Chromosome behaviour in mitosis — FAQ

In Cambridge 9700 Biology, chromosome behaviour in mitosis refers to the precise, orchestrated movements and structural changes of chromosomes through prophase, metaphase, anaphase, and telophase. This ensures that each new daughter cell receives an exact, identical set of chromosomes. You can master these stages with our free premium lessons and practice using past papers!

Mitosis is essential for several vital processes: it enables growth in multicellular organisms by increasing cell numbers, facilitates the repair of damaged tissues and replacement of worn-out cells, and serves as the basis for asexual reproduction in many species. Its primary role is to produce genetically identical daughter cells, maintaining genetic stability.

While the fundamental chromosome movements are similar, key differences exist. Animal cells form a cleavage furrow during cytokinesis to divide the cytoplasm, and they possess centrioles within their centrosomes which organise the spindle fibres. Plant cells, however, form a cell plate to build a new cell wall between daughter cells and typically lack centrioles, forming their spindle directly from microtubule-organising centres.

The cell cycle is controlled by a set of regulatory proteins, primarily cyclins and cyclin-dependent kinases (CDKs). These proteins work at specific checkpoints (e.g., G1, G2) to ensure that cellular processes like DNA replication are complete and accurate before allowing the cell to proceed to the next stage, such as mitosis.

Cancer is a disease of uncontrolled mitosis. Mutations in genes that regulate the cell cycle (proto-oncogenes and tumour suppressor genes) can cause cells to divide excessively and without control, leading to the formation of a tumour.