MCQOPTIONS
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MCQOPTIONS
This section includes 79 Mcqs, each offering curated multiple-choice questions to sharpen your Nucleic Acid Structure knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
Histones |
| A. | are negatively-charged globular proteins. |
| B. | contain both -helix and -pleated sheet. |
| C. | have molecular weights in excess of 100,000 |
| D. | contain high amounts of basic amino acids. |
| Answer» E. | |
| 2. |
Which is a characteristic of eukaryotic genetic material? |
| A. | Eukaryotic genetic material consists of supercoiled circular DNA molecules complexed with proteins into chromosomes. |
| B. | Eukaryotic genetic material consists of relaxed linear DNA molecules complexed with RNA into a 30 nm fiber. |
| C. | Eukaryotic genetic material is compacted by wrapping the double-helix around histone proteins to form nucleosomes |
| D. | Eukaryotic genetic material is compacted by folding linker regions around non-histone proteins to form a scaffold. |
| Answer» D. Eukaryotic genetic material is compacted by folding linker regions around non-histone proteins to form a scaffold. | |
| 3. |
Which is a property of both viral genetic material and bacterial genetic material? |
| A. | Both can be double-stranded, circular DNA. |
| B. | Both can be single-stranded, linear RNA. |
| C. | Both can be compacted into inverted repeats. |
| D. | Both can be compacted into plasmids. |
| Answer» B. Both can be single-stranded, linear RNA. | |
| 4. |
If the following experimental results were obtained, which would be evidence against DNA being the genetic material? |
| A. | The base composition of DNA is the same in two different cells of the same organism. |
| B. | The viral components labeled with 32P remain outside the cell during a successful infection. |
| C. | The transforming factor isolated from a virulent bacterium is sensitive to deoxyribonucleases. |
| D. | The base composition of DNA in an organism remains constant as the organism ages. |
| Answer» C. The transforming factor isolated from a virulent bacterium is sensitive to deoxyribonucleases. | |
| 5. |
Which property is shared by the five histone proteins? |
| A. | They are acidic proteins with relatively large molecular weights. |
| B. | They are multimeric proteins with high levels of Arg and Lys |
| C. | They are fibrous proteins with high amounts of -helix. |
| D. | They are globular proteins with a positive charge. |
| Answer» E. | |
| 6. |
Which of the following protein is the component of nucleoprotein? |
| A. | Proline |
| B. | Arginine |
| C. | Histones |
| D. | All of the above |
| Answer» D. All of the above | |
| 7. |
Which of the following statements is not true about RNA? |
| A. | Does not have a double stranded structure |
| B. | Thymine is present |
| C. | Does not obey Chargaff s rule |
| D. | The sugar contained in RNA is a ribose |
| Answer» C. Does not obey Chargaff s rule | |
| 8. |
Which of the following is true about Z-DNA helix? |
| A. | It has alternating GC sequences |
| B. | It is a permanent conformation of DNA |
| C. | It tends to be found at the 3 end of the genes |
| D. | It has fewer base pairs per turn than B-DNA |
| Answer» B. It is a permanent conformation of DNA | |
| 9. |
What is the full form of AMP? |
| A. | Adenine mini-phosphate |
| B. | Aldehyde mono-phosphate |
| C. | Alcohol mono-phosphate |
| D. | None of the above |
| Answer» E. | |
| 10. |
Which one of the following nucleic acids has a left handed helix? |
| A. | M-RNA |
| B. | T-RNA |
| C. | A-DNA |
| D. | Z-DNA |
| Answer» E. | |
| 11. |
Which of the following leads to disruption of nucleosomal structure? |
| A. | Acetylation |
| B. | Carboxylation |
| C. | Phosphorylation |
| D. | Methylation |
| Answer» E. | |
| 12. |
Arrangement of nucleotides in DNA can be seen by ____________ |
| A. | Ultracentrifuge |
| B. | X-Ray crystallography |
| C. | Light microscope |
| D. | Electron microscope |
| Answer» C. Light microscope | |
| 13. |
According to Chargaff s rule, in a DNA molecule ____________ |
| A. | The amount of adenine and thymine is equal to the amount of guanine and cytosine |
| B. | The amount of adenine and guanine is equal to the amount of thymine and cytosine |
| C. | The amount of adenine and uracil is equal to the amount of guanine and cytosine |
| D. | The amount of adenine and guanine is equal to the amount of uracil and cytosine |
| Answer» B. The amount of adenine and guanine is equal to the amount of thymine and cytosine | |
| 14. |
In most of the nucleotides, the phosphate group is attached to which carbon of pentose sugar? |
| A. | C-1 |
| B. | C-2 |
| C. | C-4 |
| D. | C-5 |
| Answer» E. | |
| 15. |
Which of the following statement is NOT true? |
| A. | Works as chemical messenger |
| B. | Co-enzymes |
| C. | Co-factors |
| D. | Energy carries |
| Answer» C. Co-factors | |
| 16. |
Match the following- 9. Where is DNA present? |
| A. | Mitochondria |
| B. | Nucleus |
| C. | Cytoplasm |
| D. | Both A and B |
| Answer» B. Nucleus | |
| 17. |
Which ratio is constant for DNA? |
| A. | A + G / T + C |
| B. | A + T / G + C |
| C. | A + C / U + G |
| D. | A + U / G + C |
| Answer» B. A + T / G + C | |
| 18. |
Where is RNA present? |
| A. | Mitochondria |
| B. | Nucleolus |
| C. | Cytoplasm |
| D. | Both B and C |
| Answer» E. | |
| 19. |
Which of the following is pyrimidine nucleotide? |
| A. | Uracil |
| B. | Cytosine |
| C. | Thymine |
| D. | All of the above |
| Answer» E. | |
| 20. |
Which of the following is not present in RNA? |
| A. | uracil |
| B. | adenine |
| C. | thymine |
| D. | guanine |
| Answer» D. guanine | |
| 21. |
If the compound does not contain the phosphate group, it is known as? |
| A. | Nucleotide |
| B. | Nucleoside |
| C. | Both |
| D. | None |
| Answer» C. Both | |
| 22. |
Which of the following is purine nucleotide? |
| A. | Adenine |
| B. | Uracil |
| C. | Thymine |
| D. | All of the above |
| Answer» B. Uracil | |
| 23. |
Number of hydrogen bonds between adenine and thymine? |
| A. | 1 |
| B. | 2 |
| C. | 3 |
| D. | 4 |
| Answer» C. 3 | |
| 24. |
Number of hydrogen bonds between guanine and cytosine? |
| A. | 1 |
| B. | 2 |
| C. | 3 |
| D. | 4 |
| Answer» D. 4 | |
| 25. |
nucleotides have how many components? |
| A. | 2 |
| B. | 3 |
| C. | 4 |
| D. | 5 |
| Answer» C. 4 | |
| 26. |
Nucleotides are linked together to form nucleic acid through which type of bond? |
| A. | Glycosidic bond |
| B. | Phosphor-di-ester bond |
| C. | Both |
| D. | None |
| Answer» C. Both | |
| 27. |
Nucleic acids combine with which biomolecule? |
| A. | Fats |
| B. | Carbohydrates |
| C. | Lipids |
| D. | Proteins |
| Answer» E. | |
| 28. |
Which of the following double-stranded DNA molecules would denature at about the same temperature as the double-stranded molecule containing a 5 -(GA)20-3 strand? |
| A. | a molecule which contains a (GC)20 strand |
| B. | a molecule which contains a (TA)20 strand |
| C. | a molecule which contains a (GACT)10 strand |
| D. | a molecule which contains a (GGGA)10 strand |
| Answer» D. a molecule which contains a (GGGA)10 strand | |
| 29. |
Which of the following forces can stabilize a normal DNA double-helix? |
| A. | Base-stacking is a non-covalent interaction that occurs between the relatively hydrophobic bases in the interior of the helix. |
| B. | Base-pairing is a non-covalent interaction that occurs between adjacent bases in the same strand of the DNA molecule. |
| C. | The hydrophilic sugar-phosphate groups are on the exterior of the helix where they can interact with each other. |
| D. | The deoxyribose rings form N-glycosidic bonds with the phosphate groups that link neighboring nucleotides. |
| Answer» B. Base-pairing is a non-covalent interaction that occurs between adjacent bases in the same strand of the DNA molecule. | |
| 30. |
When this single strand binds to a complementary DNA strand to form a B-DNA structure, |
| A. | half the base-pairs will be A-G pairs and half will be C-T pairs. |
| B. | each base will form at least two hydrogen bonds with a base in the opposite strand. |
| C. | the two strands will form an antiparallel left-handed helix with 12 basepairs per turn. |
| D. | there will be covalent phosphodiester bonds between the two strands. |
| Answer» C. the two strands will form an antiparallel left-handed helix with 12 basepairs per turn. | |
| 31. |
When this single strand binds to a complementary DNA strand, |
| A. | the complementary strand has the sequence 5 -(CT)20-3 and a cruciform structure could form. |
| B. | the complementary strand has the sequence 5 -(CT)20-3 and a Z-DNA structure could form. |
| C. | the complementary strand has the sequence 5 -(TC)20-3 and an H-DNA structure could form. |
| D. | the complementary strand has the sequence 5 -(TC)20-3 and a hairpin structure could form. |
| Answer» D. the complementary strand has the sequence 5 -(TC)20-3 and a hairpin structure could form. | |
| 32. |
Which of the following nucleotides is not present in DNA? |
| A. | AMP |
| B. | GMP |
| C. | CMP |
| D. | UMP |
| Answer» E. | |
| 33. |
Which of the following nucleotides is not present in RNA? |
| A. | AMP |
| B. | GMP |
| C. | CMP |
| D. | TMP |
| Answer» E. | |
| 34. |
Which of the following is false about denaturation? |
| A. | Disruption of hydrogen bonds |
| B. | Disruption of phosphodiester linkage |
| C. | Loss of helical structure of DNA |
| D. | It is resulted as a result of change in pH or increase in temperature |
| Answer» C. Loss of helical structure of DNA | |
| 35. |
DNA denaturation is measured by absorbance at ___________ |
| A. | 220nm |
| B. | 230nm |
| C. | 250nm |
| D. | 260nm |
| Answer» E. | |
| 36. |
What happens in hyperchromicity? |
| A. | When DNA is in bound form, there is decrease in absorption of UV light |
| B. | When DNA is in bound form, there is increase in absorption of UV light |
| C. | When DNA is in unbound form, it is more stable |
| D. | When DNA is in unbound form, there is increase in absorption of UV light |
| Answer» E. | |
| 37. |
What happens in hypochromicity? |
| A. | When DNA is in bound form, there is decrease in absorption of UV light |
| B. | When DNA is in bound form, there is increase in absorption of UV light |
| C. | When DNA is in unbound form, it is more stable |
| D. | When DNA is in unbound form, there is decrease in absorption of UV light |
| Answer» B. When DNA is in bound form, there is increase in absorption of UV light | |
| 38. |
Which of the following involves carrying genetic information from DNA for protein synthesis? |
| A. | |
| B. | B. |
| C. | C. |
| D. | D. |
| Answer» B. B. | |
| 39. |
Identify the purine base of nucleic acids in the following. |
| A. | Cytosine |
| B. | Thymine |
| C. | Uracil |
| D. | Adenine |
| Answer» E. | |
| 40. |
Which structural feature is shared by both uracil and thymine? |
| A. | Both contain two keto groups. |
| B. | Both contain one methyl group. |
| C. | Both contain a five-membered ring. |
| D. | Both contain three nitrogen atoms. |
| Answer» B. Both contain one methyl group. | |
| 41. |
Purine base found in RNA is |
| A. | Cytosine |
| B. | Thymine |
| C. | Guanine |
| D. | Uracil |
| Answer» D. Uracil | |
| 42. |
Which of the following nucleotide contains only ribose sugar and not deoxyribose? |
| A. | Thymine pentose sugar-phosphate |
| B. | Uracil pentose sugar-phosphate |
| C. | Thymine pentose sugar-phosphate |
| D. | Cytosine pentose sugar-phosphate |
| Answer» C. Thymine pentose sugar-phosphate | |
| 43. |
The sugar molecule present in nucleotide is |
| A. | triose |
| B. | tetrose |
| C. | pentose |
| D. | hexose |
| Answer» D. hexose | |
| 44. |
Find the correct statement about phosphodiester linkage between adjacent nucleotides in nucleic acids |
| A. | 3 -phosphate of one nucleotide joins the 3 -hydroxyl of the next nucleotide |
| B. | 3 -phosphate of one nucleotide joins the 5 -hydroxyl of the next nucleotide |
| C. | 5 -phosphate of one nucleotide joins the 5 -hydroxyl of the next nucleotide |
| D. | 5 -phosphate of one nucleotide joins the 3 -hydroxyl of the next nucleotide |
| Answer» E. | |
| 45. |
Nucleoside contains |
| A. | base-sugar |
| B. | base-phosphate |
| C. | base-sugar-phosphate |
| D. | sugar-phosphate |
| Answer» B. base-phosphate | |
| 46. |
ATP is a |
| A. | nucleoside |
| B. | nucleotide |
| C. | vitamin |
| D. | nucleic acid |
| Answer» C. vitamin | |
| 47. |
A phosphodiester bond is present in |
| A. | Nucleic acids in a nucleotide |
| B. | Monosaccharides in a polysaccharide |
| C. | Amino acids in a polypeptide |
| D. | Fatty acids in a diglyceride |
| Answer» B. Monosaccharides in a polysaccharide | |
| 48. |
Building blocks of nucleic acids are ____________ |
| A. | Nucleotides |
| B. | Nucleosides |
| C. | Amino acids |
| D. | Histones |
| Answer» B. Nucleosides | |
| 49. |
Which of the following is false about purine and pyrimidine bases? |
| A. | They are hydrophobic and relatively insoluble in water at the near-neutral pH of the cell |
| B. | At acidic or alkaline pH the bases become charged and their solubility in water increases |
| C. | Purines have two rings in their structure, but pyrimidine bases have only one ring |
| D. | At acidic or alkaline pH the bases become charged and their solubility in water decreases |
| Answer» E. | |
| 50. |
Group of adjacent nucleotides are joined by ____________ |
| A. | Phosphodiester bond |
| B. | Peptide bond |
| C. | Ionic bond |
| D. | Covalent bond |
| Answer» B. Peptide bond | |