Metabolism and Survival - Genetic Control of Metabolism

Question 1

artificial chromosome

Answer 1

type of vector used in recombinant DNA technology which can carry larger fragments of foreign DNA that are required to be inserted into a host cell

Question 2

DNA ligase

recombinant DNA technology

Answer 2

enzyme which seals the DNA fragment into the plasmid to form a recombinant plasmid

Question 3

properties that make an effective vector

summary

Answer 3

• restriction sites for inserting DNA
• selectable marker genes
• origin of replication
• regulatory sequences to control gene expression

Question 4

selectable marker genes

properties that make an effective vector

Answer 4

these protect the microorganism from a selective agent that would normally kill or prevent growth, enabling scientists to determine whether the plasmid vector has been taken up by the host cell or not

e.g. marker gene - antibiotic resistance , selective agent - antibiotic

Question 5

restriction sites for inserting DNA

properties that make an effective vector

Answer 5

• the restriction site will conatin target sequences of DNA where restriction endonuclease cuts
• the same enzyme will be used to cut the gene from the chromosome to ensure that the sticky ends are complimentary, allowing ligase to seal the strands together

Question 6

origin of replication

properties that make an effective vector

Answer 6

• this is where DNA replication begins, and is the essential for the generation of many copies of the recombinant plasmid
• this means more copies of the gene are expressed producing more product per cell

Question 7

mutagenesis

Answer 7

• the creation of mutants by inducing mutations
• the rate of mutagenesis can be increased by exposing organisms to mutagenic agents e.g. UV light (radiation), mustard gas (mutagenic chemicals)

Question 8

mutagenic agent

Answer 8

agent which increases mutation rate when an organism is exposed to it

Question 9

recombinant DNA technology

Answer 9

the process of gene sequences being transferred from one organism to another

can be from one species to another

Question 10

restriction endonuclease

Answer 10

enzyme which is used to cut specific genes out of the donor organism and cut open the bacterial plasmids that receive the genetic infomation

Question 11

restriction site

Answer 11

• the location which restriction endonuclease cuts the DNA in such a way that it leaves sticky ends
• the target sequence is found on both DNA strands but running in opposite directions

—ACGT—
—TGCA—

Question 12

sticky ends

Answer 12

these are produced by cutting nuceotides on each strand several nucleotides apart to leave a short single stranded fragment

Question 13

vector

recombinant DNA technology

Answer 13

DNA molecule used to carry foreign genetic information into another cell

Question 14

strain improvement

wild strains need to be imrpoved to…

Answer 14

• produce larger quantities of target compound
• improve genetic stability
• improve ability to grow on low cost nutrients
• allow easy harvesting of the target compound

Question 15

strain improvement

recombinant DNA tech. means improvements can be made…

Answer 15

• amplify a specific metabolic step in a pathway to increase the yield of target compound
• remove inhibitory controls
• cause cell to secrete product into surroundings for ease of harvesting
• for safety, gene that prevent survival of microorganisms in the wild / external environment