Siklus Sel (STF)

7/30/2019 Siklus Sel (STF)

1/42

SIKLUS SEL

Suryana, S.Si. MP.


2/42

Figure 12.1

Kontinuitas kehidupanDidasarkan atas reproduksi sel atau pembelahan sel


3/42

100 m

(a) Reproduction. An amoeba,

a single-celled eukaryote, isdividing into two cells. Eachnew cell will be an individualorganism (LM).


4/42

Organisme multiseluler tergantung pada pembelahansel untuk:

Perkembangan (dari sel yang terfertilisasi)Pertumbuhan

Repair

20 m200 m

(b) Growth and development.This micrograph shows asand dollar embryo shortlyafter the fertilized egg divided,forming two cells (LM).

(c) Tissue renewal. These dividingbone marrow cells (arrow) willgive rise to new blood cells (LM).

Figure 12.2 B, C


5/42

Semua organisme kompleks

berasal dari a single fertilizedegg.

Melalui pembelahan sel, jumlah sel meningkat

Sel kemudian terspesialisasidan berubah menjadifungsinya masing2


6/42

Tipe pembelahan selMitosis:

Growth, development & repairAsexual reproduction (yields identical cells)Occurs in somatic (body) cells

Meiosis:Sexual reproduction (yields different cells)Occurs in specific reproductive cells


7/42

Phases of Mitosis

1. Prophase2. Prometaphase3. Metaphase4. Anaphase

5. Telophase

Pembelahan sel menghasilkan sel anak yangsecara genetik identik

Sel harus menduplikasikan material genetiknya Before they divide, ensuring that each daughter cell

receives an exact copy of the genetic material, DNA


8/42

Distribution of Chromosomes DuringCell Division

Pada persiapan cell division, DNA bereplikasi dankromosom memadatTiap chromosome yang terduplikasi memiliki duasister chromatids, yang berpisah selama cell divisionSentromer merupakan daerah ceking darichromosome yang terduplikasi, diaman duachromatids terikat dengan dekat


9/42

Figure 12.1

prophase

1X

metahase

Anaphase

Telophase

Cytokinesis


10/42

Cell division results in genetically identicaldaughter cells

Sel menduplikasikan material genetik sebelummembelah, utk memastikan bahwa tiap sel anakmenerima copy DNA dengan tepat

A cells endowment of DNA (its geneticinformation) is called its genome

Molekul DNA dalam sel ter-pack menjadikromosom


11/42

Setiap spesies eukariot memiliki sejumlah tertentukromosom pada nukleusSel somatik (nonreproductive) memiliki 2 setkromosom

Gamet (reproductive cells: sperm and eggs) memiliki jumlah kromosom setengah jumlah kromosom selsomatikKromosom eukaryotik terdiri dari kromatin, sebuah

komplex DNA dan protein yang memampat selamapembelahan sel


12/42


13/42

0.5 m

Chromosomeduplication(including DNAsynthesis)

Centromere

Separation

of sisterchromatids

Sisterchromatids

CentromeresSister chromatids

A eukaryotic cell has multiplechromosomes, one of which is

represented here. Beforeduplication, each chromosome

has a single DNA molecule .

Once duplicated, a chromosomeconsists of two sister chromatids

connected at the centromere. Each

chromatid contains a copy of theDNA molecule .

Mechanical processes separatethe sister chromatids into twochromosomes and distribute

them to two daughter cells .

Figure 12.4


14/42


15/42

Pada pembelahan sel, fase mitosis bergantiandengan interfase

Pada tahun 1882, ahli anatomi Jerman Walther Flemming mengembangkan pewarna untuk

mengamati kromosom selama mitosis dansitokinesisBagi Flemming, terlihat sel tumbuh membesar Sekarang dapat diketahui banyak peristiwa kritisterjadi selama tahapan siklus sel


16/42


17/42

Fase-fase dalam siklus selSiklus sel terdiri dari

Fase mitosisInterphase

INTERPHASE

G1 S(DNA synthesis)

G2

Figure 12.5

Interphase G 1 phase S phase G 2 phase

The mitotic phase mitosis cytokinesis


18/42


19/42

Mitosis terdiri dari 5 phasesProphasePrometaphase

G2 OF INTERPHASE PROPHASE PROMETAPHASE

Centrosomes(with centriole pairs) Chromatin

(duplicated)

Early mitoticspindle

Aster

CentromereFragmentsof nuclearenvelope

Kinetochore

Nucleolus Nuclear

envelope

Plasma

membrane

Chromosome, consistingof two sister chromatids

KinetochoremicrotubuleFigure 12.6

Nonkinetochoremicrotubules


20/42

Metaphase AnaphaseTelophase

Centrosome atone spindle pole

Daughterchromosomes

METAPHASE ANAPHASE TELOPHASE AND CYTOKINESIS

Spindle

Metaphaseplate Nucleolus

forming

Cleavagefurrow

Nuclearenvelopeforming

Figure 12.6


21/42

The mitotic spindle mikrotubul yang mengontrol pergerakan kromosom

selama mitosis

Spindle muncul dari sentromer spindle microtubules

asters


22/42

Perakitan spindle microtubules dimulai dari sentrosom- microtubule organizing center Sentrosom bereplikasi membentuk dua sentrosomyang bermigrasi ke kutub yang berlawanan, danspindle microtubules tumbuh dari sentrosom

Aster (a radial array of short microtubules) muncul daritiap sentrosom


23/42

The Spindle

Spindle memiliki struktur seperti web terbuat darimicrotubule . Sangat penting pada mitosis karenamengatur kromosom untuk berada pada posisi yangbenar

Mitotic center

Microtubule A cell at metaphase a spindle

S i dl i b l


24/42

Some spindle microtubulesBerikatan dengan kinetochores chromosomes

CentrosomeAster

Sisterchromatids

MetaphasePlate

Kinetochores

Overlappingnonkinetochoremicrotubules

Kinetochores microtubules

Centrosome

ChromosomesMicrotubules0.5 m

1 mFigure 12.7


25/42

Chromosomes attached to spindleduring nuclear division

T ki d f i t b l


26/42

Two kinds of microtubulesKinetochore microtubules : berikatan dengan

kinetochores chromosomes dan menggerakkan kromosom ke

daerah metafaseNonkinetochores: overlap satu sama lain tetapi tidak

berikatan dengan chromosome

1 m


27/42


28/42

Pada anafase, sister chromatid berpisahDan bergerak sepanjang kinetochore microtubulesmenuju arah berlawanan ujung sel

Spindlepole

Kinetochore

Figure 12.8


29/42

Initiation of Anaphase


30/42

Nonkinetechore microtubules fromopposite poles

Overlap and push against eachother, elongating the cell

In telophaseGenetically identical daughter nuclei form at opposite ends of thecell

The microtubules shorten by depolymerizing attheir kinetochore ends


31/42


32/42


33/42

Pada sel hewanCytokinesis terjadi oleh proses yang disebut cleavage,membentuk sebuah a cleavage furrow

Cleavage furrow

Contractile ring of microfilaments

Daughter cells

100 m

(a) Cleavage of an animal cell (SEM)


34/42

Pada sel tumbuhan, selama cytokinesisTerbentuk plat sel (cell plate)

Daughter cells

1 mVesiclesformingcell plate

Wall of patent cell Cell plate New cell wall

(b) Cell plate formation in a plant cell (SEM)Figure 12.9 B


35/42


36/42

Purpose of Interphase to duplicate cell contents;90% of the cells growth cycle

Purpose of Mitosis to divide the genetic materialinto exact two halves

Purpose of Cytokinesis to divide all other contents

(except nucleus) into two cells


37/42

In binary fission The bacterial chromosomereplicates

The two daughter chromosomes actively moveapart

Prokaryotes (bacteria andarchaea) reproduce by a type

of cell division called binaryfission

LE 12-11_1


38/42

Origin of replication

Cell wall

Plasmamembrane

Bacterialchromosome

E. coli cell

Two copiesof origin

Chromosome replicationbegins. Soon thereafter,one copy of the originmoves rapidly toward theother end of the cell.

LE 12-11_2


39/42

Origin of replication

Cell wall

Plasma

membraneBacterialchromosome

E. coli cell

Two copiesof origin

Chromosome replicationbegins. Soon thereafter,one copy of the origin

moves rapidly toward theother end of the cell.

Replication continues. Onecopy of the origin is now ateach end of the cell.

Origin Origin


40/42

A comparison of mitosis and meiosis


41/42

A comparison of mitosis and meiosis

A comparison of mitosis and meiosis: summary


42/42

A comparison of mitosis and meiosis: summary

Siklus Sel (STF)

Documents