Mitosis and Meiosis Stages, Structure and Difference.pptx

Mitosis and Meiosis Stages, Structure and Difference

1. GPB-121 Department of Agriculture Botany “ Fundamentals of Genetics ” Mitosis and Meiosis Stages, Structure and Difference

2. It is a type of cell division for somatic cells and for the asexual reproduction of unicellular eukaryotic cells. Mitosis is a process of nuclear division in eukaryotic cells that  occurs when a parent cell divides to produce two identical daughter cells .   Interphase ==> Prophase ==> Metaphase ==> Anaphase ==> Telophase ==>  Cytokinesis Discover by – Flemming (1882) What is Mitosis ? Cell division in which one parent cell (2n) is undergoes division into two daughter cell (n).

3. INTRAPHAS (More growth occurs) Resting stage (Seen under – Light microscope). 24 hrs. Cell under goes mitosis (Long phase). Divided into three phases Intra-Phase C) Gap phase 2  ( G2 ) 2 nd gap Condense RNA and Protein Synthesis . Mitosis Gap phase 1  ( G1 )- Major growth occurs. 1 st gap Synthesis of Protein and RNA ( 30-40% ). B) Synthesis phase  ( S )- Phase between G1 and G2 Phase. DNA Synthesis (2 sister chromatids produce).

4. Mitosis Stages

5. PROPHAS (Nucleolus is imp) Chromosome pair up. Nucleolus and nucleolus membrane dispersed (Breakdown). Two chromatids seen. At end of prophase the Thread like occurs. Chromosome are short and thick. METAPHAS (long stage about 20 min. r equired) Chromosome pair up. Nucleolus and nucleolus membrane dispersed (Breakdown). Two chromatids seen. At end of prophase the Thread like occurs. Chromosome are short and thick. Metakineis – Movement of Chromosome

6. ANAPHAS (Shortest Phase) Smallest form of Mitosis. Two poles are shows i.e. S-N Poles. TELOPHAS (now there are two) Chromosome are coil. Spindle fibers are dispersed and nucleus membrane are formed. Nucleus and nucleus membrane get reorganized. Cytokinesis Complete end of Telophase

7. It is the type of cell division for the production of gametes in sexual reproduction. It reduces the number of chromosomes in the parent cell by half and produces four gamete cells. One parent cell (2n) under goes divided into four daughter (n) cell. The process results in four daughter cells that are haploid, which means they contain half the number of chromosomes of the diploid parent cell . 1 st division is – Meiotic 2 division 2 nd division is- Mitotic Discover by – Farmer and Moore (1905). What is Meiosis ?

8. Meiosis Meiosis I – Reduction division Meiosis II – Equation division Intra-phase I Pro-phase I Meta-phase I Ana-phase I Telo -phase I Cytokinesis I Intra-phase II Pro-phase II Meta-phase II Ana-phase II Telo-phase II Cytokinesis II 1. Intra-phase I G1 Phase- Protein and RNA synthesis S phase – 0.03 % DNA Present, DNA replicate Zyogtene G2 phase – Entry of cell depend upon S- Phase.

9. Leptotene  – Chromosomes are visible   under light microscope. Condensation of chromosomes takes place. Zygotene   – Pairing of homologous   chromosomes takes place i.e   synapsis occurs . 0.03% DNA replication, Z-DNA synthesis. 3. Pachytene   – Synapsis is completed/ End of Synapsis. 4. Diplotene   –The separation of homologous chromosomes i.e. Bivalent. 5. Diakinesis   – chiasma formation. 2. Pro-phase I (longest phase) Time required - 5 days to 5 hrs.

10. Difference

11. Similarities