The Process of Meiosis also known as PMAT.pptx

Meiosis Process in our cells and it's function

1. MEOISIS Presented by Jestria Castillo and Lance Gajela

2. WHAT IS MEIOSIS? Meiosis is a type of cell division that only happens in sex cells. Its purpose is to create gametes that contain half the number of chromosomes. When a sperm and egg unite, they form a zygote — a new human being.

3. MITOSIS MITOSIS VS MEIOSIS CHARACTERISTIS MEIOSIS Sex cells (sperm/egg) Type of cell 4 haploid cells (23 chromosomes each) Two (Meiosis I and II) One Body cells (e.g., skin, liver) Yes, all different 2 identical cells (46 chromosomes) No, all identical Number of divisions Result Genetic variety?

4. STAGES OF MEIOSIS 🔹 Meiosis I 🔹 Meiosis II Each part has 4 phases: Prophase, Metaphase, Anaphase, Telophase — but something special happens in Meiosis I! Meiosis has two main parts:

5. MEIOSIS I

6. PROPHASE I Nuclear membrane and nucleolus starts to disappear. Spindle fibers become visible. Crossing over takes place between 2 non-sister chromatids along a point called chiasma. Crossing over results in genetic recombination and accounts for genetic variation. Homologous chromosomes have the same length, staining pattern, and position of the centromere. Homologous chromosomes are important because they allow for the recombination and random segregation of genetic material from the mother and father into new cells. Tetrad has four sister chromatids

7. METAPHASE I Tetrads are moved by the spindle fibers to the equator of the cell. Homologous pairs of the chromosomes come together

8. ANAPHASE I Homologous pains of chromosomes (dyads) separate and migrate toward their respective poles.

9. TELOPHASE I Two daughter cells are completely divided during The number of chromosomes in both cells is the same A nuclear envelope and nuclei reappear and the chromosomes become less visible.

10. MEIOSIS II

11. PROPHASE II The chromosomes condense, and a new set of spindle fibers forms. The chromosomes begin moving toward the equator of the cell

12. METAPHASE II The centromeres of the paired chromatics align along the equatorial plate in both cells.

13. ANAPHASE II The stage when sister chromatics of every chromosome separate and begin to move towards the opposite ends of the cell.

14. TELOPHASE II The cells pinch in the center and divide again. The final outcome is cholesterol and different proteins that aid in substance transport.

15. Summary of the Process Starts with one diploid cell (46 chromosomes). Goes through two divisions: • Meiosis I: separates homologous pairs. • Meiosis II: separates sister chromatids.

16. WHY IS MEIOSIS IMPORTANT? It provides genetic variety in humans and animals. It keeps the chromosome number stable from generation to generation. It's essential for sexual reproduction.