Genetic Control Of Metabolism

Question 1

What is mutagenesis?
What can it lead to?

Answer 1

• A process used to improve wild strains of micro-organisms by inducing mutations through exposure to uv light, radiation or chemicals.
• can lead to the development of improved strains that may have desirable traits.

Question 2

What can be used to improve wild micro-organisms?

Answer 2

-Recombinant DNA technology
-Mutagenesis

Question 3

True or False: All mutations produced by mutagenesis are beneficial.

Answer 3

False.

-While some mutations can lead to improved strains, others may be harmful or neutral.

Question 4

What does recombinant DNA technology involve?

Answer 4

The use of recombinant plasmids and artificial chromosomes as vectors.

Question 5

What is the role of restriction endonucleases in recombinant DNA technology?

Answer 5

They cut out specific genes from chromosomes, and then cut open plasmids, leaving sticky ends.

Question 6

What is the role of ligase in recombinant DNA technology?

Answer 6

Seals the desired gene into the plasmid.

Question 7

What are vectors in recombinant DNA technology?

Answer 7

DNA molecules used to carry foreign genetic information into another cell.

Question 8

What types of vectors are used in recombinant DNA technology?

Answer 8

• Plasmids
• Artificial chromosomes

Question 9

When are artificial chromosomes preferable to plasmids?

Answer 9

When larger fragments of foreign DNA are required to be inserted.

Question 10

What are sticky ends?

Answer 10

Complementary ends produced when the same restriction endonuclease is used to cut open the plasmid and the gene.

Question 11

What are restriction sites?

Answer 11

Target sequences of DNA where specific restriction endonucleases cut.

Question 12

What do regulatory sequences control?

Answer 12

Gene expression of the vectors own gene and the inserted gene

Question 13

What does the origin of replication allow?

Answer 13

Self replication of the plasmid/ artificial chromosome

Question 14

What is recombinant dna technology? (1)

Answer 14

The manipulation of the genome of an organism by transferrring genes from one organism into a host micro-organism

Question 15

What do recombinant plasmids and artificial chromosomes contain ? (4)

Answer 15

• restriction sites
• regulatory sequences
• origin of replication
• selectable markers

Question 16

Why are safety mechanism genes introduced in micro-organisms?

Answer 16

To prevent the survival of the micro-organism in an external environment

Question 17

Why are recombinant yeast cells sometimes used in protein production?

Answer 17

• They produce active forms of the protein which are inactive in bacteria
• plant or animal recombinant dna expressed in bacteria may result in polypeptides being incorrectly folded

Question 18

What are selectable markers? What do they allow? (2)

Answer 18

-Antibiotic resistance genes that protect the micro-organism from selective agents ( antibiotics) that would normally kill it / prevent growing
- These markers allow for the identification of successfully transformed cells.

Question 19

How do selectable marker genes function in vectors?

Answer 19

They ensure that only micro-organisms that have taken up the vector grow in the presence of the selective agent (antibiotic)