The fruit fly, Drosophila melanogaster, has autosomal genes for body colour and wing shape. Gene B/b is involved in the production of body colour: • B = dominant allele for brown body colour • b = recessive allele for black body colour. Gene D/d is involved in wing shape: • D = dominant allele for straight wing • d = recessive allele for curved wing. A dihybrid test cross was carried out between flies heterozygous for body colour and for wing shape and flies homozygous recessive for body colour and for wing shape. (a) Table 5.1 shows the number of offspring of each phenotype obtained in the test cross. [Table 5.1]

The foxglove, Digitalis purpurea, is a common plant in many parts of the world. Fig. 5.1 shows a foxglove. [Figure 5....

The black pigment melanin, which contributes to hair, skin and eye colour, is produced by cells known as melanocytes.

MELAS syndrome is an inherited disease caused by a mutation in a gene located in mitochondrial DNA (mtDNA). All mtDNA...

An animal cell and a plant cell are placed in distilled water. The animal cell swells and bursts, while the plant cel...

The R groups (side chains) of amino acids can be hydrophobic, hydrophilic, acidic or basic. The diagram shows four di...

Which describes the emulsion test for the presence of lipids?