Nucleic Acid Multiple Choice Questions and Answers

1 Identify the purine base of nucleic acids in the following

A Cytosine

B Thymine

C Uracil

D Adenine

View Answer

Answer: Adenine

2 Which of the following statements is true?

A Sugar component of a nucleotide is ribose

B Sugar component of a nucleotide is deoxyribose

C The bases in nucleotides are attached to a pentose sugar moiety by a glycosidic linkage

D The sugar molecule of the nucleotide is in L-configuration

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Answer: The bases in nucleotides are attached to a pentose sugar moiety by a glycosidic linkage

3 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

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Answer: a base + a sugar

4 The sugar molecule in a nucleotide is

A Pentose

B Hexose

C Tetrose

D Triose

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Answer: Pentose

5 Arrangement of nucleotides in DNA can be seen by

A Ultracentrifuge

B X-Ray crystallography

C Light microscope

D Electron microscope

View Answer

Answer: X-Ray crystallography

6 One of the following nucleic acids has a left handed helix

A M-RNA

B T-RNA

C A-DNA

D Z-DNA

View Answer

Answer: Z-DNA

7 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

View Answer

Answer: It has alternating GC sequences

8 Which of the following statements is true?

A The template strand matches the sequence of the RNA transcript

B The two strands of DNA run parallel to each other

C G-C bonds are much more resistant to denaturation than A-T rich regions

D The common form of DNA is left handed

View Answer

Answer: G-C bonds are much more resistant to denaturation than A-T rich regions

9 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

View Answer

Answer: Both contain two keto groups

10 Histones

A are negatively-charged globular proteins

B contain both α-helix and β-pleated sheet

C have molecular weights in excess of 100,000

D contain high amounts of basic amino acids

View Answer

Answer: contain high amounts of basic amino acids

11 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

View Answer

Answer: Both can be double-stranded, circular DNA

12 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

View Answer

Answer: It is double-stranded and supercoiled

13 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

View Answer

Answer: DNA in an organism remains constant as the organism ages

14 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

View Answer

Answer: a linear DNA molecule containing 10,000 base-pairs

15 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

View Answer

Answer: It is one double-stranded linear DNA molecule bound to proteins for compaction

16 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

View Answer

Answer: The viral components labeled with 32P remain outside the cell during a successful infection

17 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

View Answer

Answer: Eukaryotic genetic material is compacted by wrapping the double-helix around histone proteins to form nucleosomes

18 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 α-helix

D They are globular proteins with a positive charge

View Answer

Answer: They are globular proteins with a positive charge

19 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

View Answer

Answer: Both will have the same overall charge

20 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

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