MCQOPTIONS
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MCQOPTIONS
This section includes 18 Mcqs, each offering curated multiple-choice questions to sharpen your Biochemistry knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
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 | |
| 2. |
Which of the following accepts only one electron? |
| A. | Cytochrome b |
| B. | Coenzyme Q |
| C. | FMN |
| D. | FAD |
| Answer» B. Coenzyme Q | |
| 3. |
Which one of the following is the one having highest redox potential? |
| A. | Ubiquinone |
| B. | O2 |
| C. | FMN |
| D. | NAD |
| Answer» C. FMN | |
| 4. |
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 into 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 | |
| 5. |
If rotenone is added to the mitochondrial electron transport chain then ____________ |
| A. | Succinate oxidation remains normal |
| B. | P: O ratio of NADH is reduced from 3:1 to 2:1 |
| C. | Oxidative phosphorylation is uncoupled at site I |
| D. | Rate of NADH oxidation is diminished to two-thirds of its initial value |
| Answer» B. P: O ratio of NADH is reduced from 3:1 to 2:1 | |
| 6. |
If the oxidative phosphorylation was uncoupled in the mitochondria then there is a/an ____________ |
| A. | Decreased concentration of ADP in the mitochondria |
| B. | Decreased oxidative rate |
| C. | Increased inorganic phosphate in the mitochondria |
| D. | Decreased production of heat |
| Answer» D. Decreased production of heat | |
| 7. |
If 2, 4-dinitrophenol is added to tightly coupled mitochondria that are actively oxidizing succinate ____________ |
| A. | Electron flow will continue but ATP synthesis will not occur |
| B. | Electron flow will continue but ATP synthesis will be increased |
| C. | Electron flow will cease but ATP synthesis will continue |
| D. | Both electron flow and ATP synthesis will be ceased |
| Answer» B. Electron flow will continue but ATP synthesis will be increased | |
| 8. |
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 | |
| 9. |
OUT_OF_THE_FOLLOWING_THE_ONE_HAVING_HIGHEST_REDOX_POTENTIAL_IS?$ |
| A. | Ubiquinone |
| B. | O<sub>2</sub> |
| C. | FMN |
| D. | NAD |
| Answer» C. FMN | |
| 10. |
Which_of_the_following_accepts_only_one_electron?$ |
| A. | Cytochrome b |
| B. | Coenzyme Q |
| C. | FMN |
| D. | FAD |
| Answer» B. Coenzyme Q | |
| 11. |
Chemiosmotic hypothesis does not involv? |
| 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 | |
| 12. |
Which of the following takes place in substrate level phosphorylation? |
| A. | Oxidation of one molecule of substrate is linked to synthesis of more than one ATP molecule |
| B. | High energy intermediate compounds cannot be isolated |
| C. | Only mitochondrial reactions participate in ATP formation |
| D. | Substrate reacts to form a product containing a high energy bond |
| Answer» E. | |
| 13. |
If rotenone is added to the mitochondrial electron transport chain |
| A. | Succinate oxidation remains normal |
| B. | P: O ratio of NADH is reduced from 3:1 to 2:1 |
| C. | Oxidative phosphorylation is uncoupled at site I |
| D. | Rate of NADH oxidation is diminished to two-thirds of its initial value |
| Answer» B. P: O ratio of NADH is reduced from 3:1 to 2:1 | |
| 14. |
If the oxidative phosphorylation was uncoupled in the mitochondria then there is a/an |
| A. | Decreased concentration of ADP in the mitochondria |
| B. | Decreased oxidative rate |
| C. | Increased inorganic phosphate in the mitochondria |
| D. | Decreased production of heat |
| Answer» D. Decreased production of heat | |
| 15. |
If 2, 4-dinitrophenol is added to tightly coupled mitochondria that are actively oxidizing succinate |
| A. | Electron flow will continue but ATP synthesis will not occur |
| B. | Electron flow will continue but ATP synthesis will be increased |
| C. | Electron flow will cease but ATP synthesis will continue |
| D. | Both electron flow and ATP synthesis will be ceased |
| Answer» B. Electron flow will continue but ATP synthesis will be increased | |
| 16. |
If mitochondria were blocked at the site of NADH oxidation and were treated with succinate as substrate, what would the P : O ratio is? |
| A. | Same as that normally produced by succinate |
| B. | One more than normally produced by succinate |
| C. | One less than normally produced by succinate |
| D. | Zero |
| Answer» B. One more than normally produced by succinate | |
| 17. |
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 | |
| 18. |
Which of the following is the prosthetic group of NADH dehydrogenase? |
| A. | NADH |
| B. | FAD |
| C. | NADPH |
| D. | FMN |
| Answer» E. | |