DNA synthesis and replication

Question 1

Mitosis

Answer 1

how our cell replicates its DNA

Question 2

Semi-conservative

Answer 2

each DNA strand is used as a template strand for the synthesis of 2 new strands. one strand is the parent strand and one is the newly synthesised strand.

Question 3

Prokaryotic replication

Answer 3

single circular chromosome
bidirectional
single origin of replication

Question 4

leading strand

Answer 4

continuously synthesised in it 5-3 prime direction

Question 5

lagging strand

Answer 5

discontinuously synthesised in its 5-3 direction as okazakis fragments

Question 6

DNA polymerase III

potato

Answer 6

Progressive addition of new nucleotides A,T,C,G

extends on from the primer

Question 7

Primaze

prune

Answer 7

enzyme that makes the RNA primer

a starting point for DNA polymerisation - makes a new 5-3 primer.

Question 8

Helicase

honeydew mellon

Answer 8

unwinds the helical double- stranded DNA to give 2 parental templates

Question 9

Topoisomerase

tomato

Answer 9

releases the tension generated by the unwinding of the helix

does this by nicking and rejoining the DNA strands

Question 10

Single stranded DNA binding protein (SSBP)

Strawberry

Answer 10

prevents the unwound double stranded helix from reforming and degrading

Question 11

DNA polymerase I

Answer 11

removes the RNA primer and fills the gap with the DNA nucleotides (DNA polymerase)

Question 12

DNA ligase

Answer 12

joins the newly synthesised ozaki fragments together and creates phosphodiester bonds

Question 13

RNase H

DNA polymerase activity

Answer 13

is an endonuclease enzyme that recognises DNA-RNA hybrids and degrades and removes the RNA part.
it is then extended and nucleotides fill the gap, on lagging strands.

Question 14

Eukaryotic replication

Answer 14

multiple, larger and linear (not single circles)

multiple origins of replication (single in eukaryotic)

Question 15

EXOnuclease

Answer 15

the proof reading mechanism of DNA pol III that happens DURING DNA replication
removes the incorrect base, places the correct one and synthesis continues

Question 16

ENDOnuclease

Answer 16

molecule that removes incorrect DNA after replication has occurred.
removes from the middle and some regions around the affected nucleotide.
polymerase then comes and places the correct base and ligase joins the existing DNA to the new DNA.

Question 17

Importance of correcting DNA errors

Answer 17

if not corrected the DNA error becomes apart of the DNA template and becomes a permanent DNA mutation/ change.

Question 18

Polymerase Chain Reaction (PCR)

Answer 18

In virto method of making multiple DNA copies
only targeted DNA regions will be copied
rapid exponential increase of DNA molecules
method utilises cycles of heating and cooling

Question 19

PCR denaturation

Answer 19

94-98 degrees

temperature increased to seperate DNA strands high temp breaks the h bonds

Question 20

PCR annealing

Answer 20

45-70 degrees

temperature decreases to allow primers to base pair to complementary DNA template

Question 21

PCR extension

Answer 21

72 degrees

polymerase extends primer to form nascent DNA strand can survive high temps.

Question 22

exponential amplification

Answer 22

process is repeated 25-35 times and the region of interest is amplified exponentially

Question 23

DNA template

Answer 23

DNA molecule to which complementary nucleotides can be matched to make identical copies via synthesis

Question 24

Primers

Answer 24

provides a free 3 prime OH group, the chemical group that is essential to initiate DNA synthesis.
defines the region of the DNA molecule to be replicated

Question 25

Heat stable and DNA polymerase

Answer 25

enzyme which adds nucleotides complementary to the DNA template and joins them together to form phosphodiester bonds.

Question 26

dNTP’s

Answer 26

free nucleotides (equal amount of A,T,C,G) 
Building blocks used by the DNA Polymerase

Question 27

Buffer solution

Answer 27

solution that maintain the pH that the DNA template polymerase requires to work

Question 28

Divalent cations

Answer 28

‘co-factors’ - ions that are essential for DNA polymerase to work.