The Structure And Replication Of DNA 1.2

Question 1

What are the individual units of DNA called

Answer 1

Nucleotides

Question 2

What does a nucleotide contain

Answer 2

Phosphate
Deoxyribose sugar
A base (A,T,C or G)

Question 3

What are the four bases (full names)

Answer 3

Thymine
Adenine
Cytosine
Guanine

Question 4

What are the bases on each strand held together by

Answer 4

Weak hydrogen bonds

Question 5

What is the bade pairing rule

Answer 5

The bases are complementary to one another
A-T and C-G

Question 6

How many carbons is a deoxyribose sugar made up of

Answer 6

5

Question 7

What carbon is the phosphate connected to

Answer 7

5’ carbon (5 prime carbon)

Question 8

What are nucleotides held together by

Answer 8

Strong covalent bonds

Question 9

DNA molecules are made up if two strands lying side by side, running in opposite directions what does that make the strands

Answer 9

Antiparallel

Question 10

As the strands run in opposite directions what is each strand known as

Answer 10

One is 5’ to 3’ and the other is 3’ to 5’

Question 11

What is DNA replicated by before cell division

Answer 11

DNA polymerase (enzyme)

Question 12

Stage one of DNA replication

Answer 12

DNA double helix is unwound and unzipped, hydrogen bonds between bases are broken apart

Question 13

What is stage two of DNA replication

Answer 13

• DNA polymerase needs primers to start replication. A primer is a short strand of nucleotides which binds to the 3’ end of the template DNA strand allowing polymerase to add DNA nucleotides
• DNA polymerase adds the free DNA nucleotides to the 3’ end of the primer. DNA polymerase works in a 3’ to 5’ direction.

Question 14

Why is the leading strand continuous and the lagging strand isnt

Answer 14

The lagging strand is replicated in fragments because nucleotides can’t be added to the phosphate (5’) end because DNA polymerase can only add DNA nucleotides in a 3’ to 5’ direction

Question 15

What is stage three of DNA replication

Answer 15

The fragments are then sealed together by an enzyme called ligase

Question 16

What are the 5 things required for DNA replication

Answer 16

DNA
Primers
Free nucleotides
DNA polymerase
Ligase

Question 17

What are the 5 things required for DNA replication

Answer 17

DNA
Primers
Free nucleotides
DNA polymerase
Ligase

Question 18

What is polymerase chain reaction (PCR)

Answer 18

Polymerase chain reaction is a technique for the amplification of DNA

Question 19

What does amplification of DNA mean

Answer 19

Increasing the amount of the DNA

Question 20

What does PCR allow scientists to do easily

Answer 20

Turn a specific sequence of DNA into millions if copies which can then be used for analysis

Question 21

What must DNA polymerase must with stand

Answer 21

High temperatures

Question 22

What are the three stages of PCR

Answer 22

Denaturation
Annealing
Elongation/extension

Question 23

What is denaturation

Answer 23

DNA is heated ti between 92-98 degrees which separates original DNA strands by breaking hydrogen bonds between strands

Question 24

What is annealing

Answer 24

DNA is then cooled to between 50 - 60 degrees to allow primers to bind to the target sequence

Question 25

What is elongation/extension

Answer 25

It is then heated to between 70 and 80 degrees for heat tolerant DNA polymerase to replicate the region of DNA

Question 26

Three things that PCR amplifies DNA for

Answer 26

Solving crimes (forensics)
Diagnosing genetic disorders
Paternity test