DNA

Question 1

what’s the central dogma

Answer 1

process of transcription then translation of DNA to RNA to proteins

Question 2

components of a nucleotide

Answer 2

phosphate + a nucleoside (base + sugar)

Question 3

components of a nucleoside

Answer 3

base + sugar

Question 4

sugar in DNA + RNA + difference

Answer 4

RNA = ribose
DNA = deoxyribose
on carbon 3 DNA nucleotide only has H, RNA has hydroxyl

Question 5

2 types of bases

Answer 5

purines and pyrimidines

Question 6

features of purines + examples

Answer 6

• larger than pyrimidines

e. g. adenine + guanine

Question 7

features pyrimidines + examples

Answer 7

• smaller than purines

e. g. thymine, uracil + cytosine

Question 8

nucleoside name of each base

Answer 8

adenine - adenosine
guanine - guanosine 
thymine - thymidine
uracil - uridine 
cytosine - cytosine

Question 9

4 DNA nucleotides

Answer 9

dATP, dCTP, dTTP, dGTP - deoxy guanine triphosphate

Question 10

4 RNA nucleotides

Answer 10

ATP,CTP, UTP, GTP - guanine triphosphate

Question 11

type of bond between nucleotides + bonding elements

Answer 11

phosphodiester bond between phosphate of carbon 5 and hydroxyl of carbon 3

Question 12

nucleotide rules for polymerisation

Answer 12

can only add to free 3 prime end

Question 13

features of DNA

Answer 13

sugar phosphate backbone, antiparallel strands, bonds hydrogen bonds between bases

Question 14

two strands + direction

Answer 14

leading 3’ prime - 5’ prime

lagging 5’ - 3’

Question 15

DNA polymerase addition of nucleotides

Answer 15

only from 5’ to 3’ on DNA polymerase chain

-therefore continuous on leading

Question 16

features of DNA replication

Answer 16

• semiconservative
• RNA primers required to start
• catalysed by DNA polymerase
• begins at origin of replication
  (many origins of replication per chromosome to allow quick replication of DNA)

Question 17

enzyme that unwinds DNA - resulting structure

Answer 17

• helicase, creates replication bubble

Question 18

Replication of leading strand

Answer 18

• begins at RNA primer

- DNA polymerase continuously adds nucleotides

Question 19

replication of lagging strand

Answer 19

• occurs discontinuously

only add from 5’ to 3’ therefor Okazaki fragments produced

Question 20

DNA as tightly packed chromosome

Answer 20

heterochromatin

Question 21

DNA as loose packed chromosomes undergoing replication/ transcription

Answer 21

euchromatin

Question 22

number of bonds between adenosine and thymine in DNA

Answer 22

2 hydrogen bonds

Question 23

number of bonds between guanine and cytosine in DNA

Answer 23

3 hydrogen bonds

Question 24

DNA proof reading name + mechanism

Answer 24

exonuclease activity

- removes wrong nucleotides from 3 prime to 5 prime (opposite direction to replication)

Question 25

requirements for replication of DNA

Answer 25

helicase - unwind DNA (replication bubble)

RNA primer - DNA polymerase can’t bind by its self

Question 26

enzyme which synthesises RNA primer

Answer 26

primase