The red flour beetle (Tribolium castaneum) is a major agricultural pest that infests stored grain and cereal products.
Malathion is an organophosphate insecticide used to control beetle infestations. It prevents the breakdown of the neurotransmitter acetylcholine at cholinergic synapses.
Explain why malathion is an effective insecticide.
Resistance to malathion is caused by a dominant allele, RRR.
Two resistant beetles mate and produce non-resistant offspring.
Draw a genetic diagram (such as a Punnett square) to show how these non-resistant offspring can be produced.
When scientists studied the resistant beetles, they found two different genotypes:
Scientists observed that the non-resistant allele (rrr) never disappears completely from the wild population, even in areas where malathion is heavily applied. Explain why.
Name the enzyme used to join two sections of DNA together in genetic engineering.
Scientists believe they can control the beetle population using genetic engineering. They want to insert a gene into male beetles that destroys all of their sperm containing an X chromosome.
Explain how this method of genetic engineering would rapidly reduce the wild beetle population.
97 exam-style questions on OCR GCSE Biology 5.1 Inheritance, covering 5.1.1 The genome, 5.1.2 Environment and phenotype, 5.1.3 Variants and mutations, 5.1.4 How genetic variants influence phenotype, 5.1.5 Asexual and sexual reproduction, 5.1.6 Haploid and diploid, 5.1.7 Meiotic cell division, 5.1.8 Single gene inheritance, 5.1.9 Predicting single gene crosses, 5.1.10 Sex determination, 5.1.11 Multiple gene inheritance, and 5.1.12 Development of our understanding of genetics. Each one has a worked solution and a mark scheme showing where the marks go.