SA2

Question 1

Biotechnology

Answer 1

The use of technology

to modify organisms

to make them more useful to humans

Question 2

Genetic engineering

Answer 2

Modifying a DNA sequence by removing an unwanted gene or inserting a desired gene

Modifying the genotype to produce a desired phenotype

Question 3

Restriction enzymes/ Restriction endonucleases

Answer 3

A group of proteins found in bacteria

Highly specific -
ALWAYS cut at restriction sites

*at the backbone

Question 4

Function of restriction endonuclease

Answer 4

To carry out Restriction digestion

Cut DNA by breaking phosphodiester bonds

Question 5

Restriction fragments

Answer 5

Pieces of DNA cut by restriction enzymes

Question 6

Blunt ends

Answer 6

When all the bases of cut DNA remain paired

Question 7

Sticky ends

Answer 7

When the bases of cut DNA our unpaired

Question 8

Function of DNA ligase

Answer 8

To join pieces of DNA back together

By forming phosphodiester bonds

Question 9

Recombinant DNA

Answer 9

Any DNA sequence that contains DNA from another source

Question 10

Function of polymerase chain reaction

Answer 10

To amplify DNA

To make many copies of a DNA sequence

*number of DNA doubled after each round

Question 11

Polymerase chain reaction steps

• Require
  1) Taq polymerase
• catalyse formation of new strand

2) Primers
- initiate replication

Answer 11

1. Denaturation
2. Annealing
3. Extension

Question 12

1. Denaturation

Answer 12

Sample heated

Hydrogen bonds broken

Double-stranded DNA converted to single-stranded DNA

Question 13

2. Annealing

Answer 13

Sample cooled

Hydrogen bonds form between single-stranded DNA and primers

Primers anneal to single-stranded DNA

Question 14

3. Extension

Answer 14

Sample heated

Taq polymerase binds to primers and adds DNA nucleotides

Form double-stranded DNA

Question 15

Function of gel electrophoresis

Answer 15

To separate DNA based on fragment length

Used to confirm that the correct gene/ sequence has been amplified with PCR or for DNA profiling

Question 16

Function of CRISPR/ Cas9

Answer 16

Cuts out specific, whole sequences of DNA

Locates target sequence inside cells and deactivates them by cutting them

Can remove unwanted sequences or add desired sequences

*permanent

Question 17

Spacer DNA

Answer 17

Sequences that are recognized and cut out by enzymes and proteins coded for by the Cas genes

Located between CRISPR sequences

Question 18

Cas genes

Answer 18

Codes for proteins and enzymes that recognize and cut out DNA sequences that match spacer DNA

Question 19

CRISPR sequences

Answer 19

Where spacer is located

Sequences where we insert spacer DNA

Question 20

Genetically modified organisms

Answer 20

Any organism that has gained a new gene or allele through artificial means

Question 21

Gene cloning

Answer 21

Making copies of functional genes that can produce proteins

• Producing specific proteins

Question 22

Gene cloning steps

Answer 22

1. Extract plasmid
2. Cut out desired gene from chromosome and cut plasmid with same restriction enzyme
3. Mix desired gene with cut plasmids and DNA ligase - produce recombinant plasmids
4. Mix recombinant plasmid with bacterial culture - so plasmids absorbed into bacterial cells

Question 23

Recombinant plasmids

Answer 23

Plasmid containing the new gene

Question 24

Transformation

Answer 24

The process of absorbing the recombinant plasmid

Plasmids taken up by bacteria

Question 25

Gene therapy

Answer 25

When gene cloning is applied for medical purposes To treat genetic diseases caused by a single gene

Question 26

Viral vector

Answer 26

Modified virus that is no longer able to cause disease Inject target sequence into cell

Question 27

Advantages of genetic engineering

Answer 27

Altering chromosomes of the cell is permanent Using viral vector uses natural functioning of viruses to transfer to target DNA into host cell Highly targeted nature of CRISPR Cas9 can edit genomes quickly and relatively cheaply Gene cloning produces easy to harvest up your product Limitless

Question 28

Disadvantages of genetic engineering

Answer 28

Can be very difficult to target cells Gene therapy often only somatic - still heritable Use of viral vector could cause disease or side effects Long-term effects not fully known Reduced genetic variation - negative ecological effects Could create social iniquity