02 sel rerproduksi

REPRODUKSI SELREPRODUKSI SEL

MITOSIS → sel somatikMITOSIS → sel somatik MEIOSIS → sel seks atau gamet MEIOSIS → sel seks atau gamet

(spermatozoa dan ovum)(spermatozoa dan ovum)Pada umumnya, setiap sel punya 2 periode dlm siklus hidupnya :

1. Periode Interfase

2. Periode Pembelahan

Siklus sel tsb berulang-ulang setiap generasi tetapi tidak sama waktu yang dibutuhkannya

Beberapa sel mempunyai waktu siklus hidup yg pendek serta periode mitosis yg diulang-ulang, sedangkan beberapa sel punya periode interfase sangat panjang bahkan selama hidup organisme tsb

Periode InterfaseTerbagi atas beberapa tahap

1. G-1: memerlukan waktu lama (bervariasi-jam, bln, thn)terjadi sintesis protein & RNA

2. S : umumnya berlangsung antara 7 – 8 jamtjd sintesis DNA, RNA, protein histon

3. G-2 : umumnya berlangsung antara 2 – 5 jamtjd sintesis RNA

Periode MitosisUntuk proses mitosis sendiri, hanya membutuhkan waktu 1 jamTdr atas tahap : Profase, Metafase, Anafase, dan Telofase

MITOSISMITOSIS

Profase Waktunya terpanjang di antara yg lain Sentriole tampak spt 2 titik (Diplosom), sedangkan sitoplasma

sktr diplosom dsbt Sentrosome : pd tahap ini tiap pasang sentriole bergerak ke kutub masing-masing

Mulai terbentuk : Continous microtubuli, bertugas membentuk spindle

Selaput inti pecah shg tak ada lagi pembatas antara kromosom – sitoplasma

Nukleolus menghilang – muncul kromosom

Metafase Terbentuk Chromosomal mikrotubuli, yang memanjang dari

sentromer Sentromer kromosom tepat di bidang ekuator, dgn arah lengan

kromosom ke arah kutub

Anafase Sentromer membelah shg terbentuk 2 kromatid yg

terpisah, & setiap kromatid akan bergerak menuju kutub Pergerakan kromatid diduga karena tarikan

Chromosomal fiber yg memendek disertai pemanjangan Continous fiber

Telofase Ditandai dgn munculnya selubung inti serta nukleolus Kromosom menghilang – butir kromatin Tjd Sitokinesis karena pengerutan sitoplasma di daerah

ekuator – tjd distribusi komponen yang ada dalam sitoplasma

Continous fibers yg tersisa membentuk mid-body di antara 2 sel anak

Mitosis pada sel Mitosis pada sel tumbuhantumbuhan

MeiosisMeiosis 2 divisions 2 divisions Preceded by DNA replicationPreceded by DNA replication 1st Division process1st Division process

divides homologous chromosomesdivides homologous chromosomes 2nd Division process2nd Division process

divides sister chromatidsdivides sister chromatids Produces Gametes with 1 chromosome of each type Produces Gametes with 1 chromosome of each type

PROPHASE IPROPHASE I

SYNAPSIS SYNAPSIS - the pairing and - the pairing and bonding together of bonding together of homologous homologous chromosomes to chromosomes to form form tetradstetrads

Homologous chromosomes Homologous chromosomes consist of oneconsist of one maternal maternal and and one one paternal paternal chromosomechromosome CROSSING-OVERCROSSING-OVER:: Exchange of chromatid Exchange of chromatid

segments within tetrads to segments within tetrads to produce new allele produce new allele combinationscombinations

Nonsisters cross over, break, Nonsisters cross over, break, and rejoinand rejoin

Increases genetic varietyIncreases genetic varietyVIEW OF NUCLEUSAND TETRADS

METAPHASE IMETAPHASE I Tetrads line up in the middle Tetrads line up in the middle

of the cell in a straight line at of the cell in a straight line at equatorequator

Spindle fibers attach to only 1 Spindle fibers attach to only 1 kinetochore of each kinetochore of each centromerecentromere

ANAPHASE IANAPHASE I Tetrads are separated as Tetrads are separated as

homologous chromosomes homologous chromosomes are pulled to opposite poles of are pulled to opposite poles of the cellthe cell

(Remember: the (Remember: the chromosomes are still actually chromosomes are still actually sister chromatids)sister chromatids)

TELOPHASE ITELOPHASE I

Cytokinesis may occur and Cytokinesis may occur and two HAPLOID cells two HAPLOID cells containing sister chromatids containing sister chromatids are producedare produced

A brief period of interkinesis A brief period of interkinesis occursoccurs

INTERKINESISINTERKINESIS

PROPHASE IIPROPHASE II Nuclear membranes disappearNuclear membranes disappear Nucleoli disappearNucleoli disappear Spindle fibers formSpindle fibers form Chromatin coils to form Chromatin coils to form

chromosomeschromosomes

METAPHASE IIMETAPHASE II ANAPHASE IIANAPHASE II

TELOPHASE IITELOPHASE II

GAMETOGENESISGAMETOGENESIS

SPERMATOGENESISSPERMATOGENESIS

STRUKTUR SPERMATOZOA

SPERMATOZOA

TESTIS

* ORGAN PRIMER REPRODUKSI JANTAN

•2 FUNGSI UTAMA :

• PRODUKSI GAMET JANTAN (SPERMATOZOA)

• ENDOKRIN (HORMON SEX, TESTOSTERON)

* SEL GERMINAL TERLETAK DI TUBULUS SEMINIFERUS, MEMBELAH → SPERMATOZOA BARU

* LETAK : DEKAT GINJAL

* PELINDUNG : SKROTUM

OogenesisOogenesis

ORGAN REPRODUKSI BETINAORGAN REPRODUKSI BETINA

*ovarium

*tuba falopii (oviduct, infundibulum)

*uterus

*serviks

*vagina

*vulva

Pada prinsipnya saluran reproduksi betina semua hewan sama, yang membedakan adalah bentuk uterus dan serviks

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