Cell and Nuclear Division · Paper 1 — Free Biology HL Practice Questions

A species of grasshopper has a diploid chromosome number of 24. A cell is observed in prophase I of meiosis. How many chromatids are present in this cell?

A student examines a micrograph of a cell from the root tip of an onion. Individual chromosomes, each consisting of two sister chromatids, are aligned at the cell equator with no evidence of homologous pairing. Which stage does this cell most likely represent?

A drug prevents spindle fibre formation in human skin cells undergoing mitosis. The spindle assembly checkpoint monitors whether all chromosomes are correctly attached to spindle fibres before division proceeds. At which stage would these cells most likely become arrested?