Cell Cycle: M Phase Mitosis and Cytokinesis. Cell Division (M phase) Occurs in two stages –...

Cell Cycle: M Phase

Mitosis and Cytokinesis

Cell Division (M phase)

•Occurs in two stages–Mitosis (nuclear division)–Cytokinesis (cytoplasmic division)

Prophase (Pieces)

• Genetic material condenses/coils and duplicated chromosomes (sister chromatids) becomes visible

• Spindle (from centrioles) begins to form

• Nucleolus disappears• Nuclear envelope breaks

down• Centrioles move to opposite

ends of the cell– *Plant cells do not have

centrioles

Metaphase (Middle)

• Centromeres of duplicated CHX line up across the center of the cell• Spindle fibers connect to each

centromere

Anaphase (Apart)• Sisters chromatids

separate and begin to move apart – now individual CHX• Individual CHX move

along spindle fibers to the opposite ends of the cell• Anaphase is over when

CHX are completely separated into two groups

Telophase (Two)• Condensed CHX begin to

spread out and de-condense back into chromatin• Nuclear envelopes re-

form around each cluster of CHX• Spindle begins to break

apart• Nucleolus becomes

visible in each daughter cell

Mitosis is Complete

But the M phase is not…

Cytokinesis

• After mitosis is complete, all that remains of the M phase of the cell cycle is the process of cytokinesis.• Cytokinesis is the division of the

cytoplasm itself/splits one cell into two• Occurs concurrently with

telophase• Cell division is complete

The rigid cell wall will not allow the cell to pinch like an animal cell.

How are plant cells different from animal cells?

And how will this difference affect cytokineses?

PINCHING

How are plant cells different from animal cells?

• Plant cells form cell plates to divide the cell.

• The cell plates develop into cell membranes, separating the two daughter

cells• A cell wall forms in between the two new

membranes

• Difference between plant and animal cell cytokinesis:

• Animal cells pinch, forming cleavage furrow while…

• Plant cells form cell plates to divide the cell

CELL PLATE

Additional Notecards

• Cytokinesis• Interphase–G1–S–G2