Molecular Basis of Inheritance MCQs | Molecular Basis of Inheritance Objective Type Questions and Answers

Questions
1 Linking number is the sum of which geometric components?
A Twist and writhe
B Toroid and writhe
C Twist and wrap
D Twist and crossover

Answer:Twist and writhe
2 3 – dimension structure of cccDNA is ___________
A Nicked
B Supercoiled
C Flat
D Torsionally stressed

Answer: Torsionally stressed
3 Plectonomic writhe is __________
A Cylindrical axis winding
B Long axis twisted around itself
C Helical turns of one strand about the other
D Number of encounters of the two strands of a helix

Answer: Long axis twisted around itself
4 Interwound writhe and spiral writhe are topologically different.
A True
B False

Answer:False
5 Twist and writhe are interconvertible.
A True
B False

Answer: True
6 What is the relation between linking number (Lk), writing number (Wr) and twist number (Tw)?
A Lk = Tw – Wr
B Lk = Wr – Tw
C Tw = Lk – Wr
D Tw = Lk + Wr

Answer:Tw = Lk – Wr
7 How can we remove supercoils from cccDNA?
A Treat with DNase
B Treat with detergent
C Treat with endonuclease
D Application of heat

Answer: Treat with DNase
8 If Lk < Lk0 then DNA is ____________
A Relaxed
B Negatively coiled
C Positively coiled
D ΔLk > 0

Answer:Negatively coiled
9 What is ΔLk and Lk0 dependent upon?
A Histone concentration
B G : A ratio
C Composition of DNA
D Length of DNA

Answer:Length of DNA
10 Strand separation is easily accomplished in positively supercoiled DNA.
A True
B False

Answer:False
11 Which of the following organism has been found to have a positively supercoiled DNA?
A Saurida tumbil
B Monarda didyma
C Thermus aquaticus
D Cyanobacteria

Answer:Thermus aquaticus
12 Which of the following is not true about positive supercoils?
A Helps to avoid denaturing
B Over wounded DNA
C Strand separations require low energy
D Rare form of DNA supercoiling

Answer: Strand separations require low energy
13 Packaging of DNA around nucleosome is known as ____________
A Toroid writhes
B Twist
C Plectonemic writhes
D Supercoils

Answer: Toroid writhes
14 The nucleosome is seen to have negative supercoils.
A True
B False

Answer: True
15 Which of the following is known to relax supercoiled DNA?
A Nuclease
B DNase I
C Endonuclease
D Topoisomerase

Answer:Topoisomerase
16 With respect to topoisomerases which of the following is true?
A Only of one type
B Never changes linking number
C Requires ATP
D Introduces knots

Answer:Requires ATP
17 Topoisomerases I and II differ only on the number of steps required to change the linking number.
A True
B False

Answer:False
18 Which special enzyme introduces negative supercoils in DNA?
A Type I topoisomerase
B Type II topoisomerase
C Gyrase
D Helicase

Answer:Gyrase
19 Which of the following is not a property of topoisomerase?
A Removal of supercoil
B Helps in DNA replication
C Cannot catenate and decatenate
D Utilizes ATP to change linking number

Answer: Cannot catenate and decatenate
20 Topoisomerases introduces catenation to promote cell division.
A True
B False

Answer: False
junior administrative assistant jaa test series