Mitosis

MITOSIS

Prophase

Metaphase

Anaphase

Telophase

Overview

OVERVIEW Mitosis or cell division

enables organisms to grow and reproduce.

Occurs in four main steps (prophase, metaphase, anaphase, and telophase).

During the process “replicated genetic material in a parent cell is equally distributed to two daughter cells”

Accounts for about 10% of the time in the cell cycle

PROPHASE Nucleoli disappear Chromatin fibers become coiled into

chromosomes (two chromatids attached at a centromere).

Spindle fibers form in the cytoplasm at opposite ends of the cell.

Later, the nuclear envelop dissolves. Centrioles on each side of the cell attach their

spindle fibers to the kinetochores, located on each chromosome’s centromere, aligning the chromosomes in the middle of each cell.

Images

PROPHASE PICTURES

Animal Plant

ASCARIS MEGALOCEPHALA

Onion Cell

Info

METAPHASE Accounts for 4% of the cell cycle duration Centrosomes are at opposite poles of the

cell The chromosomes are now at their most

highly condensed form, and are arranged at the center of cell, along the metaphase plate, equidistant from the two poles.

Sister chromatids face opposite poles of the cell to prepare for division.

Images

METAPHASE PICTURES

Animal Plant

ASCARIS MEGALOCEPHALA Onion Cell

Info

ANAPHASE Sister chromatids separate Spindle fibers move the separated

chromatids to opposite poles of the cell The poles of the cell move further from

each other, elongating the cell Each pole has an equivalent and

complete set of chromosomes.

Images

ANAPHASE PICTURES

Animal Plant

ASCARIS MEGALOCEPHALA

Onion Cell (Mid Anaphase)

Info

TELOPHASE Microtubules continue to elongate the cell Daughter nuclei begin to form at the poles

where the chromosomes have gathered Nuclear envelopes form from fragments of

the old nuclear envelope Nucleoli begin to reappear Cytokinesis is underway-in animals a

cleavage furrow appears

Images

TELOPHASE PICTURES

Animal Plant

ASCARIS MEGALOCEPHALA

Onion Cell

Info

GLOSSARY Centrosome- an area in the cell where microtubles are produced (within an animal cell centrosome there is a pair of the centrioles).Cleavage furrow- The term to describe the pinching of an animal cell into two cells, the mechanism of cytokinesis.Cytokinesis- the division of the original cell's cytoplasm.Kinetochore- a specialized region of the centromere to which spindle fibers attach, pulling the chromosome to the center of the cell. Spindle Fibers- “An aggregate of microtubules that move chromosomes during cell division.”

Works Cited http://faculty.clintoncc.suny.edu/faculty/michael.gregory/files/Bio%20101/Bio%20101%20Lectures/Mitosis/mitosis.htm

http://library.thinkquest.org/C0123260/basic%20knowledge/mitosis.htm

http://faculty.clintoncc.suny.edu/faculty/michael.gregory/files/Bio%20101/Bio%20101%20Laboratory/mitosis/ascaris.htm

http://www.superstock.com/stock-photography/Ascaris+megalocephala

http://biology.about.com/od/mitosis/ss/mitosisstep_2.htm

http://biology.about.com/od/mitosis/ig/Mitosis-Image-Gallery/