MCQOPTIONS
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MCQOPTIONS
This section includes 195 Mcqs, each offering curated multiple-choice questions to sharpen your Biochemistry knowledge and support exam preparation. Choose a topic below to get started.
| 101. |
If 8 photons are required to produce one molecule of O₂, how many photons are required to produce one molecule of glucose? |
| A. | 6 |
| B. | 8 |
| C. | 48 |
| D. | 12 |
| Answer» D. 12 | |
| 102. |
The nitrogen atoms of urea produced in the urea cycle are derived from |
| A. | nitrate |
| B. | ammonia and aspartic acid |
| C. | nitrite |
| D. | ammonia |
| Answer» C. nitrite | |
| 103. |
Which of the following is used as carbon atom source while producing urea in the urea cycle? |
| A. | Arginine |
| B. | Aspartic acid |
| C. | Carbon dioxide |
| D. | Glucose |
| Answer» D. Glucose | |
| 104. |
During electron transport, protons are pumped out of the mitochondrion at each of the major sites except for |
| A. | complex I |
| B. | complex II |
| C. | complex III |
| D. | complex IV |
| Answer» C. complex III | |
| 105. |
The products of urea cycle are |
| A. | 1 molecule of urea, 1 molecule of ammonia, 1 molecule of ATP and 1 molecule of fumaric acid |
| B. | 1 molecule of fumaric acid, 1 molecule of urea, 1 molecule of AMP, 2 molecules of ADP |
| C. | 1 molecule of aspartic acid, 1 molecule of ammonia, 1 molecule of fumaric acid, 1 molecule of ATP |
| D. | None of the above |
| Answer» C. 1 molecule of aspartic acid, 1 molecule of ammonia, 1 molecule of fumaric acid, 1 molecule of ATP | |
| 106. |
Which of the following amino acid do not fall under the category of essential amino acid? |
| A. | Histidine |
| B. | Leucine |
| C. | Glycine |
| D. | Methionine |
| Answer» D. Methionine | |
| 107. |
The aerobic breakdown of glucose known as respiration involves |
| A. | electron transport phosphorylation |
| B. | glycolysis |
| C. | Krebs Cycle |
| D. | all of the above |
| Answer» E. | |
| 108. |
During cellular respiration, most of the ATP made, is generated by |
| A. | oxidative phosphorylation |
| B. | photophosphorylation |
| C. | glycolysis |
| D. | substrate-level phosphorylation |
| Answer» B. photophosphorylation | |
| 109. |
To stop ATP synthesis which chemical is generally used? |
| A. | DNSA |
| B. | 2,4 dinitrophenol |
| C. | DDT |
| D. | None of the chemical can stop ATP synthesis |
| Answer» C. DDT | |
| 110. |
Important function of cholesterol is to |
| A. | modulate fluidity |
| B. | enhance blood circulation |
| C. | prevent bile salts formation |
| D. | None of these |
| Answer» B. enhance blood circulation | |
| 111. |
The enzymes of the TCA cycle in a eukaryotic cell are located in the |
| A. | nucleus |
| B. | mitochondria |
| C. | plasma membrane |
| D. | lysosomal bodies |
| Answer» C. plasma membrane | |
| 112. |
Citric acid cycle occurs in |
| A. | cytoplasm |
| B. | mitochondria |
| C. | endoplasmic reticulum |
| D. | golgi bodies |
| Answer» C. endoplasmic reticulum | |
| 113. |
A positive redox potential means substance has |
| A. | lower affinity for electron |
| B. | higher affinity for electron |
| C. | lower affinity for proton |
| D. | higher affinity for proton |
| Answer» C. lower affinity for proton | |
| 114. |
Most of the enzymes of the citric acid cycle in a eukaryotic cell are located in the |
| A. | inner mitochondrial membrane |
| B. | cytosol |
| C. | mitochondrial matrix |
| D. | intermembrane space |
| Answer» D. intermembrane space | |
| 115. |
Most multi-cellular organisms obtain energy for the synthesis of ATP during oxidative phosphorylation from |
| A. | high energy phosphate compounds |
| B. | a proton gradient across the inner mitochondrial membrane |
| C. | a proton gradient across the cell membrane |
| D. | a proton gradient across the outer mitochondrial membrane |
| Answer» C. a proton gradient across the cell membrane | |
| 116. |
The transport of acyl-CoA for oxidation using a shuttle involves formation of the intermediate |
| A. | 3 acetyl-CoA |
| B. | Acyl-coenzyme A |
| C. | acyl-carnitine |
| D. | None of these |
| Answer» D. None of these | |
| 117. |
The three identical b subunits of the F1, complex during ATP synthesis have |
| A. | different affinities for ATP but not for ADP |
| B. | different affinities for ADP but not for ATP |
| C. | different affinities for ATP and for ADP |
| D. | similar affinities for ADP and ATP |
| Answer» D. similar affinities for ADP and ATP | |
| 118. |
The oxidation of methanol (wood alcohol) in human retina tissue indirectly leads to |
| A. | pressure builds up |
| B. | colour blindness |
| C. | blindness |
| D. | all of these |
| Answer» D. all of these | |
| 119. |
Coenzyme Q is involved in electron transport as |
| A. | directly to O₂ |
| B. | a water-soluble electron donor |
| C. | covalently attached cytochrome cofactor |
| D. | a lipid-soluble electron carrier |
| Answer» E. | |
| 120. |
A biological redox reaction always involves |
| A. | an oxidizing agent |
| B. | a gain of electrons |
| C. | a reducing agent |
| D. | all of these |
| Answer» E. | |
| 121. |
FAD is reduced to FADH₂ during |
| A. | electron transport phosphorylation |
| B. | lactate fermentation |
| C. | Krebs cycle |
| D. | glycolysis |
| Answer» D. glycolysis | |
| 122. |
Where the acyl-CoA formed in the cytosol is transported for oxidation? |
| A. | Mitochondrial matrix |
| B. | Microsomes |
| C. | Endoplasmic reticulum |
| D. | Remains in cytosol |
| Answer» B. Microsomes | |
| 123. |
The carbon dioxide is primary a product of |
| A. | Krebs cycle |
| B. | glycolysis |
| C. | electron transport phosphorylation. |
| D. | lactate fermentation. |
| Answer» B. glycolysis | |
| 124. |
How many CO₂ molecules are exhaled for each O₂ molecule utilized in cellular respiration? |
| A. | 1 |
| B. | 3 |
| C. | 6 |
| D. | 12 |
| Answer» B. 3 | |
| 125. |
In aerobic respiration, the compound that enters a mitochondrion is |
| A. | acetyl CoA |
| B. | pyruvate |
| C. | phosphoglyceraldehyde |
| D. | oxaloacetate |
| Answer» C. phosphoglyceraldehyde | |
| 126. |
Which of the following is not a significant biological oxidizing agent? |
| A. | FAD |
| B. | Fe³⁺ |
| C. | O₂ |
| D. | NAD⁺ |
| Answer» C. O₂ | |
| 127. |
The earliest photo synthesizers used which of the following as the source of hydrogen? |
| A. | CO₂ |
| B. | C₆H₁₂O₆ |
| C. | H₂O |
| D. | H₂S |
| Answer» E. | |
| 128. |
Which of the following systems has an associated water splitting activity resembling that of plants? |
| A. | Photosystem |
| B. | Photosystem I |
| C. | Photosystem II |
| D. | Photosystem III |
| Answer» D. Photosystem III | |
| 129. |
The carbon-assimilation reactions require ATP and NADPH in the ratio |
| A. | 3:2 |
| B. | 2:3 |
| C. | 3:4 |
| D. | 4:3 |
| Answer» B. 2:3 | |
| 130. |
What happens after glycolysis when oxygen is available as an electron acceptor? |
| A. | Pyruvate is formed |
| B. | NADH is produced |
| C. | Fermentation |
| D. | Oxidative phosphorylation |
| Answer» C. Fermentation | |
| 131. |
The complete oxidation of glucose yields usable energy in the form of |
| A. | FADH₂ |
| B. | coenzyme A |
| C. | ATP |
| D. | pyruvic acid |
| Answer» D. pyruvic acid | |
| 132. |
In electron transport, electrons ultimately pass to |
| A. | ADP |
| B. | cytochrome b |
| C. | oxygen |
| D. | none of these |
| Answer» D. none of these | |
| 133. |
Which one of the following is not the intermediate of Kreb's cycle? |
| A. | Isocitrate |
| B. | Succinate |
| C. | Fumarate |
| D. | Stearate |
| Answer» E. | |
| 134. |
Lactic acid is produced by human muscles during strenuous exercise because of lack of |
| A. | oxygen |
| B. | NAD⁺ |
| C. | glucose |
| D. | ADP and Pi |
| Answer» B. NAD⁺ | |
| 135. |
The FADH₂ and NADH produced by the oxidation of one acetyl-CoA results in the synthesis of about- |
| A. | 3 ATPs |
| B. | 6 ATPs |
| C. | 11 ATPs |
| D. | 15 ATPs |
| Answer» D. 15 ATPs | |
| 136. |
The only membrane bound enzyme in the citric acid cycle is _________ |
| A. | Succinate dehydrogenase |
| B. | NADH dehydrogenase |
| C. | ATP synthase |
| D. | Acyl co-A dehydrogenase |
| Answer» B. NADH dehydrogenase | |
| 137. |
Standard redox potential for a substance is measured under standard condition and is expressed as |
| A. | mili-Ampere |
| B. | Volt |
| C. | without unit |
| D. | Ohm |
| Answer» C. without unit | |
| 138. |
A lipid-soluble benzoquinone with a long isoprenoid side chain is? |
| A. | Ubiquinone |
| B. | Cytochrome b |
| C. | Cytochrome c |
| D. | Cytochrome a |
| Answer» B. Cytochrome b | |
| 139. |
How many molecules of ATPs are synthesized per NADH oxidation? |
| A. | 2 |
| B. | 1 |
| C. | 3 |
| D. | 4 |
| Answer» D. 4 | |
| 140. |
If the oxygen is labeled in CO₂ and provide this CO₂ to a plant, where it is expected to find this labeled oxygen after the plant had undergone photosynthesis? |
| A. | In the water used |
| B. | In the NADPH |
| C. | In the carbohydrate produced |
| D. | In the oxygen given off by the plant |
| Answer» D. In the oxygen given off by the plant | |
| 141. |
ATP synthesis by chemiosmosis is by |
| A. | ATP dehydrogenase |
| B. | Gyrase |
| C. | ATP synthase |
| D. | Dehydrogenase |
| Answer» D. Dehydrogenase | |
| 142. |
Oxysomes or F₀– F₁ particles occur on |
| A. | Inner mitochondrial membrane |
| B. | Chloroplast surface |
| C. | Mitochondrial surface |
| D. | Thylakoids |
| Answer» B. Chloroplast surface | |
| 143. |
A mobile, lipid soluble carrier of two electrons present in mitochondria is |
| A. | PQʙ |
| B. | Q |
| C. | Cytochrome c |
| D. | Plastocyanin |
| Answer» C. Cytochrome c | |
| 144. |
The end product of glycolysis is pyruvate, which enters the citric acid cycle after being converted to |
| A. | acetic acid |
| B. | acetyl-CoA |
| C. | acetaldehyde |
| D. | none of these |
| Answer» C. acetaldehyde | |
| 145. |
Oxidation of a molecule involves |
| A. | gain of electron |
| B. | loss of electron |
| C. | gain of proton |
| D. | loss of proton |
| Answer» C. gain of proton | |
| 146. |
Which of the following is the reduced form of a temporary electron carrier molecule? |
| A. | FADH₂ |
| B. | ATP |
| C. | NADP+ |
| D. | CO₂ |
| Answer» B. ATP | |
| 147. |
Long-chain fatty acids are oxidized step-wise in one carbon units starting from |
| A. | Carboxyl end |
| B. | Aliphatic end |
| C. | a and b |
| D. | None of the mentioned |
| Answer» B. Aliphatic end | |
| 148. |
Typically how many copies of DNA is/are there in each mitochondrion? |
| A. | 1 |
| B. | 11 |
| C. | 10 |
| D. | 12 |
| Answer» D. 12 | |
| 149. |
The cytochrome c oxidase complex |
| A. | accepts electrons from cyt c |
| B. | donates four electrons to O₂ |
| C. | pumps protons out of the matrix space |
| D. | all of these |
| Answer» E. | |
| 150. |
In metabolism, NAD is involved in |
| A. | Spontaneous reaction |
| B. | Elimination reaction |
| C. | Redox reactions |
| D. | None of the mentioned |
| Answer» D. None of the mentioned | |