REVIEW
GIVE THE STAGES OF EACH ILLUSTRATION
Producing Haploid
Daughter cells
MEIOSIS
OBJECTIVES
1. Define Meiosis.
2. Enumerate the stages of Meiosis.
3. Give the significance of Meiosis in
Sexual Reproduction.
Meiosis- Consists of two successive divisions of the nucleus called meiosis I and meiosis II
- Results in four haploid daughter cells
- Only happens in the sex gonads ( testes and ovary)
Stages of MeiosisFirst Meiotic Division• Prophase I• Metaphase I• Anaphase I• Telophase ISecond Meiotic Division• Prophase II• Metaphase II• Anaphase II• Telophase II
Events for First Meiotic Division
• Prophase I- chromosome becomes visible and the nuclear membrane disappears; homologous chromosome appears and share fragments called crossing over
Metaphase I- complete disappearance of nuclear membrane and appearance of spindle fiber; centromeres attached to the spindle fiber and lies on the metaphase plate or central plate
Anaphase I- homologous chromosome separates from each other but centromere do not divide; chromosome continues to consists of two chromatids
Telophase I- chromosomes are still doubled; nuclear membrane is formed and disappearance of spindle fiber
Second Meiotic Division
Prophase II- cells have one chromosome
Metaphase II- chromosomes align at the metaphase plate; centromeres divide thus separating the chromatids
Anaphase II- each new daughter cell move towards opposite poles
Telophase II- spindle disappears; nuclear membrane is formed; nuclei are formed and cytokinesis happens
Gametogenesis - a process of producing sex cells
• Spermatogenesis- sperm production; occurs during puberty stage and continues throughout life
• Oogenesis- production of female gametes or ova
Oogenesis
SeatworkAnswer Activity Sheet on “ Inferring Difference”
E:\Seatwork #3 in meiosis.docx
Assignment #4• Answer activity sheet on Sexual reproduction in lower forms of life and animals
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