Molecular Basis Of Inheritance Question 191
Question: Choose the sequence in which the following enzymes take part in DNA replication.
(i) Helicase
(ii) Primase
(iii) SSB
(iv) DNA polymerase
(v) DNA ligase
Options:
A) (i) $ \to $ (v) $ \to $ (iv) $ \to $ (iii) $ \to $ (ii)
B) (i) $ \to $ (ii) $ \to $ (iii) $ \to $ (iv) $ \to $ (v)
C) (i) $ \to $ (iii) $ \to $ (ii) $ \to $ (iv) $ \to $ (v)
D) (i) $ \to $ (iv) $ \to $ (iii) $ \to $ (ii) $ \to $ (v)
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Answer:
Correct Answer: C
Solution:
[c] Steps of DNA Replication in the initiation step, several key factors are recruited to an origin of replication.
This origin of replication in unwound and the partially unwound strands form a ‘replication bubble’, with one replication fork on either end.
Each group of enzymes at the replication fork moves away from the origin, unwinding and replicating the original DNA as they proceed.
The factors involved are collectively called the pre-replication complex.
It consists of the following A helicase, which unwinds and splits the DNA ahead of the fork.
Thereafter, Single-strand Binding Proteins (SSB) swifty bind to the separated DNA, thus preventing the strands from reunting.
A primase, which generates an RNA primer to be used in DNA replication.