Question

1. Which of the following is / are TRUE regarding a DNA molecule?

	a)	A SINGLE DNA molecule consists of 2 nucleotide chains
	b)	Covalent, phosphodiester bonds connect the nucleotides of a single nucleotide chain together
	c)	Phosphodiester bonds join the separate nucleotide chains to one another forming a single molecule
	d)	Hydrogen bonds join the separate nucleotide chains to one another forming a single molecule

2.

During DNA replication, the enzyme helicase:

a)		Unwinds the double helix
b)		Functions at both ends of a replication bubble.
c)		Follows primase activity.
d)		none of the above is correc

3.

A dNTP building block consists of which of the following?

a)		deoxyribose
b)		ribose
c)		a sugar ring with 2' AND 3' OH groups
d)		a nitrogenous base
e)		a single phosphate group
f)		three phosphate groups

Answer 1

1. The true statements are a,b and d

A DNA molecule is composed of 2 polynucleotide chains connected with each other by hydrogen bonds.Between A and T there are 2 hydrogen bond and between G and C there are 3.

During polymerization when nucleotides are incorporated within the DNA a covalant phosphodiester bond is formed between 5'P of one nucleotide and 3'OH of the adjacent nucleotide.

2.Option a

Helicase usually binds to the dsDNA and unwinds it so that the 2 strands gets separated and replication can begin.

3.Option a,d and e

Each dNTP is composed of deoxyribose sugar,a phosphate group and a nitrogenous base.