Inheritance & EvolutionHigher Tier
Higher Enzyme Steps and Ethical Debate on GM Crops
Part of Genetic Engineering — GCSE Biology
This higher tier covers Higher Enzyme Steps and Ethical Debate on GM Crops within Genetic Engineering for GCSE Biology. Genetic modification, gene therapy, and biotechnology applications It is section 8 of 11 in this topic. This section is most useful once the core foundation idea is secure, because it adds the detail that pushes answers higher.
Topic position
Section 8 of 11
Practice
25 questions
Recall
20 flashcards
Higher Enzyme Steps and Ethical Debate on GM Crops
Detailed enzyme mechanism:
- Restriction enzymes recognise palindromic sequences — sequences that read the same on both strands in opposite directions (e.g., GAATTC/CTTAAG).
- They make staggered cuts, leaving single-stranded overhangs ("sticky ends") of typically 4 bases.
- These sticky ends have complementary sequences that allow the gene and the vector to anneal (join by hydrogen bonding) before ligase permanently seals the covalent backbone bonds.
- Not all bacteria take up the recombinant plasmid — scientists use antibiotic resistance marker genes in the plasmid to identify which bacteria have been successfully transformed.
Ethical debate — GM crops:
- Arguments for: Could reduce global hunger by increasing yields; golden rice could prevent vitamin A deficiency affecting 250 million children; reduces pesticide use and its environmental damage; precision and speed compared to selective breeding.
- Arguments against: Gene transfer to wild relatives could create resistant weeds; unknown long-term ecological consequences; large corporations control seeds, reducing farmer autonomy; ethical concerns about "playing God" with natural organisms; some religious and cultural objections.
- The scientific consensus: Currently approved GM crops are safe for human consumption — but this does not resolve the separate environmental and ethical debates.