12: Biotechnology & Bananas Flashcards
Why has genetic engineering faced resistance for certain traits and crops?
Due to environmental concerns (e.g., resistant weeds, non-target insect harm), ethical issues, distrust of biotech companies, and technical challenges with complex traits.
What are genetically modified (GM) Bt crops?
Crops engineered to produce δ-endotoxins from Bacillus thuringiensis, which kill insect pests by rupturing their gut lining.
What is glyphosate and why is it widely used?
A broad-spectrum herbicide with low soil mobility and short half-life, effective against many weeds and considered safer for humans.
How is heat-tolerant rice genetically modified?
By adding extra copies of the gene for the D1 subunit of Photosystem II, which helps repair heat-induced damage and sustain photosynthesis.
How were modern bananas domesticated?
By hybridizing seeded wild species Musa acuminata and Musa balbisiana, producing sterile, seedless varieties like AAA bananas.
What is a corm and how does it relate to bananas?
A swollen underground stem used for vegetative propagation in seedless bananas.
What is the Cavendish banana?
The dominant global banana variety, sterile and propagated by corms, currently threatened by Panama disease TR4.
What is Panama Disease and why is TR4 concerning?
A fungal disease caused by Fusarium oxysporum that blocks water/nutrient transport in bananas. TR4 infects Cavendish bananas and has no effective resistance.
Why are monocultures like the Cavendish banana vulnerable?
Lack of genetic diversity means one disease can wipe out the entire crop.
There’s no resistance spread through sexual reproduction.
What are some risks and benefits of GM crops like Bt corn and glyphosate-resistant soybeans?
Benefits: Increased yield, pest resistance, reduced pesticide use.
Risks: Environmental impacts, resistant pests/weeds, socioeconomic issues.
How can scientists and policymakers address GMO skepticism?
Through transparent research, education campaigns, ethical regulation, and public engagement.
Compare traditional breeding to genetic engineering (e.g., CRISPR).
Traditional breeding is slower and less precise.
Genetic engineering targets specific genes, enabling faster, more controlled improvements.
What is an ascomycete?
A fungus that produces spores in sac-like asci; Fusarium belongs to this group.
What is a transgenic plant?
A plant genetically modified with DNA from another species.
