DNA & Genomics I

Question 1

What are the components of a nucleotide?

Answer 1

Phosphate group, 5-carbon sugar (Pentose sugar), Nitrogenous base

Question 2

What are the components of a nucleoside?

Answer 2

Composed of a 5-carbon sugar and nitrogenous base

Question 3

What are the bond(s) between nucleotides?

Answer 3

Phosphodiester bonds

Question 4

What are the pyrimidines

Answer 4

Cytosine, Uracil and Thymine

Question 5

What are the purines

Answer 5

Adenine and Guanine

Question 6

State the mechanism of DNA replication

Answer 6

Semi-conservative DNA replication

Question 7

What are the enzymes involved in the synthesis of new DNA strands

Answer 7

Primase, Helicase, Topoisomerase, DNA polymerase, DNA ligase

Question 8

State the role of DNA ligase in DNA replication

Answer 8

It seals the nick between DNA fragments by forming phosphodiester bond

Question 9

State the role of helicase in DNA replication

Answer 9

It unzips the double helix of DNA strand

Question 10

State the role of topoisomerase in DNA replication

Answer 10

It breaks, swivels and rejoins DNA strands

Question 11

What does RNA primer provide DNA polymerase?

Answer 11

free 3’ OH end

Question 12

Which direction does DNA polymerase add DNA nucleotides

Answer 12

5’ to 3’ direction, DNA nucleotides added to 3’ OH end of growing strand

Question 13

Why is DNA a suitable store of information?

Answer 13

It can be replicated accurately.
It is a stable molecule
It is a backup of the code as there is 2 strands in a DNA molecule
Coded information can be easily accessed and readily utilised

Question 14

How is the lagging strand synthesized?

Answer 14

Lagging strand is synthesized discontinuously in fragments known as Okazaki fragments, each fragment synthesized by RNA primer.