AP Bio Unit 5 Cheat Sheet

Meiosis - a type of cell division that results in four daughter cells each with half the number of chromo­somes of the parent cell. During the process of meiosis, each sex cell only contains n amounts of chromo­somes, so that the resulting gamete would be 2n, or a diploid cell. Meiosis consists of two steps: Meiosis l and Meiosis ll.
Meiosis l Prophase l - the first phase in meiosis l where chromo­somes condense, homologous chromo­somes pair up to form tetrads, and crossing over occurs. Metaphase l - homologous (pairs of mother and father chromo­somes) align at the equator of the cell. Anaphase l - homologous chromo­somes seperate and move towards opposite poles of the cell. Telophase l - divided genetic material gathers at both poles forming two new cells.
Meiosis ll Prophase ll - chromo­somes condense and become visible while spindle fibers form and attach to these chromo­somes. Metaphase ll - chromo­somes align at the equator of the cell before they are pulled apart. Anaphase II - the sister chroma­tids, now individual chromo­somes, separate and move towards opposite poles of the cell. Telophase ll - the final phase in meiosis where nuclear membranes form around each set of chromo­somes, which decondense back into chromatin. The cytoplasm then divides resulting in four haploid daughter cells.