left in the test tube. As the substrate will be completely converted into products and the enzymes can be recovered as such at the end of the reaction.