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Dogma sentral

dalam Biologi

Mirfat

Bagian Anatomi-Biologi FKUY

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Dogma Sentral Biologi

Sumber seluruh informasi biologi

Dalam dogma tersebut terlihat peran DNA dan RNA dalam sintesis protein

3 hometestingblog.testcountry.com/?p=497

Aliran informasi genetik

DNA

RNA

protein

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The pathway from DNA to

protein

The flow of genetic information from DNA to RNA (transcription) and from RNA to protein (translation) occurs in all living cells.

From: Chapter 6, How Cells Read the Genome: From DNA to Protein. Molecular Biology of the Cell. 4th edition. Alberts B, Johnson A, Lewis J, et al. New York: Garland Science; 2002.

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Genes can be expressed with

different efficiencies

Gene A is transcribed and translated much more efficiently than gene B. This allows the amount of protein A in the cell to be much greater than that of protein B.

From: Chapter 6, How Cells Read the Genome: From DNA to Protein. Molecular Biology of the Cell. 4th edition. Alberts B, Johnson A, Lewis J, et al. New York: Garland Science; 2002.

Mengapa sintesis protein penting?

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Figure 5-2 Molecular Biology of the Cell ( Garland Science 2008)

MOLECULAR BIOLOGY DNA replication, transcription

REPLICATION FORK

1000 nt / sec !

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Model Replikasi DNA

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Replication

10 http://serc.carleton.edu/images/microbelife/microbservatories/methods/replication.v3.jpg

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replication direction

3

3

5

5

3

leading strand

3 5

5 5

3 lagging strand

with Okazaki

fragments

DNA polymerase synthesizes in 5 3 direction

MOLECULAR BIOLOGY DNA replication, transcription

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Transkripsi

Sintesis RNA yang menggunakan cetakan DNA

Transkripsi

Enzim yang bertanggungjawab terhadap transkipsi : RNA polimerase, yang

bergerak di sepanjang gen dari

promoternya sampai di belakang

terminator

Menyusun RNA dg urutan nukleotida yg berkomplementer dg untai cetakan gen

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14 http://archive.gersteinlab.org/mark/site/Images-for-talks/FORPPT--I-RIC-from--kvhs-nbed-nb-ca--transcription

Tahapan transkripsi

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Tahapan transkripsi

1. Setelah RNA polimerase berikatan ke promoter, untai-untai DNA membuka, dan polimerase menginisiasi sintesis RNA di titik mulai pada untai cetakan

2. Polimerase bergerak, membuka DNA dan memperpanjang transkrip RNA 5 3. Setelah transkripsi, untai-untai DNA kembali membentuk heliks ganda

3. Transkrip RNA dilepaskan, polimerae melepaskan diri dari DNA

Translasi

Sel menerjemahkan pesan genetik dan membangun polipeptida sesuai pesan tsb

Pesan : serangkaian kodon di sepanjang mRNA

Sang penerjemah: RNA transfer: mentransfer asam amino dari kumpulan

asam amino di sitoplasma ke ribosom

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mRNA is

transported out of

nucleus. In

citoplasm,

ribosomal subunits

bind to mRNA

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tRNA molecules become attached

to specific amino

acids with the

help of activating

enzymes. Amino

acids are brought

to the ribosome

in the order

directed by

mRNA http://www.scq.ubc.ca/changing-the-language-of-dna/

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tRNAs bring their amino acids in at A

site on the ribosome.

Peptide bonds form

between amino acids

at the P site, & tRNA

exit the ribosome

from the E site

Polypeptide chain grows until the

protein completed

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Terminasi translasi

http://images.google.co.id/imgres?imgurl=http://kvhs.nbed.nb.ca/gallant/biology/translation.jpg&imgrefurl

Ribosom sub unit

kecil dan besar

akan terpisah dan

meninggalkan

mRNA.

Ribosom

mencapai kodon

terminasi pada

mRNA, tempat A

menerima faktor

pelepas ganti

tRNA

Faktor pelepas

menghidrolisis ikatan

antara tRNA dalam

tempat P & asam

amino terakhir & rantai

polipeptida

Figure A.6. Gene Transcription, Translation, and Protein Synthesis.

stemcells.nih.gov/info/scireport/appendixA.asp

Sintesis protein pada prokariot dan eukariot

Pada sel bakteri yang tidak memiliki nukleus, mRNA yang dihasilkan oleh transkripsi langsung

ditranslasi tanpa pemrosesan lebh lanjut

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Kode triplet

http://www.uic.edu/classes/bios/bios100/lectures/cen

traldogma.jpg

Selama translasi urutan

kodon di mRNA dikode

menjadi urutan asam

amino yang menyusun

polipeptida

Selama translasi pesan

genetik (mRNA) dibaca

sebagai triplet (kodon)

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Kamus kode genetik

http://www.google.co.id/imgres?imgurl=http://members.cox.net/amgough/gene_exon_intron-01_01_10.jpg&imgrefurl=

http://members.cox.net/amgough/Fanconi-genetics-genetics-primer.htm&h=240&w=460&sz=62&tbnid=

_JLhHP0Z7HQN4M:&tbnh=67&tbnw=128&prev=/images%3Fq%3Dexon%2Bintron%2Bimages&usg=

__-n5sOzAC3iacsI4-J6eQg12ol_I=&ei=ymZlSvyOGI3W6gP_sPQb&sa=X&oi=image_result&resnum=2&ct=image

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DAFTAR ACUAN

Alberts. B. et. al. 2009. Molecular

Biology of The Cell. Fourth edition.

Garland Science Taylor & Francis

Group

Brown,T. A. 2002. Genomes. Second Edition. BIOS Scientific Publishers Ltd

Campbell, Reece-Mitchel. 2002. Biology. Edisi Kelima-jilid 1 Penerbit

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