Reproduction
Cell Cycle
Mitosis and Meiosis
Cell Cycle
METHODS of CELL
REPRODUCTION include...
• Fission - binary = 2 equal halves
• Budding - outgrowths detach = new organism (unequal)
• Mitosis -asexually = identical genetic copies genetically equal
somatic cells
• Meiosis - sexually produces sperm & egg cells with 1/2
chromosome # & new gene combos
Mitosis
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Mitosis is a process of cell division which results in the production of two
daughter cells from a single parent cell. The daughter cells are identical to
one another and to the original parent cell.
In a typical animal cell, mitosis can be divided into four principals stages:
Prophase: The chromatin, diffuse in interphase, condenses into
chromosomes. Each chromosome has duplicated and now consists of
two sister chromatids. At the end of prophase, the nuclear envelope
breaks down into vesicles.
Metaphase: The chromosomes align at the equitorial plate and are held in
place by microtubules attached to the mitotic spindle and to part of the
centromere.
Anaphase: The centromeres divide. Sister chromatids separate and move
toward the corresponding poles.
Telophase: Daughter chromosomes arrive at the poles and the microtubules
disappear. The condensed chromatin expands and the nuclear envelope
reappears. Cytokinesis: The cytoplasm divides, the cell membrane
pinches inward ultimately producing two daughter cells .
Phases of Meiosis
Diagram of the stages of meiosis: two stage
division of a cell, producing gametes and halving
the number of chromosomes in its nucleus.
Prophase I: first phase of meiosis.
Metaphase I: second phase of meiosis.
Anaphase I: third phase of meiosis.
Telophase I: fourth phase of meiosis.
Prophase II: fifth phase of meiosis.
Metaphase II: sixth phase of meiosis.
Anaphase II: seventh phase of meiosis.
Telophase II: eight phase of meiosis.
Four cells: last phase of meiosis.