Structure of dsDNA Quiz | Structure of dsDNA Multiple Choice Questions(MCQs) & Answers

1 Which of them is used to introduce negative supercoiling in DNA?
A Type 1 topoisomerase
B Ethidium bromide
C Gyrase/ type 2 topoisomerase
D SYBR gold

Answer: Gyrase/ type 2 topoisomerase
2 What is the term given to the supercoiling of circular DNA?
A Twist number
B Linking number
C Writhe number
D Cross-linking

Answer: Linking number
3 Which of this factor is not responsible for thermal denaturation of DNA?
B Temperature
C Ionic strength
D Humidity

Answer: Humidity
4 The stability and formation of G-quadruplex depends on __________
A Monovalent cation
B Divalent cation
C Bivalent cation
D Pentavalent ion

Answer: Monovalent cation
5 Name the nitrogenous base which is found in abundance in G-quadruplex?
A Adenine
B Guanine
C Cytosine
D Thymine

Answer: Guanine
6 The third strand of triple helix is paired in which scheme?
A Hoogsteen base pair scheme
B Intermolecular base pair scheme
C Intramolecular base pair scheme
D G-quartet scheme

Answer: Hoogsteen base pair scheme
7 Which one of the following statement is INCORRECT for Z-DNA?
A Left-handed DNA
B Mostly found in alternating purine-pyrimidine sequences
C Only one deep, narrow groove
D Anti glycosidic bond conformation

Answer: Anti glycosidic bond conformation
8 How many base pairs are there in every helical turn of Watson-Crick double helix model?
A 32.3
B 11.6
C 20
D 10.4

Answer: 10.4
9 Which form of DNA is described by Watson-Crick model?
D Quadraplex DNA

Answer: B-DNA
10 Who described the structure of DNA double helix?
A Peter Mitchell
B Andre Jagendorf
C Ernest Uribe
D Watson and Crick

Answer: Watson and Crick
11 Levene investigated and found that the nucleic acid is composed of poly-nucleotides and each nucleotide is composed of one base, a sugar molecule and a phosphate. This was performed on the genome of________________
A Bacteria
B Fungi
D Yeast

Answer: Yeast
12 In the late 1970s non double helical form of DNA was also suggested but was discarded on the basis of certain factors. Which of the following is not a factor responsible?
A X-ray crystallography
B Nuclein
C Topoisomerase
D Nucleosome core particle

Answer: Nuclein
13 With respect to the importance of hydrogen bonding and DNA double helix stability, which of the following statements is false?
A Favorable tautomeric form of nucleotide bases
B Contributes to the thermodynamic stability
C Decreases the entropy
D Specificity of base pairing

Answer: Decreases the entropy
14 In a DNA double helix the bases are held together by hydrogen bonds. These hydrogen bonds are _________
A Covalent bonds
B Non-covalent bonds
C Ionic bonds
D Van der Waals forces

Answer: Non-covalent bonds
15 The hydrogen bonds formed during A and T bonding occurs between C6NH2 of A and _____
A C4O of T
B PO3–
C C6O of A
D C1O of T

Answer: C4O of T
16 What should be the complementary strand of 3’….ATGGCTTGA….5’?

Answer: 5’….TACCGAACT….3’
17 In 1952, an unambiguous established work in the laboratory of Alexander Todd led to the discovery of _____________
A Chemical nature of DNA
B X-ray diffraction structure of DNA
C 3’-5’ phosphodiester linkage regularly links the nucleotides of DNA
D Nucleic acid strands are held together by hydrogen bonds

Answer: 3’-5’ phosphodiester linkage regularly links the nucleotides of DNA
18 In early 1950s high quality X-ray diffraction photographs of DNA suggesting the DNA being double helix and composed of two nucleotide strands. Who took those photographs?
A Rosalind Franklin
B William Asbury
C Francis H. Crick and James D. Watson
D Rosalind Franklin and Maurice Wilkins

Answer: Rosalind Franklin and Maurice Wilkins
19 The first X-ray diffraction patterns of DNA were taken in 1938 by ___________
A William Asbury
B Rosalind Franklin
C Francis H. Crick
D Linus Pauling

Answer: William Asbury
20 A nucleoside is composed of
A a base+ a sugar
B a base+ a sugar+ phosphate
C a base+ a phosphate
D none of these

Answer: a base+ a sugar

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