2.7 Genetic Control of Metabolism

Question 1

What are the three ways wild types of microorganisms can be improved?

Answer 1

Mutagenesis
Selective Breeding
Genetic Engineering

Question 2

Describe ‘Selective Breeding’

Answer 2

Process by which only those cells with desired characteristics are breed

Question 3

What is Mutagenesis?

Answer 3

The deliberate introduction of mutations by exposing the cells to mutagenic agents such as UV light and mustard agents

Question 4

How can genetically new bacteria strains arise even though they reproduce asexually?

Answer 4

Horizontal Gene Transfer

Question 5

Describe ‘Conjunction’ in relation to horizontal gene transfer

Answer 5

• Between two neighbouring cells
• Conjunction tube will form
• Plasmid will pass from one cell to another
• Both cells now have plasmids present

Question 6

Describe ‘Transformation’ in relation to horizontal gene transfer

Answer 6

Transformation is when the bacterial cell takes up foreign DNA from it surrondings

Question 7

How can new genotypes of fungi be produced?

Answer 7

Reproducing sexually - mixing together different existing strains

Question 8

Describe the process of ‘Recombinant DNA technology’

Answer 8

Processing of transferring a desirable gene from one species to another

Question 9

Describe the function of ‘Restriction Endonuclease’

Answer 9

Degradation enzymes that cuts open the plasmid and cuts the desired gene out of the genome of the other organism

Question 10

Describe the process of genetic engineering

Answer 10

• Restriction Endonuclease cuts the plasmid open
• Same RE cuts out the desired gene
• The gene is inserted into plasmid and ‘glued in’ by the Ligase
• The plasmid is taken up into the bacterium

Question 11

Describe the function of ‘Ligase’

Answer 11

Ligase glues the sticky ends together, sealing the gene into the plasmid

Question 12

Why must the same restriction enzyme be used to cut both the plasmid and the desired gene?

Answer 12

To ensure the sticky ends are complementary and the base pairs match up

Question 13

The quantity of a desired product can be increased by inserting what other genes?

Answer 13

• Genes that remove inhibitory controls

- Genes that amplify specific metabolic steps

Question 14

What is a ‘transgenic’ organism?

Answer 14

A organism that carries a gene transferred from a different organism

Question 15

Identify the three features of an effective plasmid vector

Answer 15

a) Restriction Sites
b) Marker Genes
c) Origin of Self Replication

Question 16

What is the ‘Origin of Self Replication’

Answer 16

Region of the plasmid that contains the genes from self replication

Question 17

What is a ‘Marker gene’

Answer 17

A marker gene is a gene that acts as a recognisable tag for a cell that has taken up the transferred plasmid

Question 18

What is the ‘Restriction Site’ of a plasmid

Answer 18

A specific DNA sequence that can be cut open using the restriction endonuclease

Question 19

What are the two types of marker genes

Answer 19

Selectable

Screening

Question 20

What is a ‘selectable’ marker gene

Answer 20

A selectable marker gene is a gene that will protect the organism from something that would normally kill it eg. antibodies

Question 21

What is a ‘screening’ marker gene

Answer 21

A screening marker gene is a gene that changes the physical appearance of the cell

Question 22

Why would you use recombinant DNA technology with yeast cells rather than bacterial cells?

Answer 22

Due to the fact that a yeast cell is eukaryotic, it has the facilities for post translational modification and protein folding

Question 23

Describe a safety precaution to prevent survival of recombinant microbe outside lab

Answer 23

Introduction of genes that prevent survival outside of culture
Example: gene that forces reliance on a chemical only found in culture medium

Question 24

What type of marker gene would be required if the biologist wants to introduce antibiotic resistance into the cell culture which has uptaken the plasmid

Answer 24

Selectable