Topic 1 DNA structure

Question 1

Adenine + Thymine comprise of how much of DNA (%)

Answer 1

30% each

Question 2

Pyrimidines

Answer 2

C + T

Question 3

DNA sugar

Answer 3

Deoxyribose

Question 4

Phosphodiester bonds found on which part of DNA

Answer 4

Adjacent deoxyribose sugars

Question 5

DNA topoisomerase

Answer 5

Alters supercoiled structure of DNA

DNA can be accesible by other enzymes for DNA replication

Question 6

DNA polymerase 3

Answer 6

complementary base pair bonding

Question 7

DNA polymerase 1

Answer 7

replaces RNA primers with DNA

Question 8

Exonuclease

Answer 8

Removes RNA primers

Question 9

How is proof reading done

Answer 9

DNA polymerases

3’ to 5’ direction

Question 10

How often do mistakes occur after proof reading

Answer 10

1 in 10^9

Question 11

Name the 4 repair mechanisms proteins

Answer 11

Base excision Repair Protein

Nucleotide excision repair protein

DNA polymerase 1

Uracil N-Glycosylase

Question 12

How does Base excision repair proteins work?

Answer 12

Cut out damaged bases

Question 13

How does nucleotide exicision repair proteins work?

Answer 13

Cut out damaged DNA strands

Question 14

how does DNA polymerase 1 repair

Answer 14

Replaces DNA with correct bases

Question 15

How does N-glycosylase repair

Answer 15

Recognises uracil and cuts it out

Question 16

How many bonds does C-G have

Answer 16

3H

Question 17

What is the purpose of Single stranded binding proteins

Answer 17

Bind to DNA –> stabilise ssDNA

Question 18

How is a polypeptide chain terminated

Answer 18

stop codon + release factor

Question 19

How is a polypeptide chain cleaved

Answer 19

Release factor hydrolyses bond between P site and last amino acid

Question 20

Where does a wobble base pairing occur generally

Answer 20

1st site of ribosome

Question 21

Which enzyme adds AA to tRNA

Answer 21

aminoacyl -tRNA synthase

Question 22

Wha is adde during capping

Answer 22

7 methyl guanosine PPP