Describe genetic engineering as a process which involves modifying the…

The idea

Genetic engineering changes an organism's genome deliberately, so that the organism gains a characteristic people want. The genome is the full set of genetic material in the organism; modifying it means altering the DNA, usually by inserting a gene from another organism. The inserted gene is expressed and gives a new, desirable characteristic. For example, a gene for a human protein such as insulin can be inserted into a bacterium, so the modified bacterium makes human insulin. The key idea is that the change is intentional and directed at a chosen characteristic, not random like a mutation. Learners should recognise the definition, identify the genome as the target of modification, and distinguish genetic engineering from selective breeding, which does not directly alter DNA.

What earns the marks

• Genetic engineering is a process that modifies the genome of an organism.
• The genome is the organism's genetic material (its DNA).
• Modification introduces a gene, often from a different organism, into the genome.
• The purpose is to introduce desirable characteristics that the organism did not previously have.
• The inserted gene is expressed, so the organism produces the desired product or trait.
• Genetic engineering is deliberate and directed, unlike random mutation or selective breeding.

Common mistakes and how to put them right

• Thinking genetic engineering changes only the appearance of an organism.

  Put it right by stressing that the genome (DNA) itself is modified.

• Confusing genetic engineering with selective breeding.

  Put it right by noting that selective breeding chooses existing individuals to breed, whereas genetic engineering directly alters DNA.

• Believing the whole organism is replaced.

  Put it right by explaining that a gene is inserted into the existing organism's genome, which is then modified.

• Assuming any change to DNA counts, including random mutation.

  Put it right by stressing that genetic engineering is a deliberate, planned modification to introduce a chosen characteristic.

Exam tips

• Learn the definition word for word in meaning: modifying the genome to introduce desirable characteristics.
• When a question names an example such as insulin-producing bacteria, link it back to the inserted gene and the new characteristic.
• Eliminate options that describe selective breeding or natural mutation when the question asks about genetic engineering.