The phases of Mitosis

Question 1

What are the phases of Mitosis?

Answer 1

Interphase (G1, S, and G2) and (M) Phase (Prophase, Pro-metaphase, Metaphase, Anaphase, & Telophase and Cytokinesis)

Question 2

What are the functions of G1 (first gap)

Answer 2

Cells grow and prep for cell division.

Question 3

What is happening in S phase of Interphase?

Answer 3

Chromosomes are replicated here, and cells also continue to grow in preparation for cell division.

Question 4

What is going on in G2 (second gap) of interphase?

Answer 4

The third and final stage of interphase. This is the transition stage to M phase.

• a nuclear envelope incloses the nucleus.
• the nucleus contains one or more nucleoli.
• two centrosomes have formed by duplication of a single centrosome. Centrosomes are regions in animal cells that organize the mictrotubles of the spindle. Each centrosome contains two centrioles.
• Chromosomes duplicated during S phase, cannot be seen individually because they have not yet condensed.

Question 5

What is happing in prophase?

Answer 5

• The chromatin fibers become more tightly coiled, condensing into discrete chromosomes observable with a light microscope.
• The nucleoli disappear
• Each duplicated chromosome appears as two identical sister chromatids joined at their identical centromeres and in some species all long their arms by cohesions.
• The mitotic spindle begins to form. Composed of centrosomes and mictrotubules that extends from the centrosomes called asters.
• The centrosomes move away from each other, propelled partly by the lengthening microtubules between them.

Question 6

What is happing in prometaphase?

Answer 6

• The nuclear envelope breaks.
• The microtubules extending from each centrosome can invade the nuclear area.
• The chromosomes have become even more condensed.
• Each of the two chromatids of chromosome now have a kinetochore, a specialized structure of a centrosome.
• Some of the microtubules attach to the kinetochore microtubules, which jerk the chromosomes back and forth.
• Nonkinetochore microtubules interact with those from opposite pole of spindle.

Question 7

What is happening in metaphase?

Answer 7

• The centrosomes are now at the opposite poles of the cell.
• The centrosomes convene at the metaphase plate, a plane that is equidistant between the spindles two poles. The chromosomes centrosomeres lie at the metaphase plate.
• For each chromosome, the kinetochores of the sister chromatids are attached to kinetochore microtubules coming from opposite poles.

Question 8

What is happening in the Anaphase?

Answer 8

• Anaphase is the shortest stage of mitosis, often lasting only a few minutes.
• Anaphase begins when the cohesion proteins are cleaved. This allows the two sister chromatids of each pair to suddenly part. Each chromatid becomes a full-fledged chromosome.
• The two free daughter chromosomes begin moving toward opposite ends of the cell as their kinetochore microtubules shorten. because these microtubules are attached at the centromere region, the chromosomes move centromeres first.
• The cell elongates as the nonkinetochore microtubules lengthen.
• By the end of anaphase, the two ends of the cell have equivalent and complete collections of chromosomes.

Question 9

What is going on in telophase?

Answer 9

• Two daughter nuclei form in the cell. Nuclear envelopes arises from the fragments of the parent cells nuclear envelope and other portions of the endomembrane system.
• Nucleoli reappear.
• The chromosomes become less condensed.
• Any remaining spindle microtubules are depolymerized
• Mitosis, the division of one nucleus into two generally identical nuclei is now complete.

Question 10

What is going on in cytokinesis?

Answer 10

• The division of the cytoplasm is usually well under way by late telophase, so the two daughter cells appear shortly after mitosis.
• In animal cells, cytokinesis involves the formation of a cleavage furrow, which pinches the cell in two.