DNA

Question 1

Which 2 people discovered that DNA contained genetic info not proteins?

Answer 1

Hershey and Chase

Question 2

What type of bonds exist between adjacent deoxyribose sugars?

Answer 2

Phosphodiester bonds

Question 3

How many hydrogen bonds exits between A and T?

Answer 3

2

Question 4

How many hydrogen bonds exits between C and G?

Answer 4

3

Question 5

Meselson Stahl experiment:

After 3 generations what percentage of N15 would exist?

Answer 5

12.5%

Question 6

Is DNA replication conservative or semi conservative?

Answer 6

Semi conservative

Question 7

What is semi conservative replication?

Answer 7

Half original DNA

Half new DNA

Question 8

What is the function of DNA helicases?

Answer 8

Unwind DNA strand

Question 9

What is the result of proteins binding to the strands?

Answer 9

Stabilises denatured DNA

Question 10

What is the function of DNA primase?

Answer 10

Synthesises short RNA primer to allow replication to commence

Question 11

Which DNA polymerase elongates new DNA by initiating complementary base pairing?

Answer 11

DNA polymerase I

Question 12

Which DNA polymerase carries out replication in prokaryotes?

Answer 12

DNA polymerase III

Question 13

At which end of DNA is the free OH group?

Answer 13

3’ end

Question 14

Which direction is DNA synthesis?

Answer 14

5’ to 3’

Question 15

Which DNA polymerase is involved with replication?

Answer 15

DNA polymerase I

Question 16

What is the rate of errors in DNA synthesis?

Answer 16

1 in 10^5

Question 17

After 3’ to 5’ editing function what is the new error frequency?

Answer 17

1 in 10^7

Question 18

After all enzyme checks what is error frequency?

Answer 18

1 in 10^9

Question 19

What adduct is formed from ethyl methane sulphonate (EMS)?

Answer 19

O6-ethylguanine adduct

Question 20

What does this adduct mispair with during replication?

Answer 20

Thymine

Question 21

What are the 2 types of mutations?

Answer 21

Germ cell

Somatic

Question 22

Which type of mutation can be inherited?

Answer 22

Germ cell

Question 23

Which mutation may lead to cancer?

Answer 23

Somatic

Question 24

What are the 3 repair proteins?

Answer 24

DNA repair proteins
Base excision repair proteins
Nucleotide excision repair proteins

Question 25

Give an example of a nucleotide excision repair protein and its role.

Answer 25

``` uracil-N-glycosylase: spontaneous deamination (removal of NH3) from cytosine to form uracil --> uracil-N-glycosylase cuts out uracil ```

Question 26

Does the human genome contain coding or non-coding genetic information?

Answer 26

Both

Question 27

Sanger DNA sequencing: | Which end of the primer are dNTPs with complementary bases added to?

Answer 27

3'OH end

Question 28

Do ddNTPs have a 3'OH end? | What happens when ddNTPs occupy the 3' position?

Answer 28

No | Termination of synthesis leading to DNA denaturing

Question 29

What method differentiates fragments of DNA by length? | Which DNA fragments run further?

Answer 29

Gel electropheresis | Shorter

Question 30

What is a polymorphism?

Answer 30

Mutation affecting at least 1% population

Question 31

Which of the following is NOT a use of microarray: - comparing polymorphisms between individuals - comparing gene expression between different cell types - comparing genetic inheritence between individuals - comparing gene expression between normal and diseased tissue

Answer 31

Comparing genetic inheritence between individuals

Question 32

What is epigenetics?

Answer 32

The control of gene expression by methods other than genetic variation

Question 33

Which part of a cell does transcription mostly take place in?

Answer 33

Nucleus

Question 34

How many base pairs upstream is the TATA box?

Answer 34

25

Question 35

Which enzyme binds transcription factor to genes to initiate mRNA transcription?

Answer 35

RNA polymerase II

Question 36

In which direction does RNA synthesis take place?

Answer 36

5' to 3'

Question 37

Which type of bonds are formed when RNA polymerase joins nucleotides together?

Answer 37

Phosphodiester

Question 38

mRNA codes for how many proteins in prokaryotes?

Answer 38

more than one

Question 39

mRNA codes for how many proteins in eukaryotes?

Answer 39

one

Question 40

Which end is the polyA tail added to in mRNA? | What is an exception to this?

Answer 40

3' end | Histone

Question 41

What does the splice site at 5' end contain?

Answer 41

GU

Question 42

What does the splice site at 3' end contain?

Answer 42

AG

Question 43

What enzyme responsible for charging tRNA with an amino acid at its 3' end?

Answer 43

aminoacyl tRNA synthetase

Question 44

What is the start codon?

Answer 44

AUG

Question 45

What does the start codon carry in: 1) eukaryotes? 2) prokaryotes?

Answer 45

1) Methionine | 2) N-formylmethionine

Question 46

What is an mRNA with multiple ribosomes called?

Answer 46

Polysome

Question 47

What is the site order tRNA takes during protein synthesis?

Answer 47

Arrive (A) Park (P) Exit (E)

Question 48

During protein synthesis involving tRNA which chain is transferred to the new amino acyl tRNA at the A site?

Answer 48

Peptidyl chain

Question 49

Name 3 stop codons

Answer 49

UAA UGA UAG

Question 50

What is prenylation?

Answer 50

Addition of hydrophobic group

Question 51

What process do the following 3 antibiotics intefer with? Tetracycline Streptomycin Chloramphenico

Answer 51

Bacterial protein synthesis