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.
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Read the Bioenergetics notesFree MDCAT chapter notes with key terms1,378 questions · page 38 of 69
- A. Four joined porphyrin rings
- B. Four joined tetrapyrrole rings
- C. Four joined pyrrole rings
- D. Two joined pyrrole rings
Explanation: The chlorophyll molecule has a head known as the porphyrin ring, which is made up of four pyrrole rings linked together.
Correct answer: Four joined pyrrole rings- A. Carbon of each porphyrin ring
- B. Hydrogen of each pyrrole ring
- C. Nitrogen of each porphyrin ring
- D. Oxygen atoms of the phytol tail
Explanation: The magnesium atom in the chlorophyll head is coordinated with the nitrogen atoms of the porphyrin ring.
Correct answer: Nitrogen of each porphyrin ring- A. α - chain
- B. β - chain
- C. Haem group
- D. Protein
Explanation: The correct answer is the heam group. Hemoglobin is composed of protein chains and a non-protein component, the haem group, which contains…
Correct answer: Haem group- A. Iron as central atom
- B. Magnesium as central atom
- C. Four pyrrole rings
- D. Central atom coordinated with nitrogen of each pyrrole ring
Explanation: The haem group of hemoglobin is characterized by having iron as its central metal atom.
Correct answer: Iron as central atom- A. Hydrocarbon tail
- B. Phytol
- C. Hydrophilic tail
- D. Carotenoid tail
Explanation: The correct answer is phytol. Phytol is the specific name for the long-chain alcohol that constitutes the hydrocarbon tail of chlorophyll…
Correct answer: Phytol- A. Thylakoid membrane by its head
- B. Lamellar membrane by its head
- C. Thylakoid membrane by its tail
- D. Lamellar membrane by its tail
Explanation: The chlorophyll molecule is embedded in the hydrophobic core of the thylakoid membrane by its hydrophobic tail.
Correct answer: Thylakoid membrane by its tail- A. Atoms
- B. Elements
- C. Functional groups
- D. Carbon atoms
Explanation: The primary difference between chlorophyll a and chlorophyll b is in their functional groups.
Correct answer: Functional groups- A. Carbon atoms
- B. Oxygen atoms
- C. Hydrogen atoms
- D. Hydrogen and oxygen atoms
Explanation: Chlorophyll a and chlorophyll b have the same basic structure, but they differ in the number of hydrogen and oxygen atoms.
Correct answer: Hydrogen and oxygen atoms- A. Two more hydrogen atoms
- B. One less oxygen atom
- C. Two less hydrogen atoms and one more oxygen atom
- D. Two more hydrogen atoms and one less oxygen atom
Explanation: Chlorophyll a and chlorophyll b differ primarily in one functional group attached to the porphyrin ring.
Correct answer: Two less hydrogen atoms and one more oxygen atom- A. Two more hydrogen atoms
- B. One less oxygen atom
- C. Two less hydrogen atoms
- D. Two more hydrogen atoms and one less oxygen atom
Explanation: Chlorophyll a differs from chlorophyll b in its chemical structure: it contains a methyl group (-CH₃) instead of a carbonyl group (-CHO).
Correct answer: Two more hydrogen atoms and one less oxygen atom- A. Carbonyl group with methyl group
- B. Magnesium with ferrous
- C. Methyl group with carbonyl group
- D. Ferrous with magnesium
Explanation: The primary structural difference between chlorophyll a and chlorophyll b is the presence of a methyl group (-CH3) in chlorophyll a, which…
Correct answer: Methyl group with carbonyl group- A. Carbonyl group with methyl group
- B. Magnesium with ferrous
- C. Ferrous with magnesium
- D. None of these
Explanation: Option A is correct. Chlorophyll b is converted into chlorophyll a by replacing the carbonyl group (formyl group) with a methyl group on…
Correct answer: Carbonyl group with methyl group- A. Absorbed, Absorbed
- B. Not absorbed, Weakly absorbed
- C. Not absorbed, Not absorbed
- D. Absorbed, Reflected
Explanation: Option D is correct. Chlorophyll a and chlorophyll b are both crucial for photosynthesis, and they have complementary absorption spectra.
Correct answer: Absorbed, Reflected754. Due to slight differences in their _, the chlorophyll a and chlorophyll b show slightly different _.
- A. Structure, Absorption spectra
- B. Structure, Molecular formula
- C. Absorption spectra, Structure
- D. Absorption spectra, Molecular formula
Explanation: Chlorophyll a and chlorophyll b differ slightly in their chemical structures, which leads to variations in their absorption spectra.
Correct answer: Structure, Absorption spectra- A. Increase the range of light wavelengths being absorbed
- B. Decrease the range of light wavelengths being absorbed
- C. Have no effect on the range of light wavelengths being absorbed
- D. Have no effect on the color of pigment
Explanation: Option A is correct.Yes, the difference in the structure of different pigments can increase the range of light wavelengths being absorbed.
Correct answer: Increase the range of light wavelengths being absorbed756. Chlorophyll a is:
- A. Yellow - Green
- B. Blue - Green
- C. Blue - Yellow
- D. Yellow - Blue
Explanation: Option B is correct.Chlorophyll a is blue-green. This is because it absorbs blue-green light and reflects red light.
Correct answer: Blue - Green757. Chlorophyll b is:
- A. Yellow - Green
- B. Blue - Yellow
- C. Blue - Green
- D. None of these
Explanation: Option A is correct. Chlorophyll b appears yellow-green because it absorbs light primarily in the blue and yellow regions of the spectrum…
Correct answer: Yellow - Green- A. Chlorophyll a and Chlorophyll b
- B. Carotenoids
- C. Bacteriochlorophyll
- D. Both A and B
Explanation: Option D is correct. Chlorophyll a and chlorophyll b are the primary pigments that capture light energy and drive the light-dependent…
Correct answer: Both A and B- A. Chlorophyll - c
- B. Chlorophyll − a
- C. Bacteriochlorophyll
- D. Carotenoids
Explanation: Option B is correct. Chlorophyll a is the primary pigment responsible for the direct conversion of solar energy into chemical energy…
Correct answer: Chlorophyll − a- A. Several forms
- B. One forms
- C. Two forms
- D. Three forms
Explanation: Option C is correct.Chlorophyll a itself exists in two forms.Protochlorophyllide is the first form of chlorophyll a.
Correct answer: Two forms