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CELL CYCLEOver time, many cells die and need to be replaced. • Mitosis - The process by which a cell reproduces to
create two identical cells. • Daughter Cells - Two identical cells formed by
mitosis• Cell Cycle – 4 different stages of the cell’s life
leading to division into new daughter cells.– G1, S, G2, M
• Many of the abnormal traits of cancer cells are due to defects in genes that control cell division.
Cell Cycle
• The cell cycle consists of four stages G1, S, G2, and M.
• G1 and G2 are 'gap' phases in which the cell grows and prepares to divide.
• S in the synthesis phase in which the chromatin (DNA) is copied (replicated).
• M is the mitotic phase in which the cell physically divides into two daughter cells.
• Most cells are NOT actively dividing. These cells are in a resting state (G).
• Mitosis is a process where cells are produced for growth and/or replacing damaged or old cells
• Mitosis in normal cells produces two cells with identical genetic content.
• Mitosis has four sub-phases:
PROPHASE• Chromosomes condense, the nuclear membrane
breaks down, and spindle fibers form
METAPHASE
• The replicated chromosomes line up in the middle of the cell
ANAPHASE• Chromosomes separate and the cell becomes
elongated, with distinct ends (poles)
TELOPHASE
• Nuclear envelopes re-form at the two poles and new cell membranes begin to form to create two independent cells
CYTOKINESISthe division of the cytoplasm to make two complete daughter cells
• ANIMAL CELLS– Cell membrane pinches apart
into two equal parts with one nucleus in each daughter cell
• PLANT CELLS– Cell plate forms between two
nuclei– Cell plate develops into a cell
wall
Animations
http://www.johnkyrk.com/mitosis.html
http://www.hybridmedicalanimation.com/anim_mitosis.html
Activity
• Each person will need one sheet of paper. – Name, block and date at the top right.– Title: Mitosis Quiz
I will show each slide in turn. Number your answers according to the
numbered picture/word.Do not forget to label identifying marks on
pictures.
CYTOKINESIS1.
2.
3.
METAPHASE4.
5.
6.
PROPHASE7.
8.
ANAPHASE9.
10.