Week 4

Question 1

Name the nucleotide structure

Answer 1

sugar phosphate + Base

Question 2

DNA function

Answer 2

Encodes info in the sequence of base pairs in the DNA strand,

Question 3

What is DNA always found in?

Answer 3

A double helix

Question 4

Strands of DNA are

Answer 4

Linear strands

Question 5

Base pair ruling is…

Answer 5

A=T G=C

Question 6

A single strand of a helix can act as a template for…

Answer 6

Making a complimentary second strand

Question 7

Semiconservative replication def

Answer 7

If both strands of a helix act as templates,

two identical daughter duplexes can be produced

Question 8

Newly synthesised strands have…

Answer 8

Opposite polarity

Question 9

What are Okasaki fragments

Answer 9

Small pieces which are joined up of DNA

Question 10

What enzyme is responsible for making new DNA strands?

Answer 10

DNA polymerase

Question 11

What are the cause of symptoms in SCID?

Answer 11

Lack of DNA synthesis

Question 12

Xeroderma Pigmentosum

Answer 12

Multiple skin cancers

Question 13

DNA strand synthesised continuously is called the

Answer 13

Leading strand

Question 14

DNA strand synthesised discontinuously is called the

Answer 14

Lagging strand

Question 15

RNA function

Answer 15

Assistance in DNA replication

Question 16

Helicase function

Answer 16

Opens the double helix, unwounds

Question 17

Single stranded binding proteins

Answer 17

prevents the double helix reforming

Question 18

Clamp

Answer 18

Holds DNA polymerase onto the DNA

Question 19

Ligase function

Answer 19

Links Okasaki fragments

Question 20

Mutation

Answer 20

Change of sequence of base pairs in the DNA

Question 21

Germ cells function + mutation

Answer 21

Required for reproduction; mutation leads to inherited diseases

Question 22

Somatic cells function + mutation:

Answer 22

All other cells in the body; mutation leads to cancer

Question 23

Germ cell mutation symptoms

Answer 23

Loss of protein function, all carriers children will have it

Question 24

Deamination

Answer 24

Loss of amino group from the cystine

Question 25

Depurination

Answer 25

Loss of a base pair

Question 26

Thymine dimers

Answer 26

Results from cross linking two adjacent thymines by UV light

Question 27

Name the DNA repair steps

Answer 27

1. Rec + Rem of DNA cells
2. Filling of missing DNA by a polymerase
3. Ligation of new DNA to existing DNA

Question 28

Name the standard removal systems of DNA repair

Answer 28

Mismatch repair, excision repair, double strand break repair

Question 29

Describe mismatch repair

Answer 29

A distortion caused by the mismatch is recognised by mismatch repair proteins.

A long section of DNA is removed and then resynthesized by a proof-reading

polymerase

Question 30

Nucleotide excision repair

Answer 30

A damaged nucleotide is recognised by a different set of proteins. The base is excised, often producing a small gap, which is filled as before