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.
| 151. |
Which of the following is correct sequence of processes in the oxidation of glucose? |
| A. | Krebs cycle - glycolysis - electron transport |
| B. | Glycolysis - Krebs cycle - eletron transport |
| C. | Electron transport - Krebs cycle - glycolysis |
| D. | Krebs cycle - electron transport - glycolysis |
| Answer» C. Electron transport - Krebs cycle - glycolysis | |
| 152. |
Which of the following is the correct sequence for the movement of electrons during the light-dependent reactions of plants? |
| A. | P₇₀₀, P₆₈₀, NADP⁺, water |
| B. | P₆₈₀, water, P₇₀₀, NADP⁺ |
| C. | Water, P₇₀₀, NADP⁺, P₆₈₀ |
| D. | Water,P₆₈₀, P₇₀₀, NADP⁺ |
| Answer» E. | |
| 153. |
A chlorophyll-like accessory pigment lacking Mg⁺² is |
| A. | Pheophytin |
| B. | Cytochrome c |
| C. | Plastocyanin |
| D. | Ferredoxin |
| Answer» B. Cytochrome c | |
| 154. |
Photosystem I uses which of the following in its photo-center? |
| A. | P700 |
| B. | P800 |
| C. | P900 |
| D. | P600 |
| Answer» B. P800 | |
| 155. |
Which one is not the main protein in electron transport chain? |
| A. | NADH dehydrogenase |
| B. | Cytochrome bc1 complex |
| C. | Cytochrome oxidase |
| D. | Citrate synthease |
| Answer» E. | |
| 156. |
The magnitude of proton motive force depends on |
| A. | Energy charge of cell |
| B. | Permeability of membrane |
| C. | Number of ribosomes in cell |
| D. | None of the mentioned |
| Answer» B. Permeability of membrane | |
| 157. |
The rate of electron transfer when proton motive force is high is |
| A. | Faster |
| B. | Slower |
| C. | Moderate |
| D. | None of the mentioned |
| Answer» C. Moderate | |
| 158. |
In mitochondria, hydride ions are removed from substrates by _________ |
| A. | NAD-linked dehydrogenases |
| B. | NADP-linked dehydrogenases |
| C. | ATP synthase |
| D. | Succinate dehydrogenases |
| Answer» B. NADP-linked dehydrogenases | |
| 159. |
Photosynthesis takes place in sac like membranes called |
| A. | Thylakoids |
| B. | Grana |
| C. | Photosystems |
| D. | Photons |
| Answer» B. Grana | |
| 160. |
How many mitochondrial proteins are encoded in nuclear genes and imported into mitochondria after their synthesis? |
| A. | 600 |
| B. | 700 |
| C. | 800 |
| D. | 900 |
| Answer» E. | |
| 161. |
The electrons that are released by the splitting of water during photosynthesis ultimately end up in |
| A. | ATP |
| B. | O₂ |
| C. | NADPH |
| D. | rubisco |
| Answer» D. rubisco | |
| 162. |
Where does the O₂ come from that is essential for the proper functioning of oxidative phosphorylation? |
| A. | Fermentation |
| B. | Light reactions of photosynthesis |
| C. | Dark reactions of photosynthesis |
| D. | Carbon fixation |
| Answer» C. Dark reactions of photosynthesis | |
| 163. |
Out of the following the one having highest redox potential is |
| A. | Ubiquinone |
| B. | O₂ |
| C. | FMN |
| D. | NAD |
| Answer» C. FMN | |
| 164. |
The mechanism of action of cyanide, a mitochondrial toxin, is by inhibiting |
| A. | ATP synthase |
| B. | Succinate dehydrogenase |
| C. | Cytochrome c oxidase |
| D. | NADH dehydrogenase |
| Answer» D. NADH dehydrogenase | |
| 165. |
What is the effect of excessive rate of apoptosis? |
| A. | Atrophy |
| B. | Sneezing |
| C. | Fever |
| D. | AIDS |
| Answer» B. Sneezing | |
| 166. |
The light reaction of photosynthesis takes place in |
| A. | Inner membrane of chloroplast |
| B. | Outer membrane of chloroplast |
| C. | Stroma |
| D. | Matrix |
| Answer» B. Outer membrane of chloroplast | |
| 167. |
Which of the following is the distinguishable feature of cyclic photophosphorylation? |
| A. | Phosphorylation only takes place |
| B. | Phosphorylation and photolysis take place |
| C. | Photolysis of water is taking place |
| D. | None of the mentioned |
| Answer» B. Phosphorylation and photolysis take place | |
| 168. |
Urea cycle converts |
| A. | ammonia into a less toxic form |
| B. | ketoacids into amino acids |
| C. | amino acids into ketoacids |
| D. | none of these |
| Answer» B. ketoacids into amino acids | |
| 169. |
Which of the following is not a feature of oxidative phosphorylation? |
| A. | Direct transfer of phosphate from a substrate molecule to ADP |
| B. | An electrochemical gradient across the inner mitochondrial membrane |
| C. | A membrane bound ATP synthase |
| D. | A protonmotive force |
| Answer» B. An electrochemical gradient across the inner mitochondrial membrane | |
| 170. |
During glycolysis, electrons removed from glucose are passed to |
| A. | FAD |
| B. | NAD+ |
| C. | acetyl CoA |
| D. | pyruvic acid |
| Answer» C. acetyl CoA | |
| 171. |
In eukaryotes, electron transport occurs in |
| A. | membranes and mitochondria |
| B. | endoplasmic reticulum |
| C. | cytoplasm |
| D. | all of the above |
| Answer» B. endoplasmic reticulum | |
| 172. |
Photosynthesis can be described as |
| A. | Reductive, anabolic, endergonic process |
| B. | Reductive, anabolic, exergonic process |
| C. | Oxidative, anabolic, endergonic process |
| D. | Oxidative, catabolic, exergonic process |
| Answer» B. Reductive, anabolic, exergonic process | |
| 173. |
Effect of valinomycin on oxidative phosphorylation does not involve |
| A. | pH gradient across the inner mitochondrial membrane decreases |
| B. | Rate of flow of electrons increases |
| C. | Rate of oxygen consumption increases |
| D. | Net yield of ATP decreases |
| Answer» B. Rate of flow of electrons increases | |
| 174. |
The manufacture of ATP in both photosynthesis and respiration is made possible by |
| A. | the existence of a proton gradient across specific membranes |
| B. | the action of ATP synthase |
| C. | energy from the movement of electrons |
| D. | All of the above |
| Answer» E. | |
| 175. |
Mitochondrial DNA is a |
| A. | Simple, single stranded linear DNA molecule |
| B. | Simple, single stranded circular DNA molecule |
| C. | Simple, double stranded linear DNA molecule |
| D. | Simple, double stranded circular DNA molecule |
| Answer» E. | |
| 176. |
Chemiosmotic hypothesis does not involve |
| A. | Only proton transport is strictly regulated, other positively charged ions can diffuse freely across the mitochondrial membrane |
| B. | ATPase activity is reversible |
| C. | Proton flow in to the mitochondria depends on the presence of ADP and Pi |
| D. | Electron transport by the respiratory chain pumps protons out of the mitochondria |
| Answer» B. ATPase activity is reversible | |
| 177. |
In the initial step of photosynthesis, sunlight energizes the electron pair of |
| A. | adenosine triphosphate (ATP) |
| B. | chlorophyll pigments |
| C. | water |
| D. | carbon dioxide |
| Answer» C. water | |
| 178. |
How many ATPs are produced during citric acid cycle? |
| A. | 10 |
| B. | 13 |
| C. | 12 |
| D. | 8 |
| Answer» D. 8 | |
| 179. |
In oxygenic photosynthesis, water is split in order to provide the |
| A. | electrons needed to reduce P680 |
| B. | O₂ needed for the dark reactions |
| C. | electrons needed to reduce NADH |
| D. | electrons needed for cyclic photophosphorylation |
| Answer» B. O₂ needed for the dark reactions | |
| 180. |
Which of the following group of plants contains agranal chloroplast? |
| A. | C₃ plants |
| B. | C₄ plants |
| C. | C₂ plants |
| D. | C₁ plants |
| Answer» C. C₂ plants | |
| 181. |
A eukaryotic cell that can carry out only fermentation instead of the complete aerobic respiration of glucose |
| A. | produces less CO₂ |
| B. | is lacking in O₂ |
| C. | has mitochondria present |
| D. | all of these |
| Answer» E. | |
| 182. |
How many molecules of ATP are hydrolysed to form two molecule of ammonia? |
| A. | 10 |
| B. | 5 |
| C. | 16 |
| D. | 15 |
| Answer» D. 15 | |
| 183. |
Each cycle of β-oxidation produces |
| A. | 1 FADH₂, 1 NAD+, and 1 acetyl-CoA |
| B. | 1 FADH₂, 1 NADH and 1 acetyl-CoA |
| C. | 1 FADH₂, 1 NADH and 2 CO₂ molecules |
| D. | 1 FAD, 1 NAD+ and 2 CO₂ molecules |
| Answer» C. 1 FADH₂, 1 NADH and 2 CO₂ molecules | |
| 184. |
Three identical β subunits of the F1 complex during ATP synthesis have |
| A. | Different affinities for ATP and ADP |
| B. | Similar affinities for ADP and ATP |
| C. | Different affinities for ADP but not ATP |
| D. | Different affinities for ATP but not ADP |
| Answer» B. Similar affinities for ADP and ATP | |
| 185. |
The inputs to one cycle of the urea cycle are |
| A. | 1 molecule of aspartic acid, 1 molecule of ammonia, 1 molecule of carbon dioxide, 3 molecules of ATP |
| B. | 1 molecule of urea, 1 molecule of ammonia, 3 molecules of ATP and 1 molecule of fumaric acid |
| C. | 1 molecule of fumaric acid, 1 molecule of urea, 3 molecules of AMP |
| D. | None of the above |
| Answer» B. 1 molecule of urea, 1 molecule of ammonia, 3 molecules of ATP and 1 molecule of fumaric acid | |
| 186. |
The maximum energy per gram on oxidization is yielded from |
| A. | fat |
| B. | protein |
| C. | glycogen |
| D. | starch |
| Answer» B. protein | |
| 187. |
Which one of the following is true about C₃ plants? |
| A. | First stable product is phosphoglyceric acid |
| B. | Photosynthetically more efficient |
| C. | More efficient in CO₂ fixation than C₄ plants |
| D. | None of the mentioned |
| Answer» B. Photosynthetically more efficient | |
| 188. |
In oxygenic photosynthesis, the electron donor is |
| A. | water |
| B. | oxygen |
| C. | NADH |
| D. | NADPH |
| Answer» B. oxygen | |
| 189. |
Nitrate reduction can be carried out by |
| A. | only microorganism |
| B. | plant and microorganism |
| C. | only plants |
| D. | none of these |
| Answer» C. only plants | |
| 190. |
The breakdown of glucose occurs by the process known as |
| A. | glycolysis |
| B. | fermentation |
| C. | anaerobic respiration |
| D. | Krebs cycle |
| Answer» B. fermentation | |
| 191. |
The oxidation of methanol (wood alcohol) in human retina tissue leads directly to the formation of |
| A. | formaldehyde |
| B. | sugars |
| C. | CO₂ |
| D. | none of these |
| Answer» B. sugars | |
| 192. |
How many molecules of acetyl-CoA are produced in oxidation of palmitic acid (C₁₆), which involves seven rounds of oxidation? |
| A. | 6 |
| B. | 7 |
| C. | 8 |
| D. | 9 |
| Answer» D. 9 | |
| 193. |
Long-chain fatty acids are oxidized step-wise in one carbon units starting from the |
| A. | carboxyl end |
| B. | aliphatic end |
| C. | both (a) and (b) |
| D. | none of these |
| Answer» B. aliphatic end | |
| 194. |
The irreversibility of the thiokinase reactions (formation of initial acyl-CoA) |
| A. | make this activation reaction the committed step on the pathway |
| B. | is due to the subsequent hydrolysis of the product |
| C. | applies only to even-chain fatty acids |
| D. | both (a) and (b) |
| Answer» E. | |
| 195. |
Membrane potential and the proton gradient |
| A. | are both required to make ATP |
| B. | are sufficient, separately, to make ATP from ADP + Pi; |
| C. | reinforce one another when respiratory inhibitors are present |
| D. | cancel one another when uncouplers are present |
| Answer» B. are sufficient, separately, to make ATP from ADP + Pi; | |