TestUstad

Free Bioenergetics MCQs with Answers

1,378 Bioenergetics MCQs from Biology, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.

Cellular respiration explains how cells release energy from glucose through glycolysis, the link reaction, Krebs cycle and electron transport chain. It includes ATP production, substrate-level and oxidative phosphorylation, aerobic versus anaerobic respiration, and the roles of mitochondria, oxygen and fermentation in energy transfer.

Last updated

Cellular Respiration
Read the Bioenergetics notesFree MDCAT chapter notes with key terms

1,378 questions · page 23 of 69

441. Which wave lengths are mainly absorbed by chlorophyll?

  • A. Violet blue and red
  • B. Green and blue
  • C. Violet and orange
  • D. Red and indigo

Explanation: Chlorophyll primarily absorbs light in the blue and red regions of the electromagnetic spectrum.

Read the full explanation →
Correct answer: Violet blue and red

442. Which statement about chlorophyll is not true?

  • A. It contains terminal carbonyl group
  • B. It contains phyto tail
  • C. It contains porphyrin ring
  • D. It contains magnesium

Explanation: Chlorophyll is a complex molecule involved in photosynthesis, and it does contain a terminal carbonyl group.

Read the full explanation →
Correct answer: It contains terminal carbonyl group

443. Oleic acid is a fatty acid with 18 carbon atoms. It breaks down into 9 acetyl groups. It is estimated that these nine acetyl groups would generate _ ATP molecules.

  • A. 81
  • B. 98
  • C. 101
  • D. 108

Explanation: The breakdown of oleic acid into acetyl-CoA units involves beta-oxidation, where each acetyl-CoA enters the citric acid cycle.

Read the full explanation →
Correct answer: 108

444. Approximately how much calories of free energy is stored in plant biomass for every mole of CO2 fixed during photosynthesis ?

  • A. 110
  • B. 112
  • C. 114
  • D. 116

Explanation: The conversion of carbon dioxide (CO2) and water (H2O) into glucose (C6H12O6) involves the capture of light energy and its conversion into…

Read the full explanation →
Correct answer: 114

445. PGAL is formed during the oxidative phase of _.

  • A. Calvin Cycle
  • B. Glycolysis
  • C. Oxidative Phosphorylation
  • D. None of the above options are correct.

Explanation: PGA formed in the Carbon fixation of calvin cycle is reduced into phosphoglyceraldehyde. The products of light reaction i.e.

Read the full explanation →
Correct answer: Calvin Cycle

446. Van Neil's hypothesis about the production of oxygen during photosynthesis was based on the study and investigations of:

  • A. Bacteria
  • B. Algae
  • C. Protonema
  • D. Cyanobacteria

Explanation: Van Niel's hypothesis was formulated from his work with photosynthetic bacteria that utilized hydrogen sulfide (H₂S) instead of water…

Read the full explanation →
Correct answer: Bacteria

447. Location of photosynthetic pigments in purple sulfur bacteria:

  • A. Thylakoids
  • B. Grana
  • C. Stroma
  • D. Cytoplasm

Explanation: Purple sulfur bacteria are prokaryotic organisms that perform photosynthesis without chloroplasts.

Read the full explanation →
Correct answer: Cytoplasm

448. The quantitative study of energy relationship in a biological system is called?

  • A. Bioenergetics
  • B. Biochemistry
  • C. Biotechnology
  • D. Biophysics

Explanation: The quantitative study of energy relationships in a biological system is called bioenergetics.

Read the full explanation →
Correct answer: Bioenergetics

449. Which of the following chemical activity is involved in the conversion of pyruvate into acetaldehyde during anaerobic respiration?

  • A. Reduction
  • B. Decarboxylation
  • C. Oxidation
  • D. Phosphorylation

Explanation: During anaerobic respiration, specifically in a process called alcoholic fermentation, decarboxylation is involved in the conversion of…

Read the full explanation →
Correct answer: Decarboxylation

450. In glycolysis, the conversion of Glucose-6-phosphate to fructose-6-phosphate involves:

  • A. Phosphorylation
  • B. Oxidation
  • C. Isomerization
  • D. Reduction

Explanation: Isomerization is the formation of an isomer of a molecule such as glucose 6-phosphate is converted to fructose 6-phosphate via…

Read the full explanation →
Correct answer: Isomerization

451. Which of the following releases 7.3 kcal energy when terminal phosphate is lost?

  • A. NADP
  • B. ADP
  • C. ATP
  • D. FAD

Explanation: ATP has three phosphate groups. Energy is stored in the bonds joining the phosphate groups.

Read the full explanation →
Correct answer: ATP

452. To reduce one molecule of O2 _ _ _ electron(s) must be passed through the electron transport chain and _ _ _ molecule(s) of NADH ls(are) oxidized.

  • A. 1:1
  • B. 4:4
  • C. 1:2
  • D. 4:2

Explanation: For every 2 electrons carried by respiratory electron chain, one molecule of NADH is oxidized. This gives a ratio of 2:1.

Read the full explanation →
Correct answer: 4:2

453. "Photo-phosph-rylation" is:

  • A. ATP synthesis by food energy
  • B. ATP synthesis by solar energy
  • C. ATP synthesis by source of water
  • D. ATP synthesis by source of NADH2

Explanation: It is the process of utilizing light energy to convert ADP to ATP.

Read the full explanation →
Correct answer: ATP synthesis by solar energy

454. Which type of mammalian cell does not carry out oxidative phosphorylation?

  • A. Cardiac muscle cells
  • B. Liver cells
  • C. Neurons
  • D. RBCs

Explanation: RBCs have a biconcave shape and it lacks nucleus and mitochondria and hence many metabolic pathways such as oxidative phosphorylation.

Read the full explanation →
Correct answer: RBCs

455. A drug reduces mitochondrial activity in nephrons of the kidney. Which chemical will be present in increased amounts in the urine?

  • A. Ammonia
  • B. Glucose
  • C. Hydrogen bicarbonate
  • D. Urea

Explanation: This happens because in mitochondria aerobic respiration occurs(breakdown of food in presence of oxygen)The food is glucose.Aerobic…

Read the full explanation →
Correct answer: Glucose

456. During which of the following processes ATP is produced? (I) Photosynthesis(II) Aerobic respiration(III) Anaerobic respiration

  • A. I only
  • B. II only
  • C. I and II only
  • D. I, II and III only

Explanation: ATP is produced during photosynthesis as well as aerobic and anaerobic respiration.

Read the full explanation →
Correct answer: I, II and III only

457. Green plants carry on respiration

  • A. Only during the day
  • B. Only at night
  • C. During both day and night
  • D. Only when photosynthesis is going on

Explanation: Respiration is the process by which cells generate energy from glucose and oxygen, and it is a continuous metabolic activity necessary for…

Read the full explanation →
Correct answer: During both day and night

458. Photophosphorylation during photosynthesis results in the formation of:

  • A. ATP
  • B. NAD
  • C. FAD
  • D. ADP

Explanation: Photophosphorylation is the process of utilizing light energy from photosynthesis to convert ADP to ATP.

Read the full explanation →
Correct answer: ATP

459. A process of CO₂ fixation in photosynthesis by which the first product is the four-carbon oxaloacetate molecule is called:

  • A. C3 photosynthesis
  • B. C4 photosynthesis
  • C. Light reaction
  • D. Cyclic electron flow

Explanation: The correct answer is C4 photosynthesis. In C4 photosynthesis, carbon dioxide is initially fixed into a four-carbon compound…

Read the full explanation →
Correct answer: C4 photosynthesis

460. The first stable product of the Calvin cycle is

  • A. 3-phosphoglycerate
  • B. 1,3-biphosphoglycerate
  • C. Glyceraldehyde-3-phosphate
  • D. Ribulose-5-phosphate

Explanation: The correct option is 3-phosphoglycerate, as it is the first stable product formed during the Calvin cycle after carbon fixation.

Read the full explanation →
Correct answer: 3-phosphoglycerate
Start Free Bioenergetics Practice MCQs Test