chromosome 2015

8/18/2019 Chromosome 2015

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Prokaryotic chromosomes

•Circular double helix

•Complexed with protein in a

structure termed the nucleoid

•Attached to plasma

membrane


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Eukaryotic Chromosomes

• Located in the nucleus

• Each chromosome consists of a single molecule of

DNA and its associated proteins

he DNA and protein complex found in eukaryoticchromosomes is called chromatin!"# DNA and $"# protein

•Complex interactions between proteins and nucleic

acids in the chromosomes regulate gene and

chromosomal function


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(1) Kromatid. Salah satu daridua bagian identikkromosom yang terbentuksetelah fase S pada

pembelahan sel.(2) Sentromer. Tempat

persambungan keduakromatid, dan tempatmelekatnya mikrotubulus.

(3) Lengan pendek() Lengan pan!ang.

Kinetokor " tempatpelekatan benang spindle

http://id.wikipedia.org/wiki/Fase_Shttp://id.wikipedia.org/wiki/Fase_S


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A typical mitotic chromosome at

metaphase


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Figure 7-13 Forms of chromotin structure seen in EM(electron microscopy)

Figure 7-13 Forms of chromotin structure seen in EM(electron microscopy)


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• #hromosomes are made of$%&.

• 'ah ontains genes in a

linear order.

• uman body ells ontain *hromosomes in 23 pairs +one of eah pair inheritedfrom eah parent

•

#hromosome pairs 1 + 22are alled autosomes.

• The 23rd pair are alled sehromosomes"-- is female, - is male.

/ene for sikle ell disease(hromosome 11)

/ene for ysti 0brosis

(hromosome )


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pp

#entromere#entromere

#hromosome #hromosome


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(1) Nucleosomes are the

building blocks ofchromosomesT h e

n u cl e

o s om e

The nucleosome is composed ofa core of eight histone proteinsand the DNA (core DNA, 147 bp)wrapped around them The DNAbetween each nucleosome is

called a linker DNA !acheukar"ote has a characteristica#erage linker DNA length ($%&

'% bp)


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Figure 7-18 DNApacage! into

nucleosome

Figure 7-18 DNApacage! into

nucleosome

"i#-fol! DNA compaction


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Nucleosome %tructures

&istone octamer

$ &$A

$ &$'

$

$ &(


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i#e abundant histones are 1 (linker histone, $% kd), $A,

$*, + and 4 (core histones,11&1 kd)

The core histones share a

common structural fold, calledhistone&fold domain

The core histones each ha#e an

N&terminal -tail., the sites of

($) istones are small,positi#el" charged (basic)proteinsT h

e

n u cl e

o s om e


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istone 1 binds to the linkerDNA between nucleosome,

inducing tighter DNAwrapping around thenucleosome

)i gh er & or d e

r ch r om

at i n st

r u c

Figures 7-$8% $&Figures 7-$8% $&


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A model of centromere structure


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Figure 7-' entromeres% origin of replication an!telomere are reuire! for euaryotic chrom* maintenanceFigure 7-' entromeres% origin of replication an!telomere are reuire! for euaryotic chrom* maintenance


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e2uired for the correctsegregation of the chromosomesafter replication

Direct the formation ofkinetochore (an elaborateprotein comple/) essential forchrom segregation

3ne chromosome, onecentromere

The sie #aries ($%% bp& 54% kb)

6entromeres 6 h r om o s om e d u pl i c at i o

n 7

s e gr e g

chromosome 2015

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