SIKLUS SEL

1. SIKLUS SEL Made Pharmawati

2. Figure 12.1 Kontinuitas kehidupan Didasarkan atas reproduksi sel atau pembelahan sel

3. 100 µm (a) Reproduction. An amoeba, a single-celled eukaryote, is dividing into two cells. Each new cell will be an individual organism (LM).

4. 200 µm 20 µm (b) Growth and development. This micrograph shows a sand dollar embryo shortly after the fertilized egg divided, forming two cells (LM). (c) Tissue renewal. These dividing bone marrow cells (arrow) will give rise to new blood cells (LM). Figure 12.2 B, C • Organisme multiseluler tergantung pada pembelahan sel untuk: • Perkembangan (dari sel yang terfertilisasi) • Pertumbuhan • Repair

5. Semua organisme kompleks berasal dari a single fertilized egg. Melalui pembelahan sel, jumlah sel meningkat Sel kemudian terspesialisasi dan berubah menjadi fungsinya masing2

6. Tipe pembelahan sel • Mitosis: • Growth, development & repair • Asexual reproduction (yields identical cells) • Occurs in somatic (body) cells • Meiosis: • Sexual reproduction (yields different cells) • Occurs in specific reproductive cells

7. Phases of Mitosis 1. Prophase 2. Prometaphase 3. Metaphase 4. Anaphase 5. Telophase • Pembelahan sel menghasilkan sel anak yang secara genetik identik • Sel harus menduplikasikan material genetiknya • Before they divide, ensuring that each daughter cell receives an exact copy of the genetic material, DNA

8. Distribution of Chromosomes During Cell Division • Padapersiapancell division, DNA bereplikasidankromosommemadat • Tiap chromosome yang terduplikasimemilikiduasister chromatids, yang berpisahselama cell division • Sentromermerupakandaerahcekingdari chromosome yang terduplikasi, diamanduachromatidsterikatdengandekat

9. Figure 12.1 metahase Anaphase prophase Telophase Cytokinesis 1X

10. Cell division results in genetically identical daughter cells • Sel menduplikasikan material genetik sebelum membelah, utk memastikan bahwa tiap sel anak menerima copy DNA dengan tepat • A cell’s endowment of DNA (its genetic information) is called its genome • Molekul DNA dalam sel ter-pack menjadi kromosom

11. SetiapspesieseukariotmemilikisejumlahtertentukromosompadanukleusSetiapspesieseukariotmemilikisejumlahtertentukromosompadanukleus • Selsomatik(nonreproductive) memiliki 2 set kromosom • Gamet(reproductive cells: sperm and eggs) memilikijumlahkromosomsetengahjumlahkromosomselsomatik • Kromosomeukaryotikterdiridarikromatin, sebuahkomplex DNA dan protein yang memampatselamapembelahansel

13. 0.5 µm A eukaryotic cell has multiplechromosomes, one of which is represented here. Before duplication, each chromosomehas a single DNA molecule. Chromosomeduplication(including DNA synthesis) Once duplicated, a chromosomeconsists of two sister chromatidsconnected at the centromere. Eachchromatid contains a copy of the DNA molecule. Centromere Sisterchromatids Separation of sister chromatids Mechanical processes separate the sister chromatids into two chromosomes and distribute them to two daughter cells. Centromeres Sister chromatids Figure 12.4

14. Pembelahan sel pada eukariot terdiri dari: • Mitosis, the division of the nucleus • Cytokinesis, the division of the cytoplasm • Gamet diproduksi dalam pembelahan sel yang disebut meiosis • Meiosis menghasilkan sel anak yang tidak identik dengan induk yaitu hanya memiliki 1 set kromosom

15. Pada pembelahan sel, fase mitosis bergantian dengan interfase • Pada tahun 1882, ahli anatomi Jerman Walther Flemming mengembangkan pewarna untuk mengamati kromosom selama mitosis dan sitokinesis • Bagi Flemming, terlihat sel tumbuh membesar • Sekarang dapat diketahui banyak peristiwa kritis terjadi selama tahapan siklus sel

17. INTERPHASE S(DNA synthesis) G1 CytokinesisMitosis G2 MITOTIC(M) PHASE Figure 12.5 Fase-fase dalam siklus sel • Siklus sel terdiri dari • Fase mitosis • Interphase • Interphase • G1 phase • S phase • G2 phase • The mitotic phase • mitosis • cytokinesis

18. Phases of the Cell Cycle • Siklusselterdiridari • Mitotic (M) phase (mitosis and cytokinesis) • Interphase(cell growth and copying of chromosomes in preparation for cell division) • Interphase(terdiridarisekitar 90% darisiklussel) yang dapatdibagidalam sub fase: • G1 phase (“first gap”) • S phase (“synthesis”) • G2 phase (“second gap”)

19. G2 OF INTERPHASE PROMETAPHASE PROPHASE Centrosomes(with centriole pairs) Aster Fragmentsof nuclearenvelope Early mitoticspindle Kinetochore Chromatin(duplicated) Centromere Nonkinetochoremicrotubules Kinetochore microtubule Chromosome, consistingof two sister chromatids Nuclearenvelope Plasmamembrane Nucleolus Figure 12.6 • Mitosis terdiri dari 5 phases • Prophase • Prometaphase

20. METAPHASE ANAPHASE TELOPHASE AND CYTOKINESIS Metaphaseplate Cleavagefurrow Nucleolusforming Nuclear envelopeforming Daughter chromosomes Centrosome at one spindle pole Spindle Figure 12.6 • Metaphase • Anaphase • Telophase

21. The mitotic spindle • mikrotubul yang mengontrol pergerakan kromosom selama mitosis • Spindle muncul dari sentromer • spindle microtubules • asters

22. Perakitan spindle microtubules dimulaidarisentrosom - microtubule organizing center • Sentrosombereplikasimembentukduasentrosom yang bermigrasikekutub yang berlawanan, dan spindle microtubules tumbuhdarisentrosom • Aster(a radial array of short microtubules) munculdaritiapsentrosom

23. The Spindle Spindle memiliki struktur seperti web terbuat dari microtubule . Sangat penting pada mitosis karena mengatur kromosom untuk berada pada posisi yang benar Mitotic center A cell atmetaphase a spindle Microtubule

24. Aster Centrosome MetaphasePlate Sisterchromatids Kinetochores Overlappingnonkinetochoremicrotubules Kinetochores microtubules 0.5 µm Microtubules Chromosomes Figure 12.7 Centrosome 1 µm • Some spindle microtubules • Berikatan dengan kinetochores chromosomes

25. Chromosomes attached to spindle during nuclear division

26. Two kinds of microtubules • Kinetochore microtubules : berikatan dengan kinetochores chromosomes dan menggerakkan kromosom ke daerah metafase • Nonkinetochores: overlap satu sama lain tetapi tidak berikatan dengan chromosome 1 µm

28. Kinetochore Spindlepole Figure 12.8 • Pada anafase, sister chromatid berpisah • Dan bergerak sepanjang kinetochore microtubules menuju arah berlawanan ujung sel

29. Initiation ofAnaphase

30. The microtubules shorten by depolymerizing at their kinetochore ends • Nonkinetechore microtubules from opposite poles • Overlap and push against each other, elongating the cell • In telophase • Genetically identical daughter nuclei form at opposite ends of the cell

32. CYTOKINESIS • Division of the cytoplasm • Mitosis is the splitting of the nucleus. Cytokinesis is the splitting of cytoplasm • It usually begins during ANAPHASE

33. Cleavage furrow 100 µm Contractile ring of microfilaments Daughter cells (a) Cleavage of an animal cell (SEM) • Pada sel hewan • Cytokinesis terjadi oleh proses yang disebut cleavage, membentuk sebuah a cleavage furrow

34. Vesiclesforming cell plate Wall of patent cell 1 µm Cell plate New cell wall Daughter cells Figure 12.9 B (b) Cell plate formation in a plant cell (SEM) • Pada sel tumbuhan, selama cytokinesis • Terbentuk plat sel (cell plate)

35. 2 3 5 1 4 Chromatinecondensing Nucleus Chromosome Nucleolus Metaphase. The spindle is complete,and the chromosomes,attached to microtubulesat their kinetochores, are all at the metaphase plate. Prophase. The chromatinis condensing. The nucleolus is beginning to disappear.Although not yet visible in the micrograph, the mitotic spindle is staring to from. Prometaphase.We now see discretechromosomes; each consists of two identical sister chromatids. Laterin prometaphase, the nuclear envelop will fragment. Telophase. Daughternuclei are forming. Meanwhile, cytokinesishas started: The cellplate, which will divided the cytoplasm in two, is growing toward the perimeterof the parent cell. Anaphase. Thechromatids of each chromosome have separated, and the daughter chromosomesare moving to the ends of cell as their kinetochoremicrotubles shorten. Figure 12.10 • Mitosis in a plant cell

36. Purpose of Interphase – to duplicate cell contents; 90% of the cell’s growth cycle Purpose of Mitosis – to divide the genetic material into exact two halves Purpose of Cytokinesis – to divide all other contents (except nucleus) into two cells

37. Prokaryotes (bacteria and archaea) reproduce by a type of cell division called binary fission In binary fission – The bacterial chromosome replicates – The two daughter chromosomes actively move apart

38. Cell wall Origin of replication LE 12-11_1 Plasma membrane E. coli cell Bacterial chromosome Chromosome replication begins. Soon thereafter, one copy of the origin moves rapidly toward the other end of the cell. Two copies of origin

39. Cell wall Origin of replication Plasma membrane E. coli cell Bacterial chromosome LE 12-11_2 Chromosome replication begins. Soon thereafter, one copy of the origin moves rapidly toward the other end of the cell. Two copies of origin Origin Origin Replication continues. One copy of the origin is now at each end of the cell.

40. Cell wall Origin of replication Plasma membrane E. coli cell Bacterial chromosome Chromosome replication begins. Soon thereafter, one copy of the origin moves rapidly toward the other end of the cell. Two copies of origin LE 12-11_3 Origin Origin Replication continues. One copy of the origin is now at each end of the cell. Replication finishes. The plasma membrane grows inward, and new cell wall is deposited. Two daughter cells result.

41. A comparison of mitosis and meiosis

42. A comparison of mitosis and meiosis: summary