Presentasi sedang didownload. Silahkan tunggu

Presentasi sedang didownload. Silahkan tunggu

SIKLUS SEL Made Pharmawati. Figure 12.1 Kontinuitas kehidupan Didasarkan atas reproduksi sel atau pembelahan sel.

Presentasi serupa


Presentasi berjudul: "SIKLUS SEL Made Pharmawati. Figure 12.1 Kontinuitas kehidupan Didasarkan atas reproduksi sel atau pembelahan sel."— Transcript presentasi:

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 Organisme multiseluler tergantung pada pembelahan sel untuk: – Perkembangan (dari sel yang terfertilisasi) – Pertumbuhan – Repair 20 µm200 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

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 Pada persiapan cell division, DNA bereplikasi dan kromosom memadat Tiap chromosome yang terduplikasi memiliki dua sister chromatids, yang berpisah selama cell division Sentromer merupakan daerah ceking dari chromosome yang terduplikasi, diaman dua chromatids terikat dengan dekat

9 Figure 12.1 prophase 1X metahase Anaphase Telophase Cytokinesis

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 Setiap spesies eukariot memiliki sejumlah tertentu kromosom pada nukleus Sel somatik (nonreproductive) memiliki 2 set kromosom Gamet (reproductive cells: sperm and eggs) memiliki jumlah kromosom setengah jumlah kromosom sel somatik Kromosom eukaryotik terdiri dari kromatin, sebuah komplex DNA dan protein yang memampat selama pembelahan sel

12

13 0.5 µm Chromosome duplication (including DNA synthesis) Centromere Separation of sister chromatids Sister chromatids Centromeres Sister chromatids A eukaryotic cell has multiple chromosomes, one of which is represented here. Before duplication, each chromosome has a single DNA molecule. Once duplicated, a chromosome consists of two sister chromatids connected at the centromere. Each chromatid contains a copy of the DNA molecule. Mechanical processes separate the sister chromatids into two chromosomes and distribute them to two daughter cells. 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

16

17 Fase-fase dalam siklus sel Siklus sel terdiri dari – Fase mitosis – Interphase INTERPHASE G1G1 S (DNA synthesis) G2G2 Cytokinesis Mitosis MITOTIC (M) PHASE Figure 12.5 Interphase – G 1 phase – S phase – G 2 phase The mitotic phase – mitosis – cytokinesis

18 Phases of the Cell Cycle Siklus sel terdiri dari – Mitotic (M) phase (mitosis and cytokinesis) – Interphase (cell growth and copying of chromosomes in preparation for cell division) Interphase (terdiri dari sekitar 90% dari siklus sel) yang dapat dibagi dalam sub fase: – G 1 phase (“first gap”) – S phase (“synthesis”) – G 2 phase (“second gap”)

19 Mitosis terdiri dari 5 phases – Prophase – Prometaphase G 2 OF INTERPHASE PROPHASE PROMETAPHASE Centrosomes (with centriole pairs) Chromatin (duplicated) Early mitotic spindle Aster Centromere Fragments of nuclear envelope Kinetochore Nucleolus Nuclear envelope Plasma membrane Chromosome, consisting of two sister chromatids Kinetochore microtubule Figure 12.6 Nonkinetochore microtubules

20 – Metaphase – Anaphase – Telophase Centrosome at one spindle pole Daughter chromosomes METAPHASEANAPHASETELOPHASE AND CYTOKINESIS Spindle Metaphase plate Nucleolus forming Cleavage furrow Nuclear envelope forming Figure 12.6

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

22 Perakitan spindle microtubules dimulai dari sentrosom - microtubule organizing center Sentrosom bereplikasi membentuk dua sentrosom yang bermigrasi ke kutub yang berlawanan, dan spindle microtubules tumbuh dari sentrosom Aster (a radial array of short microtubules) muncul dari tiap sentrosom

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 Microtubule A cell at metaphase a spindle

24 Some spindle microtubules – Berikatan dengan kinetochores chromosomes CentrosomeAster Sister chromatids Metaphase Plate Kinetochores Overlapping nonkinetochore microtubules Kinetochores microtubules Centrosome Chromosomes Microtubules 0.5 µm 1 µm Figure 12.7

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

27

28 Pada anafase, sister chromatid berpisah – Dan bergerak sepanjang kinetochore microtubules menuju arah berlawanan ujung sel Spindle pole Kinetochore Figure 12.8

29 Initiation of Anaphase

30 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 The microtubules shorten by depolymerizing at their kinetochore ends

31

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

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

35 Mitosis in a plant cell 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. Prometaphase. We now see discrete chromosomes; each consists of two identical sister chromatids. Later in prometaphase, the nuclear envelop will fragment. Metaphase. The spindle is complete, and the chromosomes, attached to microtubules at their kinetochores, are all at the metaphase plate. Anaphase. The chromatids of each chromosome have separated, and the daughter chromosomes are moving to the ends of cell as their kinetochore microtubles shorten. Telophase. Daughter nuclei are forming. Meanwhile, cytokinesis has started: The cell plate, which will divided the cytoplasm in two, is growing toward the perimeter of the parent cell Nucleus Nucleolus Chromosome Chromatine condensing Figure 12.10

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

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

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

40 LE 12-11_3 Origin of replication Cell wall Plasma membrane Bacterial chromosome E. coli cell Two copies of origin Chromosome replication begins. Soon thereafter, one copy of the origin moves rapidly toward the other end of the cell. Replication continues. One copy of the origin is now at each end of the cell. Origin 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


Download ppt "SIKLUS SEL Made Pharmawati. Figure 12.1 Kontinuitas kehidupan Didasarkan atas reproduksi sel atau pembelahan sel."

Presentasi serupa


Iklan oleh Google