Cell division
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Transcript of Cell division
Cell Division
Mitosis
Meiosis
The Cell Cycle
The Cell Cycle
•G1 (Growth Stage) – the organelles start to double in number.• S (Synthesis Stage) – the DNA strands replicate.•G2 (Growth Stage) – more protein is made.
Mitosis• A process of cell division herein
two new daughter cells receive exactly the same number of chromosomes as the parent cell.• It includes four stages namely:
Prophase, Metaphase, Anaphase and Telophase.
The Process of Mitosis
Prophase• The nucleus
disappears.• The nuclear
membranes breakdown and disappears.
• Centrioles move toward the opposite poles.
Metaphase• Chromosomes
move toward and alignment at the center of the cell.
• Centromere of chromosomes attaches itself to a spindle fiber.
Anaphase• Chromatids
separate and each pair is pulled to each pole.• Cell membrane
begins to pinch together at the cell’s center.
Telophase• The nucleolus and
nuclear membrane appears.
• Chromosomes uncoil and become chromatin.
• Cell membrane completely pinches and centrioles replicate.
Meiosis• A cell division of diploid cells that produces haploid cells like sex cells.• It require to nuclear division: Meiosis I and Meiosis II.
Process of Meiosis
Meiosis IProphase I • The nucleus membrane and nucleolus disappears
• Spindle fibers begin to form.
Metaphase I • Crossing – over between the homologue pair happens• Spindle fibers completely form
Anaphase I • Homologues of each pair split and move to the opposite sides, the chromosomes number on each side is half the original number
Telophase I • The nucleolus appears• The nuclear membrane form• Pinching of the cell membrane is completed so there are
two ne cells
Meiosis IIProphase II • Spindle fibers begin to form
• The nuclear membrane breaks
Metaphase II • The chromosomes align at the center• Spindle fibers form completely
Anaphase II • The chromatids of each chromosomes are pulled apart and move toward opposite sides
Telophase II • The nuclear membrane appears
References
• Olivares, Maria, et. al. Science and Technology for the modern world. Textbook for second year. 2003. DIWA Scholastic Press Inc. Makati City