Structure and replication of DNA

Question 1

Describe the structure of a DNA nucleotide

Answer 1

Deoxyribose sugar
Phosphate
Base

Question 2

State the DNA base pairing rule

Answer 2

Adenine to Thymine
Guanime to Cytosine.

Question 3

What bonds are between the bases

Answer 3

Weak hydrogen bonds.

Question 4

Where is the Phosphate on the nucleotide

Answer 4

on the 5 Prime end.

Question 5

What does the base sequence of DNA form

Answer 5

The base sequence of DNA forms the
genetic code

Question 6

What happens before cell division

Answer 6

DNA replication

Question 7

Describe the 6 stages of DNA replication

Answer 7

1.DNA is unwound and hydrogen bonds between bases are broken to form two template strands.

2.DNA polymerase needs primers to start replication.

3.A primer is a short strand of nucleotides which binds to the 3’ end of the template DNA strand allowing DNA polymerase to add DNA nucleotides.

4.DNA polymerase adds DNA nucleotides using complementary base pairing to the 3 end of the new DNA strand which is forming.

5.DNA polymerase can only add DNA nucleotides in one direction resulting in the leading strand being replicated continuously and the lagging strand replicated in fragments.

6.Fragments of DNA on the lagging strand are joined together by ligase.

Question 8

What is PCR?

Answer 8

The amplification of DNA

Question 9

What does PCR stand for?

Answer 9

Polymerase Chain Reaction

Question 10

Describe the 3 Stages of PCR

Answer 10

1. DNA is heated to between 92 and 98°C to
   separate the strands.
2. It is then cooled to between 50 and 65°C to
   allow primers to bind to target sequences.
3. It is then heated to between 70 and 80°C for
   heat-tolerant DNA polymerase to replicate
   the region of DNA

Question 11

State the Practical applications of PCR

Answer 11

1. help solve crimes,
2. settle paternity suits
3. diagnose genetic disorders.