SHPTEuka Genom Fixed

8/3/2019 SHPTEuka Genom Fixed

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GENE - GENOMEMot so khai niem can biet :

- Genome Genomics - Genetics

- Gene/allele/locus

- CpG islands

- Genetic linkage

- Reading frame/Open Reading Frame (ORF)

- Transcriptome

- Proteome- Pseudogene

- Chromatin/chromosome

- Hetero/euchromatin

CHUOI XOAN KEP DNA

Mot so tnh chat cua phan t DNA :

oi song song

Chieu 5P -3OH

Cau truc on nh phan ln nh s xep chong cac base (base stacking)


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RNATnh linh ong hoa hoc do C2OH

Hnh thanh cau truc th cap

CAU TRUC NHIEM SAC THE EUKARYOTE


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MOT SO TNH CHAT

VAT LY CUA DNA

TNH DI ONG IEN DI CUA DNA


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Bo gene eukaryote

Tai sao eukaryote co mang nhan ?

V sao DNA eukaryote c nen lai ?

Nen nh the nao ?

KCH THC DNA/GII HAN KHONG GIAN

Chieu dai phan t DNA, ac biet phan ln eukaryote, vt xa kch thcnhan can co s nen mot cach trat t


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CAU TRUC BO GENE

GENOME CONTENT

Genome size is related to the complexity of the organism because a complex organismmay need more genes participating in the formation of different parts of its organism.

Genome size : 0.58 Mb (1Mb = 1.106 nucleotides) 6.7 Mb in prokaryotes ; 12 Mb 12,000 Mb in eukaryotes.

Number of genes : about 500 6,000 genes in prokaryotes ; about 6,000 - 45,000 genes ineukaryotes.

Nevertheless, the correlation between genome size/number of genes with the structuralcomplexity of an organism is not perfect ; e.g in human there are 27,000 genes whereas

maize has > 45,000 genes

The different ratio of the number of genes/ genome size between prokaryotes andeukaryotes is due to the fact that prokaryotic genome is nearly entirely composed of codingsequences (genes) whereas eukaryotic genomes contain a very small percentage of codingsequences (about 1%) with the remaining constituted of non-coding sequences.

Gene density : number of genes / genome size (genes/Mb) ratioOrganisms with increasing structural complexity usually have decreasing gene density ;

e.g gene density inE. coli(prokaryote), S. cerevisiae (unicellular eukaryote) and human(eukaryote) is respectively 950, 480 and 9.3.


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OPEN READING FRAME

CAU TRUC BO GENE NGI


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KCH THC EXON & INTRON

MOT SO AC IEM CAU TRUC BO GENE EUKARYOTE


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CAU TRUC VAT LIEU DI TRUYEN EUKARYOTE

Cac mc o nen :

DNA Nucleosome Si 30-nm Si 30-nm lien ket vi khung Nhiem sac chatNhiem sac the trung ky (metaphase)


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CHROMATIN, CHROMOSOME

In the cell, the DNA-protein complex is called chromatin. Depending on the degree of compaction,chromatin can be classified as euchromatin or heterochromatin, named on their degree of staining withbasic dyes - slightly (euchromatin) or darkly (heterochromatin).

Most part of chromatin is euchromatin. Euchromatin is much more less compacted than heterochromatinand is the genetically active part of the genome, mainly composed of actively transcribed genes. Constitutiveheterochromatin is essentially located at the telomeres and centromeres, some is dispersed all over thechromosomes.This dispersed heterochromatin is mostly composed of repetitive sequences. Non-constitutiveheterochromatin originates from temporally non transcribed euchromatin.

The genome of prokaryote usually exists as a single DNA molecule whereas eukaryotic genome isdistributed into many DNA molecules ; each DNA molecule associated with its proteins is called achromosome.

The role of associated proteins is to compact DNA molecule in order to :1. Make long DNA molecule fitted in a small space which is the cell (prokaryote), or the nucleus

(eukaryote).E. colichromosome measuring 1 mm must fit in a 1 m-length cell. In human, a haploidchromosome set is constituted of 3.109 bp a diploid set has 2 x 3.109 bp, each bp has a thickness of 3.4 (1= 1

-10

m) in a somatic cell, the nucleus contains a 2m-length DNA !2. Protect the long DNA molecule from damages.

3. Facilitate the replication and the recombination of DNA as a whole entity during cell division.

4. Facilitate gene expression through selectively decompacting individual regions in the genome.

The majority of eukaryotic cells are diploid, which means that they contain 2 copies of each chromosome,each coming from one parent. Haploid cells (egg or spermatozoid) are those containing only one set of eachchromosome.

NUCLEOSOME


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CAC BAC NEN CUA NST

Nucleosome core + H1 = Chromatosome

Vai tro cua H1 : on nh ni DNA vao va rakhoi nucleosome

Cau truc cua si30-nm

CAC BAC NEN CUA NST


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S NEN NST VA BIEU HIEN GENE

D nhiem sac chat tuy y(facultative) : the Barr sbat hoat X (s Lyon hoa)

D nhiem sac chat bat buoc (constitutive) : thng centromere va telomere, cha DNA satellite, co vai tro trongieu hoa bieu hien gene va on nh cau truc NST

ong nhiem sac chat : batmau nhuom t, la cac v tr

phien ma manh

S NEN NST VAPHAN BAO


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CAU HOI CHNG 2

1. Cac th nghiem chng minh DNA la vat l ieu di truyen cua vi khuan, virus,ong vat

2. Tnh on nh cau truc cua DNA co nguyen nhan t au ?

3. Mat o gene thap eukaryote la do au ?

4. Y ngha cua cau truc NST va viec duy tr on nh thong tin di truyen ?

5. Cac yeu cau de am bao tnh on nh cua NST dang vong va NST dangthang ?

CAU HOI CHUAN B :

Cac van e at ra oi vi s sao chep DNA eukaryote

SEMINAR 1. Qua trnh sao chep DNA E. colikhi phan chia te bao

2. Cac bien oi cua DNA trong qua trnh song cua E. coli

3. Cac bien phap gi on nh phan t DNA

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SHPTEuka Genom Fixed