REPRODUKSI SEL.

Presentasi berjudul: "REPRODUKSI SEL."— Transcript presentasi:

1 REPRODUKSI SEL

2 Reproduksi protista berbeda dengan sel hewan lainnya
Jamur → spora Tanaman → biji Hewan → telur Protista → sel tunggal Sel anak → mempunyai membran, sitoplasma dan inti Inti mengandung DNA yang identik

3 Salah satu protista adalah amoeba
Amoebas → sangat tipis, membran sel fleksibel Bergerak dengan menjulurkan sitoplasma keluar membran dan membentuk pseudopods ("false feet") Di dalam sel terdapat ruang sbg organ percernaan

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5 REPRODUKSI SEL MITOSIS → sel somatik
MEIOSIS → sel seks atau gamet (spermatozoa dan ovum)

6 MITOSIS Interfase Metafase Anafase Profase Telofase
Terjadi sintesis protein; kromatin dan inti nampak jelas; replikasi DNA Kromatin tebal → kromosom; membran inti melebur; sentriol bergerak pada sisi yang berlawanan dan serabut spindel mulai terbentuk Kromosom yang dihubungkan spindel ada di tengah Kromosom memisah menuju ke kutub yang berlawanan Kromosom kembali berbentuk kromatin; speindel melebur; membran inti nampak; sentriol replikasi; terbentuk membran sel baru

7 Cell Reproduction Interphase (before Mitosis) Early Prophase Prophase Late Prophase Transition to Metaphase Metaphase Anaphase Telophase

8 MEIOSIS : Tahap-tahapnya sbb : Terdiri dari 2 fase :
Meiosis I : merupakan pembelahan yang memisahkan 2 kromosom homolog (kromatid), terjadi reduksi kromosom Meiosis II : merupakan pemisahan kromatid melalui pembelahan sentromer. Hasilnya : sel diploid menghasilkan 4 sel anakan yang haploid Tahap-tahapnya sbb :

9 PROPHASE I SYNAPSIS - the pairing and bonding together of homologous chromosomes to form tetrads Homologous chromosomes consist of one maternal and one paternal chromosome

10 PROPHASE I CROSSING-OVER:
Exchange of chromatid segments within tetrads to produce new allele combinations Nonsisters cross over, break, and rejoin Increases genetic variety VIEW OF NUCLEUS AND TETRADS

11 CROSSING -OVER Notice the exchange of segments that has happened in two places on the larger homologous pair This is crossing over

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13 METAPHASE I Tetrads line up in the middle of the cell in a straight line at equator Spindle fibers attach to only 1 kinetochore of each centromere

14 ANAPHASE I Tetrads are separated as homologous chromosomes are pulled to opposite poles of the cell (Remember: the chromosomes are still actually sister chromatids)

15 TELOPHASE I Cytokinesis may occur and two HAPLOID cells containing sister chromatids are produced A brief period of interkinesis occurs

16 INTERKINESIS A short interphase TELOPHASE I
like stage between divisions TELOPHASE I PROPHASE II

17 SEPARATES SISTER CHROMATIDS
MEIOSIS SEPARATES SISTER CHROMATIDS Fase I Fase II

18 PROPHASE II Nuclear membranes disappear Nucleoli disappear
Spindle fibers form Chromatin coils to form chromosomes What does this remind you of ? Prophase II is basically the same as mitosis prophase x 2

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20 METAPHASE II In metaphase II the two cells line up their chromosomes in the middle of the cell in a straight line at equator Again this is the same as mitosis metaphase - only two cells are doing it Each cell is doing it with only 1 chromosome of each kind, not pairs

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22 ANAPHASE II During this phase the centromeres of the chromosomes in the two cells divide and sister chromatids move to opposite poles of the cells Very mitosis-like again

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24 TELOPHASE II Final act of meiosis Nuclear membranes reappear
Nucleoli reappear Chromosomes uncoil to chromatin Spindle fibers disappear Cytokinesis occurs to produce a total of 4 haploid cells (N)

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27 MEIOSIS II PROPHASE II MEIOSIS II

28 Meiosis : Summary of reduction division

29 Phases of spermatogenesis (i.e., meiosis in males)

30 TERIMA KASIH