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8/12/2019 Medical Genetic II Dna Rna
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Basic Molecular Genetics
Dr. Upik A. Miskad, PhD
Unhas Research Center
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Medical genetics in the past : Minor subject in the school. Related to uncommon diseases. (ex/hemofilia, sindr.down, buta warna) Only specialist and affected patients
concern to the subject.Medical genetics today :
Explain underlying molecularpathobiology of many diseases.
(mjelaskan semua pyk kec lingk) Mainstream of medical science and
public health. Powerful tool to establish: diagnosis,classification, prognosis, prediction ofcomplication, as well as response tothe treatment.(alat utk mnegakkan
diag, etc)
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Dr. Upik A. Miskad, PhD
Unhas Research Center
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CELLS
Cells are the basic units of livingorganisms. Although a nerve cell looksentirely different from a red blood cell, theirorganizations are essentially the same.
Cells (Prokariotik dan eukaryotik)
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Eukaryote versus prokaryote
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Circular shape of microbial DNA
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Cells * building block of all life
* very small : - membrane- cytoplasm : RNA- nucleus
chromosomes
DNA
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An organism may containmany types of somatic cells,each with distinct shape andfunction.
However, they all have thesame genome.
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The genes in a genome do nothave any effect on cellularfunctions until they are"expressed".
Different types of cells expressdifferent sets of genes,thereby exhibiting variousshapes and functions.
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.
The central dogma statesthat once informationhas passed into protein it
cannot get out again.
The transfer of informationfrom nucleic acid to nucleicacid, or from nucleic acid to
protein, may be possible,but transfer from protein toprotein, or from protein tonucleic acid, is impossible.
The information goes only one way
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GENE
By definition, a geneincludes the entire nucleic acid sequencenecessary for the expression of its product (peptide or RNA).Such sequence may be divided into regulatory regionand
transcriptional region.
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ASAM NUKLEATAsam Deoksiribonukleat
DNA(Deoxyribonucleid Acid)
Asam Ribonukleat
RNA(Ribonucleid Acid)
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DNA
DNA adalah suatupolimer yang panjang
tidak bercabang,mengandung 2 rantaipolynucleotida, yangtersusun sebagaisuatu bentukantiparalel yangmengelilingi aksis.
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DNA
DNA tersusun sebagaisuatu right-handed
double helix dengankelompokangula-posfatsebagai tulangpunggungnya danbasabasa tersusundibagian pinggirnya
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Nucleotides (basa):
A - T
G - C
Sugar:
De oxy ribose
(DNA)
Ribose (RNA)
Phosphate:
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DNA
* can be renatured and denatured
* denatured : boils temperature
extreme of PH (PH < 3PH > 10)
* renatured : 650C
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BASES There are five different bases, each is denoted by a
single letter as given in the parenthesis:
Adenine (A), Cytosine (C), Guanine (G), Thymine(T), and Uracil (U).
Among them,
A, C, G and T exist in DNA;
A, C, G and U exist in RNA.
S ti l tid di l h 3 k
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Setiap nucleotidadisusun oleh 3 komponen:
1. Gula/ pentose,
2. Basa/ base
3. Phosphate group.
Nucleosida Disusun oleh gula/ pentosa dan basa saja
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Basa berikatan dengan dengan Deoxyribosadengan Glycocyl linkage(warna ungu)membentuk NUCLEOSIDA.
Gugus gula pada ikatan basa dan gula bilamengalamiphosphorilasi(penambahan gugusphospat) akan mementuk NUCLEOTIDA.
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Phosphodiester bridge Nucleotida dihubungkansatu sama lain oleh jembatan
phosphodiester(Phosphodiester bridge)
Yang menghubungkanantara gula pada nucleotida
yang satu dengan phosphatpada nucleotida yang lainnya
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STRUKTUR KIMIA GULA/ PENTOSA
The chemical structure of pentose which contains five carbon atoms,labeled as C1' to C5'.
The pentose is called ribosein RNA and deoxyribosein DNA, because
the DNA's pentose lacks an oxygen atom at C2'.
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PENTOSA/GULA RNA : RiboNucleid Acid
DNA: DeoxyriboNucleid Acid
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BASA
Ada 2 macam Basa pada Asam nukleat: Purin PirimidinPurin: Struktur kimianya terdiri dari 2 cincin yang
bergandengan
Terdiri dari 2 macam:A: AdenineG: Guanine
Pirimidin: Struktur kimianya terdirihanya 1 cincin.
Terdiri dari 3 macam:C: CystosineT: ThymineU: Urasil
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STRUKTUR KIMIA
BASA
Ada 2 macam Basa pada
Asam nukleat:
1. Purin
2. Pyrimidin
Purin:A: Adenine
G: Guanine
Pirimidin:
C: Cystosine
T: Thymine
U: Urasil
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BASA YANG MEMBENTUK DNAComputer model of base pairing inDNA.
In a normal DNA molecule,Adenine (A) is paired with
Thymine (T),Guanine (G) is paired withCytosine (C).
The uracil (U)of RNA can alsopair with adenine (A), since Udiffers from T by only a methyl
group located on the other side ofhydrogen bonding (ikatanhidrogen)
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FUNGSI BASA DALAM DNA
Utk : Mempertahankan kestabilan DNAdengan adanya ikatan hidrogen antarapasangan pasangan basa dari 2 rantaipolinucleotida dalam arah horisontal.
A DNA molecule has two strands, heldtogether by the hydrogen bondingbetween their bases. As shown in thefigure:
Adenine can form two hydrogenbonds
with Thymine; Cytosine can form three hydrogen
bondswith Guanine.
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RNA (RIBONUCLEID ACID)
Ribonucleid Acid mempunyai strukturkimia yang mirip DNA, kecuali:
1. Gulanya ribosa
2. Basa thymine (T) diganti dengan Uracyl
(U) 3. merupakan single strand (rantai tunggal
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RNA (RIBONUCLEID ACID)
Most cellular RNAmolecules are singlestranded.
They may formsecondary structuressuch as stem-loop and
hairpin.
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Ada 3 macam molekul RNA
1. Messenger RNA (mRNA) RNA yangmengarahkan pembentukan molekul protein.
2. Transfer RNA (tRNA)RNA yang berfungsimembawa Asam Amino ketempatpembentukan protein.
3. Ribosomal RNA (rRNA)RNA yang berfungsimembentuk komponen ribosom.
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RNA (RIBONUCLEID ACID)
Molekul RNA disintesa dari DNA melaluiproses yang disebut DNA Transcription.
Molekul RNA relative lebih pendekdibandingkan dengan DNA karena RNA
dicopy dari satu daerah yang terbatas.
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mRNA Molekul RNA disintesa
dari DNA melalui prosesyang disebut DNATranscription.
mRNA membawainformasi untuk sintesaprotein
Perhatikan tidak ada T
pada RNA, T (thymin)diganti dengan U (Urasil)
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The central dogmaAccording to the process,
the flow of genetic information is in thefollowing direction:
DNA > RNA > Protein.
Essential steps involvedin the expression ofprotein genes
CENTRAL DOGMA
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GENE EXPRESSIONGene expression" means the production of a protein or a functionalRNA from its gene.Several steps are required:
Transcription: A DNA strand is used as the templatetosynthesize a RNA strand, which is called the primary
transcript.RNA processing: This step involves modifications of theprimary transcript to generate a mature mRNA (for proteingenes) or a functional tRNA or rRNA.
For RNA genes (tRNA and rRNA), the expression is completeafter a functional tRNA or rRNA is generated. However, protein
genes require additional steps:Nuclear transport:mRNA has to be transported from the
nucleus to the cytoplasm for protein synthesis.
Protein synthesis: In the cytoplasm, mRNA binds toribosomes, which can synthesize a polypeptide based on thesequence of mRNA.
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PROSES TRANSKRIPSI DNA1.Pengkopian seluruh panjang DNA yang diinginkan
untuk dikopi Meliputi ekson dan intron denganbantuan enzym RNA polymerase membentukprimary transkript
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PROSES TRANSKRIPSI DNA2. Sebelum molekul RNA meninggalkan nukleus,enzym pembentuk Komplex RNA (Complex of RNAprocessing enzyme) akan menghilangkanSemua intron
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PROSES TRANSKRIPSI DNA3. Setelah proses Splicing, RNA yang lebih pendek akan
Bergerak ke sitoplasma, untuk selanjutnya membentukAsam asam amino.
Exon : regio pada RNA yang mempunyaikemampuan mengkode protein
Intron : regio pada RNA yang tidak mempunyaikemampuan menkode Protein
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Tiga nucleotida berturut turut dalam mRNAmenkode satu asam amino atau stop signal untuksintesa protein.
Tiga rangkaian nucleotida ini disebut CODON
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CODON
Adalah suatu sequences yang terdiri dari 3nukleotida yang mengkode satu asamamino spesifik
Jadi seharusnya ada 43=64asam aminodari 4 kombinasi nukleotida yang ada.
Tapi yang hanya ditemukan dalam ptoteinadalah 20 asam amino
Jadi ada beberapa Codon membentukasam amino yang serupa.
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The central dogmaAccording to the process,
the flow of genetic information is in thefollowing direction:
DNA > RNA > Protein.
Essential steps involvedin the expression ofprotein genes
CENTRAL DOGMA
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tRNA
Translasi dari mRNA ke proteintergantung pada adaptor molekulyang disebut tRNA.
tRNA Berfungsi mengenali danmembawa asam amino yang akandibentuk.
Terdiri atas 80 nukleotida
Berbentuk seperti clover leaf
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tRNA
Berbentuk tonjolan 3 dimensi.
Ada 2 daerah yang penting:
1. anticodon: daerah yang disusun oleh 3
nukleotida yang akan berikatan dengankodon komplemennya pada mRNA
2. amino acid attachment region:
daerah pada tRNA yang akan mengikat
asam amino yang dibawanya
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PROSES TRANSLASI PROTEIN
Genetic code:
A process of translating ofthe nucleotide sequenceinto amino acidsequence of protein.
During protein synthesis,the ribosome binds tomRNA and tRNA as
shown in the followingfigure.
Only the tRNA containingthe anticodon whichmatches mRNA's codonmay join the complex
h A ib A l
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Pemesanan molekul tRNA
pada mRNA memerlukan
tempat yang disebut
RIBOSOME
RIBOSOME: adalah suatu
mesin pembentukan protein
yang mengandung tRNA yangakan membaca informasi
genetik pada mRNA
The mRNA-ribosome-tRNA complex
PROSES TRANSLASI PROTEIN
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Ribosome akan bergerak
sepanjang mRNA dan tRNA yangada didalamnya akan membaca
pesan genetik sambil membawa
asam amino yang akan dirangkai
dengan asam amino yang lain
membentuk polipeptida.
PROSES TRANSLASI PROTEIN
pada mRNA-ribosome-tRNA complex
Polipeptida
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PROTEIN Protein dibentuk oleh rangkain polipeptida dan
polipeptida disusun oleh asam amino.
Asam asam amino dihubungkan satu sama laindengan ikatan peptida.
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See you in the next lecture
Thank you