Mitosis

Cell Cycle: Mitosis

Cell Cycle consists of…

Interphase, Mitosis and Cytokinesis.

1.      Cell is usually in Interphase.

2.     Interphase has three sub-phases called G1 phase, the S phase and the G2 phase.

3.      G1: Cell grows

4.      S Phase: Cell continues to grow and copies its chromosomes. This phase duplicates chromosomes.

5.      G2 phase: Cell grows and completes preparations for cell division.

6.     Mitosis consists of Prophase, Prometaphase, Metaphase, Anaphase, and Telophase.

7. Cytokinesis actually divides the cell into two identical cells.

Mitosis: It is a process when eukaryotic cells undergo nuclear division. Mitosis conserves chromosome number by replication chromosomes.

Steps of Mitosis:

1.      Prophase: It is the first stage of mitosis, where the chromatin is condensing and the mitotic spindle begins to form. The nucleolus and nucleus are still present and connected.

–          Chromosomes are visible

–          Nucleoli disappears

–          Mitotic spindle begins to form.

–           Made out of centrosomes and microtubules

2.      Prometaphase: It is the second stage of mitosis, where chromosomes having identical sister chromatids appear. The nuclear envelope fragments, and the spindle microtubules attach to the kinetochores of the chromosomes.

–          Nuclear envelope is broken down into fragments

–          Kinetochore microtubule attach at the kinetochore of the chromosome.

–          Nonkinetochore microtubules interact with eachother from the opposite side of the spindle.

3.      Metaphase: It is the third stage of mitosis, where the spindle is complete and the chromosomes attach to microtubules at their won kinetochores. Chromosomes are all aligned at the metaphase plate.

–          Centrosomes are at the opposite side of the cell

–          Chromosomes line up in the middle of the cell, known as the metaphase plate.

–          The entire microtubules is called the spindle, because of the shape.

4.      Anaphase: It is the fourth stage of mitosis, where the chromatids of each chromosome have separated and the daughter chromosomes are moving to the opposite ends of the cell.

–          Two sister chromatids separateand is pulled to the opposite ends of the cell.

–          The cell elongates

–          By the end of anaphase, the end of each side of the cell is identical.

5.      Telophase: It is the fifth and final stage of mitosis, where the daughter nuclei begin to form and cytokinesis is starting.

–          Nuclear envelop starts to form from the fragments of the parent cell’s nuclear envelop.

–          Chromosomes become less condensed.

–          There is total of two identical nuclei.

CYTOKINESIS: Physical division of the cell into two daughter cells.

–          In animal cells: Cleavage furrow, which is the pinching in the middle of the cell.

–          In plant cells: Plant plate: To divide the cell into two.

Check this out!

This is an animation from ‘Cells alive’

http://www.cellsalive.com/cell_cycle.htm

Here is an animation for mitosis:)

http://wormclassroom.org/cell-division-and-polarity

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Mitosis Quiz