IB DP Biology 1.6 Cell division Question Bank SL Paper 1

B

Anaphase is one of the stages of mitosis, the process of cell division in eukaryotic cells. In anaphase, the sister chromatids separate and migrate to opposite poles of the cell. This results in the formation of two identical sets of chromosomes, one for each daughter cell. Anaphase is preceded by metaphase and followed by telophase.
To observe anaphase on onion root tip cells, you need to prepare a slide with a thin layer of onion root cells stained with a dye that binds to DNA, such as aceto-carmine or aceto-orcein. You also need to treat the cells with hydrochloric acid to break down the cell wall and other tissues. Then, you can use a compound microscope to examine the slide and look for cells that have two distinct groups of chromosomes at opposite ends of the cell. These are the cells in anaphase. You can also compare them with cells in other stages of mitosis, such as prophase, metaphase and telophase.
An onion root tip is a good material to study mitosis because it is a rapidly growing part of the onion and has large chromosomes that are clearly visible under the microscope.