Telophase Characteristics Quiz

Centrosome and Mitosis

• The centrosome contains centrioles and a pericentriolar cloud of material with γ-tubulin rings.
• It is the principal microtubule-organizing center (MTOC) of the cell.
• Centrosomes migrate to opposite poles of the cell, and from them, spindle fibers and astral rays of the mitotic spindle polymerize.

Chromosome Structure

• Chromosomes consist of two parallel sister chromatids attached at the centromere.
• Kinetochores develop at the centromere region and function as MTOCs.

Mitosis Phases

Prometaphase

• Nuclear envelope disappears, allowing chromosomes to disperse in the cytoplasm.
• Kinetochores complete development and attach to specific spindle microtubules, forming kinetochore microtubules.

Metaphase

• Duplicated condensed chromosomes align at the equatorial plate of the mitotic spindle and attach to spindle microtubules at their kinetochore.

Anaphase

• Chromatids separate at the centromere, and daughter chromosomes move to opposite poles of the cell.
• The spindle elongates.
• In the later stages of anaphase, a cleavage furrow begins to form around the cell as the contractile ring, a band of actin filaments, contracts.

Telophase

• Each set of chromosomes reaches the pole, and a deepening of the cleavage furrow occurs.
• The midbody (containing overlapping polar microtubules) is formed between the newly forming daughter cells.
• Microtubules in the midbody are depolymerized, facilitating cytokinesis and formation of two identical daughter cells.
• The nuclear envelope is reestablished around the condensed chromosomes, and nucleoli reappear.

Apoptosis (Programmed Cell Death)

• Apoptosis is the method of removing cells from tissues in an orderly fashion as a part of normal maintenance or during development.
• Cells that undergo programmed cell death have several morphological features.

Meiosis

• Meiosis is a type of cell division that occurs in gametes.
• It involves two successive divisions (meiosis I and meiosis II).
• Meiosis I involves genetic mixing, while meiosis II involves the separation of sister chromatids.

Meiosis I

• Anaphase I is similar to anaphase in mitosis, except that each chromosome consists of two chromatids that remain held together.
• Telophase I is similar to telophase in mitosis, with the nuclear envelope reestablished and two daughter cells formed via cytokinesis.
• Each daughter cell contains 23 chromosomes (n) but has a 2C DNA content.

Meiosis II

• Equatorial division (meiosis II) begins soon after the completion of meiosis I, following a brief interphase without DNA replication.
• The sister chromatids are portioned out among the two daughter cells formed in meiosis I.
• The stages of meiosis II are similar to those of mitosis, with the stages named similarly (prophase II, metaphase II, anaphase II, and telophase II).
• Meiosis II occurs more rapidly than mitosis.

Cytoplasm

• The cytoplasm contains three main structural components: organelles, inclusions, and the cytoskeleton.