AP BIOLOGY

Detailed explanation-1: -In the third step of mitosis, called metaphase, each chromosome lines up in a single file line at the center of the cell. By this point in time, the membrane enclosing the nucleus has dissolved, and mitotic spindles have attached themselves to each chromatid in all the chromosomes.

Detailed explanation-2: -In prophase I of meiosis, the homologous chromosomes form the tetrads. In metaphase I, these pairs line up at the midway point between the two poles of the cell to form the metaphase plate.

Detailed explanation-3: -During prophase I, homologous chromosomes pair up and exchange sections of DNA. This is called recombination or crossing over. This is followed by metaphase I where the connected pairs of chromosomes align at the middle of the cell.

Detailed explanation-4: -Near the end of metaphase I, the homologous chromosomes align on the metaphase plate.

Detailed explanation-5: -During prophase I, homologous chromosomes pair and form synapses, a step unique to meiosis. The paired chromosomes are called bivalents, and the formation of chiasmata caused by genetic recombination becomes apparent.