Unit 2 - KA 7: Genetic Control

Question 1

What is a wild strain of microorganisms?

Answer 1

These are strains that are found in nature and may be useful for industrial processes.

Question 2

How can strains of bacteria be improved?

Answer 2

Mutagenesis

recombinant DNA technology

Question 3

Describe the application of mutagenesis.

Answer 3

Mutagenesis is the creation of mutations

This can be increased artificially through
radiation (e.g. UV light)
Mutagenic chemicals (e.g. mustard gas)

Question 4

Why are new mutations important.

Answer 4

As a source of variation within a population of microorganisms.

Question 5

Define Recombinant DNA technology.

Answer 5

a technique involving the transfer of genes from a plant or animal into a microbe.
This allows the production of a plant oranimal protein in a bacterial cell.

Question 6

Define the term vector.

Answer 6

A vector is a DNA molecule that is used to carry foreign genetic information into another cell.

Question 7

Give the two examples of vectors.

Answer 7

Plasmids

Artificial chromosomes

Question 8

Describe the preference in vectors.

Answer 8

Artificial Chromosomes are preferred for larger fragments of foreign DNA.

Question 9

What enzymes are used in recombinant DNA technology

Answer 9

Restriction endonuclease

Ligase

Question 10

Describe the use of Restriction endonuclease

Answer 10

Restriction endonucleases cut open plasmids and specific genes out of chromosomes, leaving sticky ends.

Question 11

Describe the use of ligase.

Answer 11

Ligase joins two different fragments of DNA together.

Question 12

Describe Sticky ends

Answer 12

Sticky ends are pieces of DNA that have unpaired nucleotides at either end of them. -▮_

Question 13

Define the restriction site

Answer 13

the specific site where the enzyme cuts the vector.

Question 14

What is the importance of using the same restriction endonuclease to cut the gene and plasmid?

Answer 14

This results in complementary sticky ends being produced, meaning the gene can be sealed into the plasmid.

Question 15

Name the features of an effective vector.

Answer 15

Origin of Replication
Restriction Site
Regulatory sequence
Selectable Markers

Question 16

Describe Origin of Replication

Answer 16

a particular sequence in a genome at which replication is initiated. Allows self-replication. Essential for future copying of plasmid.

Question 17

Describe the regulatory sequence

Answer 17

Controls gene expression of both plasmid and artificial chromosome

Question 18

Describe Selectable markers

Answer 18

Selectable marker genes present in the vector ensure that only micro-organisms that have taken up the vector grow in the presence of the selective agent
(antibiotic).

Question 19

What safety mechanism is introduced to microorgansims?

Answer 19

genes to prevent the microorganisms surviving outside the medium prevent the chances of an uncontrollable outbreak.

Question 20

What is the problem with using prokaryotic cells for eukaryotic proteins?

Answer 20

Differences in protein synthesis may cause the expression of an inactive polypeptide due to incorrect folding.

Question 21

What is used as an alternative to prokaryotic cells?

Answer 21

Yeast cells successfully produce an active protein.

Question 22

What is the drawback of using yeast cells instead of prokaryotic cells?

Answer 22

The Yeast cells’ optimum culturing conditions are more demanding than prokaryotes.