REPRODUKSI. Reproduksi merupakan sarana makhluk hidup untuk mempertahankan eksistensinya Reproduksi:

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2 REPRODUKSI Reproduksi merupakan sarana makhluk hidup untuk mempertahankan eksistensinya Reproduksi: Reproduksi Sel Reproduksi Tumbuhan Reproduksi Hewan dan Manusia

3 REPRODUKSI SEL Sel merupakan unit struktural dan fungsional terkecil dalam hierarki kehidupan Sel mengalami proses pertumbuhan, perkembangan dan perbanyakan. Pertumbuhan: Ukuran Perkembangan: Fungsi Perbanyakan: Jumlah

4 REPRODUKSI SEL Tiga macam cara reproduksi tingkat sel: Amitosis Mitosis Meiosis

5 AMITOSIS 100 µm (a) Reproduction. An amoeba, a single-celled eukaryote, is dividing into two cells. Each new cell will be an individual organism (LM). Figure 12.2 A

6 AMITOSIS Pembelahan sel tanpa melalui tahapan khusus. Dilakukan dengan proses kariokinesis langsung dilanjutkan dengan sitokinesis Digunakan sebagai cara perkembangbiakan oleh organisme tingkat rendah. Amitosis = Pembelahan biner = Pembelahan spontan

7 Pembelahan Biner pada E. coli Origin of replication E. coli cell Two copies of origin Cell wall Bacterial Chromosome Plasma Membrane Origin Origin

8 MITOSIS DAN MEIOSIS Merupakan pembelahan sel dengan melalui tahapan khusus Interfase G1 S G2 Fase mitotik Profase Metafase Anafase Telofase Sitokinesis

9 SIKLUS SEL INTERPHASE G 1 S (DNA synthesis) G 2 Figure 12.5

10 MITOSIS Pembelahan sel tanpa adanya reduksi jumlah kromosom Terjadi pada sel-sel somatis Dalam satu kali mitosis hanya sekali terjadi pembelahan (fase mitotik) Fungsi: Pertumbuhan, Perbaikan

12 MITOSIS Centrosomes (with centriole pairs) G 2 OF INTERPHASE PROPHASE PROMETAPHASE Chromatin (duplicated) Early mitotic spindle Aster Centromere Fragments of nuclear envelope Kinetochore Nonkinetochore microtubules Figure 12.6 Nucleolus Nuclear envelope Plasma membrane Chromosome, consisting of two sister chromatids Kinetochore microtubule

13 MITOSIS METAPHASE ANAPHASE TELOPHASE AND CYTOKINESIS Metaphase plate Cleavage furrow Nucleolus forming Figure 12.6 Spindle Centrosome at one spindle pole Daughter chromosomes Nuclear envelope forming

14 MITOSIS PADA SEL TUMBUHAN Nucleus Chromatine Nucleolus condensing Chromosome 1 Prophase. The chromatin is condensing. The nucleolus is beginning to disappear. Although not yet visible in the micrograph, the mitotic spindle is staring to from. Figure Prometaphase. Metaphase. The 2 3 We now see discrete spindle is complete, 4 Anaphase. The 5 Telophase. Daughter chromatids of each nuclei are forming. chromosomes; each and the chromosomes, chromosome have Meanwhile, cytokinesis consists of two attached to microtubules separated, and the has started: The cell identical sister at their kinetochores, daughter chromosomes plate, which will chromatids. Later are all at the metaphase are moving to the ends divided the cytoplasm in prometaphase, the plate. of cell as their in two, is growing nuclear envelop will fragment. kinetochore microtubles shorten. toward the perimeter of the parent cell.

15 Sitokinesis pada sel hewan Cleavage furrow 100 µm Contractile ring of microfilaments Daughter cells Figure 12.9 A (a) Cleavage of an animal cell (SEM)

16 Sitokinesis pada sel tumbuhan Vesicles forming cell plate Wall of patent cell 1 µm Cell plate New cell wall Figure 12.9 B Daughter cells (b) Cell plate formation in a plant cell (SEM)

17 MEIOSIS Pembelahan sel disertai adanya reduksi jumlah kromosom Terjadi pada sel-sel gamet Dalam satu kali meiosis terjadi dua kali pembelahan (fase mitotik) Fungsi: Reproduksi organisme tingkat tinggi

18 Interphase MEIOSIS Homologous pair of chromosomes in diploid parent cell Chromosomes replicate Homologous pair of replicated chromosomes Sister chromatids Diploid cell with replicated chromosomes Meiosis I 1 Homologous chromosomes separate Haploid cells with replicated chromosomes Meiosis II 2 Sister chromatids separate Figure 13.7 Haploid cells with unreplicated chromosomes

19 Interphase and meiosis I INTERPHASE MEIOSIS I: Separates homologous chromosomes PROPHASE I METAPHASE I ANAPHASE I Centrosomes (with centriole pairs) Sister chromatids Chiasmata Centromere (with kinetochore) Spindle Metaphase plate Sister chromatids remain attached Chromatin Chromosomes duplicate Nuclear envelope Tetrad Homologous chromosomes (red and blue) pair and exchange segments; 2n = 6 in this example Microtubule Homologous attached to chromosomes kinetochore separate Tertads line up Pairs of homologous chromosomes split up

20 Meiosis I

21 Telophase I, cytokinesis, and meiosis II MEIOSIS II: Separates sister chromatids TELOPHASE I AND CYTOKINESIS PROPHASE II METAPHASE II ANAPHASE II TELOPHASE II AND CYTOKINESIS Cleavage furrow Sister chromatids separate Haploid daughter cells forming Figure 13.8 Two haploid cells form; chromosomes are still double During another round of cell division, the sister chromatids finally separate; four haploid daughter cells result, containing single chromosomes

22 Oogenesis dan Spermatogenesis

23 Perbandingan Mitosis dan Meiosis MITOSIS MEIOSIS Parent cell (before chromosome replication) Chiasma (site of crossing over) MEIOSIS I Prophase Duplicated chromosome (two sister chromatids) Chromosome replication 2n = 6 Chromosome replication Prophase I Tetrad formed by synapsis of homologous chromosomes Metaphase Chromosomes positioned at the metaphase plate Tetrads positioned at the metaphase plate Metaphase I Anaphase Telophase Sister chromatids separate during anaphase Homologues separate during anaphase I; sister chromatids remain together Daughter cells of meiosis I Anaphase I Telophase I Haploid n = 3 2n Daughter cells of mitosis 2n MEIOSIS II n n n n Daughter cells of meiosis II Figure 13.9 Sister chromatids separate during anaphase II

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SIKLUS PEMBELAHAN SEL

SIKLUS PEMBELAHAN SEL Keberlanjutan kehidupan didasarkan pada reproduksi dari sel-sel atau pembelahan sel Figure 12.1 Proses pembelahan sel Merupakan bagian terintegrasi dari siklus sel Ada tiga macam