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Cell Division Rubie Maranan-Causaren


The cell cycle.


DNA REPLICATION


Phases

Activities G1

Interphase Cell cycle

S G2

Cell Division

Mitosis

Karyokinesis Meiosis Cytokinesis


Interphase

• • • •

Nucleus Nuclear membrane Nucleoli Chromatin network


Prophase


Figure 9 9.3 3


Metaphase


Anaphase


Telophase p


Whitefish blastula


onion root tip p


centrioles ti l

MITOSIS

INTERPHASE

Figure 6.3. Mitosis. This type of nuclear division ensures that each daugther cell has same chromosomal number (diploid=2n) as that of the parent cell.


Film clip Film clip2


MEIOSIS


Chromosome number?


(double threads)

“synapsis and crossing over”

(thick threads)

Homology search

“rough rough pairing pairing” (yolked threads) (Thin threads)

Figure 6.4. Meiosis. A diagrammatic representation of the major events occurring during meiosis (example in a male animal with a diploid number of 4).


Karyotype1


Karyotype2


Karyotype3


Figure 10 10.1 1


Chiasma and crossing over


How meiosis works Stages of meiosis Random orientation of chromosomes spermatogenesis


Spermatogenesis (2n)

(2n)

spermatogonium

(n)

(n)

(n)

(n)


Meiosis vs. mitosis


C it i Criteria Kinds of cells no. of division/s per cycle no. off daughter d ht cells ll formed f d per cycle l chromosome no. of daughter cells progeny/daughter cells ti off cycle time l uses

Mitosis Mit i somatic cells one t two diploid (2n) genetically identical th throughout h t life lif growth, repair, and asexual reproduction

Meiosis M i i gametes (egg and sperm) two f four haploid (n) genetically different completed l t d after ft sexuall maturity (in humans) sexual reproduction, generating new gene combinations


Figure 10 10.8 8


Salamat……..


Cell Division