MCQOPTIONS
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MCQOPTIONS
This section includes 16 Mcqs, each offering curated multiple-choice questions to sharpen your Biochemistry knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
A purine with an amine (NH) group on the 6 carbon is |
| A. | adenine |
| B. | cytosine |
| C. | thymine |
| D. | guanine |
| Answer» B. cytosine | |
| 2. |
Because DNA is a highly charged polyanion, its stability to heat denaturation |
| A. | does not depend on hydrophobic interactions |
| B. | increases with increasing salt |
| C. | is independent of G - C content |
| D. | decreases with increasing salt |
| Answer» C. is independent of G - C content | |
| 3. |
The sugar in RNA is __________ , the sugar in DNA is __________ |
| A. | deoxyribose, ribose |
| B. | ribose, deoxyribose |
| C. | ribose, phosphate |
| D. | ribose, uracil |
| Answer» C. ribose, phosphate | |
| 4. |
Nucleoside is a pyrimidine or purine base |
| A. | covalently bonded to a sugar |
| B. | ionically bonded to a sugar |
| C. | hydrogen bonded to a sugar |
| D. | none of the above |
| Answer» B. ionically bonded to a sugar | |
| 5. |
In gel electrophoresis, what fragments will move most quickly through a gel? |
| A. | Large fragments |
| B. | Small fragments |
| C. | Large genome |
| D. | None of these |
| Answer» C. Large genome | |
| 6. |
Which pyrimidine base contains an amino group at carbon 4? |
| A. | Cytosine |
| B. | Thymine |
| C. | Uracil |
| D. | Adenine |
| Answer» B. Thymine | |
| 7. |
The unfavourable free energy associated with not satisfying a hydrogen bond after formation of the double helix is approximately |
| A. | 10 kJ/mol |
| B. | 20 kJ/mol |
| C. | 25 kJ/mol |
| D. | 30 kJ/mol |
| Answer» C. 25 kJ/mol | |
| 8. |
The most stabilizing force for nucleic acids is |
| A. | hydrogen bonds |
| B. | electrostatic bond |
| C. | Van der Waals |
| D. | conformational entropy |
| Answer» D. conformational entropy | |
| 9. |
A purine with an amine (NH2) group on the 6th carbon is |
| A. | adenine |
| B. | cytosine |
| C. | thymine |
| D. | guanine |
| Answer» B. cytosine | |
| 10. |
Which of the following is found on RNA but not DNA? |
| A. | Uracil |
| B. | Deoxyribose |
| C. | Phosphate |
| D. | Adenine |
| Answer» B. Deoxyribose | |
| 11. |
Nucleotide bases and aromatic amino acids absorb light respectively at |
| A. | 280 and 260 nm |
| B. | 260 and 280 nm |
| C. | 270 and 280 nm |
| D. | 260 and 270 nm |
| Answer» C. 270 and 280 nm | |
| 12. |
Nucleic acids can be analyzed experimentally by their |
| A. | molecular weight |
| B. | absorption of visible light |
| C. | absorption of uv light |
| D. | none of these |
| Answer» D. none of these | |
| 13. |
Thymidine |
| A. | can participate in hydrophobic interactions due to its methyl group |
| B. | is replaced by uracil in RNA |
| C. | normally forms two hydrogen bonds with adenosine |
| D. | all of the above |
| Answer» E. | |
| 14. |
A nucleotide consists of |
| A. | a sugar, a base and a phosphate |
| B. | a sugar and a phosphate |
| C. | paired bases |
| D. | a sugar, a base and three phosphates |
| Answer» B. a sugar and a phosphate | |
| 15. |
Which of the following is a purine? |
| A. | Cytosine |
| B. | Adenine |
| C. | Thymine |
| D. | Uracil |
| Answer» C. Thymine | |
| 16. |
A five carbon sugar lacking a hydrogen at the number 2 carbon is found in |
| A. | DNA |
| B. | RNA |
| C. | mRNA |
| D. | rDNA |
| Answer» B. RNA | |