Structure and Replication of DNA

Question 1

State the name for a DNA subunit

Answer 1

DNA nucleotide

Question 2

Name the basic components of a
DNA nucleotide

Answer 2

Deoxyribose sugar, phosphate and
a base

Question 3

Which bases are found in a
molecule of DNA?

Answer 3

ATGC

Question 4

How are nucleotides in a DNA
strand held together?

Answer 4

By hydrogen bonds between
complementary bases

Question 5

Describe complimentary base pairing
in DNA

Answer 5

Adenine pairs with Thymine
Cytosine pairs with Guanine

Question 6

Describe how the two DNA strands
are held together

Answer 6

By hydrogen bonds between
complementary bases

Question 7

How can the two strands in DNA be
described in terms of their structure?

Answer 7

Antiparallel structures twist to
form a double helix

Question 8

Name the nucleotide structure found
at the 3’ end of a DNA strand

Answer 8

Deoxyribose sugar

Question 9

Name the nucleotide structure
found at the 5’ end of a DNA strand

Answer 9

Phosphate

Question 10

Prior to cell division, what
happens?

Answer 10

DNA is replicated

Question 11

What must be done to a molecule of
DNA to allow DNA replication to
begin?

Answer 11

DNA is unwound and hydrogen
bonds break to form two template
strands

Question 12

Name the enzyme involved in
adding nucleotides to the new DNA
strand during replication

Answer 12

DNA polymerase

Question 13

How does DNA polymerase add
nucleotides to a new DNA strand
forming?

Answer 13

To the 3’ (deoxyribose) end of
the new strand forming

Question 14

Which additional structures are
required for DNA polymerase to
begin DNA replication?

Answer 14

Primers

Question 15

Describe how the leading DNA strand
is replicated

Answer 15

continuously

Question 16

What is the name given to the DNA
strand that is replicated in
fragments?

Answer 16

The Lagging strand

Question 17

How are the fragments in the lagging
strand of DNA joined together?

Answer 17

By the enzyme DNA ligase

Question 18

Name the technique used to
amplify DNA

Answer 18

Polymerase Chain reaction (PCR)

Question 19

What are primers in PCR?

Answer 19

Short strands of nucleotides which
are complementary to specific
target sequences

Question 20

What is the function of a primer in
PCR?

Answer 20

Bind to specific target sequences at
the two ends of the DNA to be
amplified

Question 21

DNA is heated to this temperature
to separate the strands

Answer 21

92-98 °C

Question 22

Why is DNA cooled to between
50°C and 65°C during PCR?

Answer 22

To allow primers to bind to target
sequences

Question 23

Why is the DNA heated to between
70°C and 80°C after the primers
bind in PCR?

Answer 23

For heat tolerant DNA
polymerase to replicate the
region of DNA

Question 24

Give examples of why PCR would be
used to amplify samples of DNA

Answer 24

To help solve crimes, paternity
suits and diagnose genetic
disorders