A cytogeneticist prepared a chromosome spread from a mammalian cell culture to analyze its karyotype.
During the preparation of the chromosomes for microscopy, the cells were placed in a solution that had a slightly higher (less negative) water potential than the cell cytoplasm. Suggest two steps in the process of how this procedure moved the chromosomes apart without bursting the cell.
The chromosomes in the karyotype are arranged in homologous pairs. What is a homologous pair of chromosomes?
Give two ways in which the arrangement of prokaryotic DNA is different from the arrangement of eukaryotic DNA in the chromosome spread.
3 exam-style questions on AQA A Level Biology DNA, genes and chromosomes. Each one has a worked solution and a mark scheme showing where the marks go.