Unit 2.7 Genetic control of metabolism Flashcards
How can wild strains of micro-organisms be improved?
- mutagenesis
- recombinant DNA technology
What improves the rate of mutation?
Mutagenic agents such as
- UV light and radiation
- mutagenic chemicals
some of the mutations that occur as a result of this may produce an improved strain of the micro-organism
what is a vector in biological terms?
A vector is a DNA molecule used to carry foreign genetic information into another cell
- Plasmids
- Artificial chromosomes
can both be used as vectors for recombinant DNA technology
Why might artificial chromosomes be preferable to plasmids as vectors?
When larger pieces of DNA are required to be inserted artificial chromosomes are preferable vectors than plasmids
What is the role of restriction endonucleases in DNA technology?
restriction endonucleases cut open plasmids and cut specific genes out of chromosomes leaving sticky ends
Why must the same restriction endonuclease be used to both cut open the plasmid and cut the required gene from the chromosome?
As by using the same restriction endonuclease the sticky ends are complementary to one another meaning that the required gene can be inserted into the plasmid vector and the enzyme Ligase can seal the gene into the plasmid
What is the role of ligase in recombinant DNA technology?
Ligase seals the gene into the plasmid using the complementary sticky ends
What do recombinant plasmids and artificial chromosomes contain?
- restriction sites
- regulatory sequences
- an origin of replication
- selectable markers
What is a restriction site?
A restriction site is an area that contains target sequences of DNA where specific restriction endonucleases cut
What is the role of regulatory sequences?
Regulatory sequences control gene expression
What does the origin of replication allow?
The origin of replication allows for the self replication of the plasmid/ artificial chromosome
What is a selectable marker?
Selectable markers are genes that protect an organism from a selective agent that would normally kill the organism
(e.g anti-biotic resistance genes that protect an organism from the selective agent of anti-biotics, that would otherwise kill the organism)
What does selectable markers being present in the vector ensure?
Selectable markers being present in the vectors ensures that only the micro-organisms that have taken up the vector will be able to grow in the presence of a selective agent
What is a selective agent?
A factor that causes all unadapted organisms to die
