AP BIOLOGY

Detailed explanation-1: -Homologue pairs separate during a first round of cell division, called meiosis I. Sister chromatids separate during a second round, called meiosis II. Since cell division occurs twice during meiosis, one starting cell can produce four gametes (eggs or sperm).

Detailed explanation-2: -Anaphase I: In anaphase I, the attachment of the spindle fibers is complete. The homologous chromosomes are pulled apart and move towards opposite ends of the cell.

Detailed explanation-3: -Prophase I: The homologous chromosomes line up together. During this time, a process that only happens in meiosis can occur. This process is called crossing over (Figure below), which is the exchange of DNA between homologous chromosomes. Crossing over forms new combinations of alleles on the resulting chromosome.

Detailed explanation-4: -No DNA replication occurs during the interphase which precedes meiosis II. Prophase II is the first step in meiosis II. Like in mitosis and meiosis I, chromatin condenses, centrosomes move to opposite poles and a spindle apparatus forms.