DNA

Question 1

What is the role/purpose of DNA?

Answer 1

Carry inheritable genetic code which controls cell activities and protein synthesis

Question 2

What is DNA made up of?

Answer 2

Nucleotides that contain:

• sugar (deoxyribose) and phosphate backbone
• nitrogenous bases (adenine, thymine, guanine and cytosine)

5’ end - free phosphate group
3’ end - free OH (hydroxy) group

Bonds

• covalent bonding within a strand of DNA (strong)
• hydrogen bonding between the complementary base pairs (weak)

Question 3

How do the bases pair?

Answer 3

complementary base pairing in antiparallel direction

A-T, G-C

Question 4

What are A and G known as?

Answer 4

Purines

Question 5

What are T and C known as?

Answer 5

Pyrimidines

Question 6

Differentiate between mitosis and meiosis.

Answer 6

Mitosis produces two identical cells with 46 chromosomes and is used for growth and repair

Meiosis produces 4 unique cells with 23 chromosomes and is used for genetic variation and sex cells. The crossing over mixes the genetic information.

Question 7

What is helicase?

Answer 7

Group of enzymes that work in breaking hydrogen bonds to begin cell replication. It is involved in the ‘unzipping’ of DNA strands.

Question 8

How do DNA strands ‘unzip’?

Answer 8

From the 3’ to 5’ (leading strand)
Fragments are then added from the 5’ to 3’ (lagging strand) in a process of elongation in replication
It also occurs in different places (no starting point)

Question 9

Differentiate between DNA and RNA

Answer 9

DNA stores genetic code and RNA copies that code for specific purposes