GCSE Combined Science revision · Biology: homeostasis, inheritance and ecology
Higher tier students must complete Punnett squares and explain the outcomes. In genetic engineering, enzymes cut the required gene out, and the gene is inserted into a vector, usually a bacterial plasmid or a virus, which carries it into the target cells. Genes are put into plants or animals at an early stage so the characteristic develops. Benefits include crops resistant to disease; concerns include effects on wild populations and human health.
Watch out A 3:1 ratio of phenotypes is not the same as a 1:2:1 ratio of genotypes.
Describe how a gene is inserted into a bacterial cell.
Answer Enzymes cut out the gene, insert it into a plasmid, and the plasmid enters the bacterium
Two Tt pea plants are crossed. T (tall) is dominant. Out of 400 offspring, how many would you expect to be short?
What is used as a vector in genetic engineering?
A cross of Tt × Tt gives a phenotype ratio of:
21 official questions in 14 papers since 2018. The latest:
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