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.
| 51. |
What is the composition of nucleotide? |
| A. | a sugar + a phosphate |
| B. | a base + a sugar |
| C. | a base + a phosphate |
| D. | a base + a sugar + phosphate |
| Answer» E. | |
| 52. |
What is the composition of nucleoside? |
| A. | a sugar + a phosphate |
| B. | a base + a sugar |
| C. | a base + a phosphate |
| D. | a base + a sugar + phosphate |
| Answer» C. a base + a phosphate | |
| 53. |
Which of the following are not the components of RNA? |
| A. | Thymine |
| B. | Adenine |
| C. | Guanine |
| D. | Cytosine |
| Answer» B. Adenine | |
| 54. |
Which of the following is true about phosphodiester linkage? |
| A. | 5 -phosphate group of one nucleotide unit is joined to the 3 -hydroxyl group of the next nucleotide |
| B. | 3 -phosphate group of one nucleotide unit is joined to the 5 -hydroxyl group of the next nucleotide |
| C. | 5 -phosphate group of one nucleotide unit is joined to the 5 -hydroxyl group of the next nucleotide |
| D. | 3 -phosphate group of one nucleotide unit is joined to the 3 -hydroxyl group of the next nucleotide |
| Answer» B. 3 -phosphate group of one nucleotide unit is joined to the 5 -hydroxyl group of the next nucleotide | |
| 55. |
The sugar molecule in a nucleotide is ____________ |
| A. | Pentose |
| B. | Hexose |
| C. | Tetrose |
| D. | Triose |
| Answer» B. Hexose | |
| 56. |
A DNA segment contains 100 Adenine and 100 cytosines, how many nucleotides are present in the segment? |
| A. | 100 |
| B. | 200 |
| C. | 400 |
| D. | 50 |
| Answer» D. 50 | |
| 57. |
Nucleic acids are a polymer of nucleotide monomeric units. Each nucleotide consists of |
| A. | base -sugar- OH |
| B. | sugar- phosphate |
| C. | base -sugar- phosphate |
| D. | (base -sugar -phosphate)x |
| Answer» D. (base -sugar -phosphate)x | |
| 58. |
Uridine present in RNA is |
| A. | nucleotides |
| B. | pyrimidine |
| C. | purine |
| D. | nucleoside |
| Answer» E. | |
| 59. |
Which will be a characteristic of this one single strand? |
| A. | The single-stranded chain will contain both ribose and deoxyribose |
| B. | The single-stranded chain will contain both purines and pyrimidines. |
| C. | The single-stranded chain will contain one 5 -end and one 3 -end. |
| D. | The single-stranded chain will contain multiple phosphodiester bonds each linking a 2 -carbon and a 5 -carbon. |
| Answer» D. The single-stranded chain will contain multiple phosphodiester bonds each linking a 2 -carbon and a 5 -carbon. | |
| 60. |
Which of the following double-stranded DNA molecules would denature at a lower temperature than the 40 base-pair double-stranded molecule described above? |
| A. | a 40 base-pair molecule in which 25% of the bases are adenines |
| B. | a 30 base-pair molecule in which 40% of the bases are guanines |
| C. | a 20 base-pair molecule in which 10% of the bases are thymines |
| D. | a 10 base-pair molecule in which 20 % of the bases are cytosines |
| Answer» E. | |
| 61. |
Which characteristic will this double-stranded DNA molecule share with a double-stranded RNA molecule of the same size? |
| A. | Both will have secondary structure. |
| B. | Both will contain inverted repeats. |
| C. | Both will contain inverted repeats. |
| D. | Both will contain four types of base-pairs. |
| Answer» B. Both will contain inverted repeats. | |
| 62. |
Which force can stabilize a DNA double-helix? |
| A. | Hydrophobic bases are found in the interior of the helix where each base- pair is stabilized by the same number of hydrogen bonds. |
| B. | Hydrophilic sugar-phosphate groups are found on the exterior of the helix where they can interact with water. |
| C. | Non-covalent N-glycosidic bonds can form between nitrogenous bases in opposite strands in the helix. |
| D. | Covalent base-stacking interactions can occur between adjacent bases within the same strand in the helix. |
| Answer» C. Non-covalent N-glycosidic bonds can form between nitrogenous bases in opposite strands in the helix. | |
| 63. |
Which characteristic does this double-stranded molecule have when it forms a B- DNA structure? |
| A. | The two strands will have parallel orientation and identical sequences |
| B. | The helix will be right-handed with 12 base-pairs per turn. |
| C. | Every base-pair will contain one purine and one pyrimidine. |
| D. | There are both covalent and non-covalent bonds between the two chains. |
| Answer» D. There are both covalent and non-covalent bonds between the two chains. | |
| 64. |
Which is a possible sequence and structure for this DNA molecule? |
| A. | If the single-stranded molecule has the sequence 5 -(ATGC)10, then its double- stranded form could assume a Z-DNA structure. |
| B. | If the single-stranded molecule has the sequence 5 -(GATC)10, then its double-stranded form could assume an H-DNA structure. |
| C. | If the single-stranded molecule has the sequence 5 -(CTGA)10, then its double-stranded form could assume a hairpin structure. |
| D. | If the single-stranded molecule has the sequence 5 -(TGAC)10, then its double-stranded form could assume a cruciform structure. |
| Answer» B. If the single-stranded molecule has the sequence 5 -(GATC)10, then its double-stranded form could assume an H-DNA structure. | |
| 65. |
Which is a general property of both nucleosides and nucleotides? |
| A. | Both contain a pentose in the form of a furanose. |
| B. | Both contain at least one 5 -phosphate group |
| C. | Both contain a nitrogenous base that forms covalent H-bonds. |
| D. | Both contain a hemiacetal or hemiketal bond. |
| Answer» B. Both contain at least one 5 -phosphate group | |
| 66. |
Which characteristic is found in both purines and pyrimidines? |
| A. | They both have aromatic rings that undergo substantial tautomerization at neutral pH. |
| B. | They both are weak bases that can be positively charged at neutral pH. |
| C. | They both have multiple pKa values that result in zwitterion forms. |
| D. | They both can form stable N-glycosidic bonds with D-ribofuranose. |
| Answer» E. | |
| 67. |
Which component is found in both guanosine and uridine? |
| A. | Both contain an aldohexose. |
| B. | Both contain three hydroxyl groups. |
| C. | Both contain a 1 ,9 - bond. |
| D. | Both contain a pyranose. |
| Answer» C. Both contain a 1 ,9 - bond. | |
| 68. |
Which property is shared by both CTP and dTDP? |
| A. | Both contain the same sugar. |
| B. | Both contain the same charge at cellular pH. |
| C. | Both contain a planar six-membered ring. |
| D. | Both contain phosphodiester bonds. |
| Answer» D. Both contain phosphodiester bonds. | |
| 69. |
Which property is found in nucleosides and nucleotides? |
| A. | Both contain a nitrogenous base, a pentose, and at least one phosphate group. |
| B. | Both contain a covalent phosphodister bond that is broken in strong acid |
| C. | Both contain an anomeric carbon atom that is part of a -N-glycosidic bond. |
| D. | Both contain an aldose with hydroxyl groups that can tautomerize |
| Answer» D. Both contain an aldose with hydroxyl groups that can tautomerize | |
| 70. |
Which characteristic is shared by both adenine and cytosine? |
| A. | Both contain one methyl group. |
| B. | Both are anomeric. |
| C. | Both contain one keto group. |
| D. | Both are heterocyclic. |
| Answer» E. | |
| 71. |
Which characteristic is shared by purines and pyrimidines? |
| A. | Both contain two heterocyclic rings with aromatic character. |
| B. | Both can form multiple non-covalent hydrogen bonds |
| C. | Both exist in planar configurations with a hemiacetal linkage. |
| D. | Both exist as neutral zwitterions under cellular conditions. |
| Answer» C. Both exist in planar configurations with a hemiacetal linkage. | |
| 72. |
Which property is shared by both GDP and AMP? |
| A. | Both contain the same charge at neutral pH. |
| B. | Both contain the same number of phosphate groups. |
| C. | Both contain the same purine |
| D. | Both contain the same furanose. |
| Answer» E. | |
| 73. |
Which structural feature is found in the single-stranded DNA molecule? |
| A. | It can have a negatively-charged backbone composed of nitrogenous bases. |
| B. | Each 3 ,5 -phosphodiester bond will contain one phosphate group linking two deoxyribose sugars |
| C. | It can have one end with a 5 -phosphate group while the other end has a 2 -hydroxyl group. |
| D. | Each purine and pyrimidine will be paired with a complementary base. |
| Answer» C. It can have one end with a 5 -phosphate group while the other end has a 2 -hydroxyl group. | |
| 74. |
Which component is found in both adenosine and deoxycytidine? |
| A. | Both contain a pyranose. |
| B. | Both contain a 1,1 -N-glycosidic bond. |
| C. | Both contain a pyrimidine. |
| D. | Both contain a 3 -OH group |
| Answer» E. | |
| 75. |
Which describes the structural properties of a eukaryotic chromosome? |
| A. | It contains a double-helix composed of nucleosomes each with four million base-pairs. |
| B. | It is one double-stranded linear DNA molecule bound to proteins for compaction. |
| C. | It is arranged into a 30 nm fiber which is attached to the cell membrane. |
| D. | It contains linker regions which are arranged into loops and coiled to form a helix |
| Answer» C. It is arranged into a 30 nm fiber which is attached to the cell membrane. | |
| 76. |
Which are characteristics of bacterial genetic material? |
| A. | It is double-stranded and supercoiled. |
| B. | It is single-stranded and relaxed. |
| C. | It is circular and compacted into palindromes. |
| D. | It is linear and attached to a protein scaffold. |
| Answer» B. It is single-stranded and relaxed. | |
| 77. |
A new virus, virus X, is isolated and studied. Which molecule is most likely to be the genetic material of virus X? |
| A. | a linear DNA molecule containing 10,000 base-pairs |
| B. | a linear RNA molecule containing plasmids |
| C. | a circular DNA molecule containing nucleosomes |
| D. | a circular RNA molecule with a molecular weight of 10 billion |
| Answer» B. a linear RNA molecule containing plasmids | |
| 78. |
Assume that DNA molecules are studied in a variety of organisms and found to have the following properties. Which property would be consistent with the hypothesis that genetic material is composed of DNA? |
| A. | DNA in all organisms is composed of the same nucleotides. |
| B. | DNA in an organism remains constant as the organism ages. |
| C. | DNA from two different organisms has the same base composition. |
| D. | DNA is different in two different cells of the same organism. |
| Answer» C. DNA from two different organisms has the same base composition. | |
| 79. |
Which characteristic will be shared when comparing the single 5 -(GA)20-3 strand to another single-stranded DNA molecule with the sequence 5 -(AT)20-3 ? |
| A. | Both contain a palindromic sequence. |
| B. | Both can form the same secondary structures. |
| C. | Both could hybridize to the same RNA molecule. |
| D. | Both will have the same overall charge. |
| Answer» E. | |