2.7 Genetic Control of Metabolism

Question 1

Describe what a wild strain of a micro-organism is?

Answer 1

It is the phenotype of the typical form of a species of micro-organism as it occurs in nature.

Question 2

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

Answer 2

Mutagenesis

Recombinant DNA technology

Question 3

What is Mutagenesis?

Answer 3

the creation of mutations through the use of mutagenic agents in the effort of producing an improved strain of micro-organism.

Question 4

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

Answer 4

Horizontal Gene Transfer

Question 5

Describe ‘Transformation’ in relation to horizontal gene transfer

Answer 5

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

Question 6

How can new genotypes of fungi be produced?

Answer 6

Reproducing sexually - mixing together different existing strains

Question 7

Describe the process of ‘Recombinant DNA technology’

Answer 7

Processing of transferring a desirable gene from one species to another

Question 8

Describe the function of ‘Restriction Endonuclease’

Answer 8

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

Question 9

Describe the process of genetic engineering

Answer 9

• 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 10

Describe the function of ‘Ligase’

Answer 10

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

Question 11

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

Answer 11

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

Question 12

Identify the three features of an effective plasmid vector

Answer 12

a) Restriction Sites
b) Selectable Markers
c) Origin of Self Replication

Question 13

What is the ‘Origin of Self Replication’

Answer 13

Region of the plasmid that contains the genes from self replication

Question 14

What is a ‘Selectable Markers’

Answer 14

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

Question 15

What is the ‘Restriction Site’ of a plasmid

Answer 15

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

Question 16

What is a ‘selectable’ marker gene

Answer 16

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

Question 17

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

Answer 17

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

Question 18

Why would a selectable marker be used?

Answer 18

It will only be present in the genetically modified organisms so can be used to kill or prevent growth of non-genetically modified organisms. Ensuring that only the micro-organisms that have taken up the vector grow.

Question 19

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

Answer 19

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