EDEXCEL IGCSE BIOLOGY - (5C) GENETIC MODIFICATION

(5.12) What is the role of restriction enzymes in genetic modification?

Restriction enzymes cut DNA at specific sites, creating sticky ends for insertion of genes.

(5.12) What is the role of ligase enzymes in genetic modification?

Ligase enzymes join pieces of DNA together, sealing sticky ends to form recombinant DNA.

(5.13) What is a vector in genetic engineering?

A carrier that transfers DNA into a host cell, commonly a plasmid or virus

(5.13) How do plasmids act as vectors in genetic engineering?

Plasmids are circular DNA molecules that can take up foreign DNA and insert it into bacterial cells.

(5.13) How do viruses act as vectors in genetic engineering?

Viruses can carry recombinant DNA and inject it into host cells during infection.

(5.14) How is human insulin produced using genetically modified bacteria?

The insulin gene is inserted into a bacterial plasmid, which is then placed into bacteria grown in a fermenter to produce large quantities of insulin.

(5.14) What are the steps for producing insulin using bacteria?

1) Restriction enzyme cuts the insulin gene from human DNA (leaving sticky ends)

2) The same restriction enzyme cuts open a bacterial plasmid (leaving complementary sticky ends)

3) Insulin gene inserted into plasmid. Sticky ends join by complementary base pairing

4) DNA ligase joins the gene permanently into the plasmid (recombinant plasmid)

5) Recombinant plasmid inserted into bacterial cell

6) Bacteria grown in a fermenter

7) Insulin extracted and purified

(5.15) How are genetically modified plants used to improve food production?

They can be engineered for insect resistance, herbicide tolerance, or improved nutritional value, resulting in higher yields.

(5.16) What does the term transgenic mean?

An organism that has received genetic material from a different species.