AP BIOLOGY

Detailed explanation-1: -A unique feature of the nucleus is that it disassembles and re-forms each time most cells divide. At the beginning of mitosis, the chromosomes condense, the nucleolus disappears, and the nuclear envelope breaks down, resulting in the release of most of the contents of the nucleus into the cytoplasm.

Detailed explanation-2: -Mitosis is a process of nuclear division in eukaryotic cells that occurs when a parent cell divides to produce two identical daughter cells. During cell division, mitosis refers specifically to the separation of the duplicated genetic material carried in the nucleus.

Detailed explanation-3: -Division of the nucleus during cell division is called karyokinesis and is followed by cytokinesis which is the division of the cell cytoplasm. Both karyokinesis and cytokinesis are parts of the cell cycle. Karyokinesis occurs in all four stages-prophase, metaphase, anaphase and telophase.

Detailed explanation-4: -The large central nucleolus, which occupies about 20% of the nuclear volume, persists throughout the cell cycle. At mitosis, the nucleolus divides and moves to the poles in association with the chromosomes. The structure of the mitotic spindle and its relationship to the nucleolus are unknown.

Detailed explanation-5: -There are two kinds of nuclear division-mitosis and meiosis. Mitosis divides the nucleus so that both daughter cells are genetically identical. In contrast, meiosis is a reduction division, producing daughter cells that contain half the genetic information of the parent cell.