This question is on meiosis: Variation occurs during meiosis, give the two ways this happens (include the phases where it occurs) (4 marks)
During prophase 1, homologous chromosomes will pair up to form a bivalent, this is where crossing over can occur. Chromatids will twist around each other and will break and reform, resulting in crossing over.During metaphase 1 the homologous chromosomes will align at the metaphase plate, this lining up will be completely random due to different alleles and crossing over, this is called independent assortment. This will also occur in metaphase 2.
Related Biology A Level answers
All answers ▸What are some of the non-specific, first-line immune defences in humans?
(a) (i) Give a biological molecule that contains: 1. nitrogen 2. phosphorous (ii) Describe the role of microorganisms in producing nitrates from the remains of dead organims.
Suggest and explain two ways the cell-surface membranes of the cells lining the intestine may be adapted to allow rapid transport of nutrient
Why does an enzyme only catalyse one reaction?