100215555 Cell Division Ppt

8/21/2019 100215555 Cell Division Ppt

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CELL DIVISION

CHAPTER 5



Significance of mitosis

Growth- allows a zygote to produce ore

cell !" order to grow

Repair and replacement- allow t#e

ult!cellular orga"!s a!"ta!" !ts t!ssues$

e%aple s&!" cells a"d 'lood

Asexual reproduction- clo"e



Somatic cells #a(e )

sets o* c#roosoes+

co"ta!"s a d!plo!d

"u'er o*

c#roosoes ,)"-.

/ set !"#er!ted *roeac# pare"t

Human+ #a(e )0 pa!rs

o* c#roosoe.

2n = 46

Hoologous c#roosoes



Cell Cycle

Cell cycle 1 T#e per!odt#at e%te"ds *ro t#et!e a "ew cell !sproduced u"t!l t#e t!et#e cell copletes a cell

d!(!s!o". Mitosis+ "uclear d!(!s!o" !to"inesis+ cytoplas!c

d!(!s!o"

T#e cell cycle !s d!(!ded!"to two a2or p#ases+

#$ %nterphase2$ Mitosis

Cell grows

Cell prepares to d!(!de



I"terp#ase

T#e per!od 'etwee" d!(!s!o"$ d!(!ded !"to 0su' p#ases ,3/$ S a"d 3)-+

!.3/1 cells grow rap!dly a"d "ew orga"elleare sy"t#es!s

!!.S 1 sy"t#es!s o* DNA a"d c#roosoes

are repl!cated!!!.3) 1 cells prepare *or !tos!s$ sy"t#es!sprote!" a"d !tot!c sp!"dle 'eg!" to *or



4!tos!s

4!tos!s !s a d!(!s!o" o* t#e "ucleus to producetwo "ew daug#ter cells co"ta!"!"gc#roosoes !de"t!cal to t#e pare"t cell.

4!tos!s !s a co"t!"uous process a"d d!(!ded!"to a!" p#ases 'ased o" t#e appeara"cea"d 'e#a(!or o* t#e c#roosoes.

/. Prop#ase$ P

). 4etap#ase$ 40. A"ap#ase$ A

. Telop#ase$ T



Prop#ase

&arl! prophase C#roosoe co"de"se a"d appear

s#orter a"d t#!c&er a"d 'ecoe (!s!'le!" a l!g#t !croscope

Eac# c#roosoe "ow co"s!sts o* apa!r o* sister chromatids 2o!"edtoget#er at centromere.

Nucleolus d!sappears 6 "ucleare'ra"e d!s!"tegrates.

Pa!red ce"tr!oles o(e to oppos!tee"ds o* t#e cell

'ate prophase Nuclear e'ra"e d!sappears Sp!"dle *or

Ce"tr!oles

Ce"troere



4etap#ase

Sp!"dle *!'res are *ully*or

S!ster croat!ds l!"e up at

t#e sp!"dle e7uator8etap#ase plate. Two s!ster c#roat!ds are

st!ll attac#ed to o"ea"ot#er at t#e

ce"troere. At t#e e"d o* etap#ase$

t#e ce"troers d!(!de.



A"ap#ase

A"ap#ase 'eg!" w!t# t#eseparat!o" o* t#e ce"troers

T#e s!ster croat!ds are draw"to oppos!te poles o* t#e cell 'ys#orte"!"g o* sp!"dle *!'res.

O"ce separated$ c#roat!dsare re*erred to as daughterchromosome$

E"d a"ap#ase+ t#e poles o*

t#e cell #a(e coplete a"de7u!(ale"t sets o*c#roosoe.



Telop#ase

Telop#ase 'eg!" w#e" t#e twosets o* daug#ter c#roosoes#a(e reac#ed t#e two poles o* t#ecell.

T#e sp!"dle *!'res d!s!"tegrate$ t#e"uclear e'ra"e *ors arou"deac# set o* daug#terc#roosoes a"d t#e "ucleol!reappear.

T#e "ucleolus also re1*ors !"eac# "ucleus.

T#e c#roosoes u"co!l a"d'ecoe less (!s!'le u"der t#e l!g#t!croscope.

4!tos!s process !s "ow copleted.



Cyto&!"es!s

process of c!toplasmic di(isionto form two daughter cells$

D!**ere"t !" a"!als a"d pla"ts. A"!al cells$ t#e cytoplas

co"tracts to pull t#e plasae'ra"e !"wards$ *or!"g groo(ecalled a clea(age *urrow

I" pla"t cells$ cyto&!"es!s !" cells !sar&edly d!**ere"t.

A clea(age *urrow does "ot *or.

I"stead$ e'ra"e1e"closed(es!cle gat#er at a pla"t cell9se7uator 'etwee" t#e two "ucle!.

Ves!cle *use to *or a cell plate



T#e !porta"ce o* co"trolled

!tos!s ontrolled mitosis+ t#e a'!l!ty o* t#e cell to d!(!de at

!ts ow" rate a"d t!e.

Cruc!al to "oral growt#$ de(elope"t a"da!"te"a"ce *or t#e perpetu!ty o* l!(!"g t#!"gs.

Eg+ !" plants co"trolled !tos!s occurs at s#oots

results !" growt# o* pla"ts.

!" #ua" 4alp#!g!a" layer o* s&!" d!(!des act!(ely toreplace dead a"d daaged cells.



T#e e**ects o* u"co"trolled !tos!s

!" l!(!"g t#!"gs

4utat!o" !s t#e c#a"ge !" t#e DNA structure o*

t#e cell.

T#!s c#a"ge !" t#e DNA corrupts t#e codedge"et!c !"struct!o"s *or !tos!s co"trol.

T#!s leads to u"co"trolled !tos!s$ w#!c# !s t#e

"o"1stop d!(!s!o" o* cells$ produc!"g a ass o*

"ew daug#ter cells$ called tuour.



:"co"trolled !tos!s



; Tuor cells t#at rea!" at or!g!"al s!te.

; Ca" 'e reo(ed surg!cally or &!lled 'y rad!at!o"$usually el!!"at!"g a"y *urt#er ca"cer de(elope"t at

t#at s!te.

<ENI3N T:4O:R



; Soe tuor cells se"d out s!g"als t#at tell t#e 'ody to

produce a "ew 'lood (essel at t#e tuor s!te.

; T#ese cells "ot o"ly #a(e t#e!r ow" *ood a"d o%yge"

supply$ t#ey also #a(e a" a(e"ue *or escape to a "ew

part o* t#e 'ody 1 t#roug# t#e "ew 'lood (essel a"d !"to'loodstrea.

4ALI3NANT T:4O:R



; Cells t#at 'rea& away *ro t#e tuor 'eg!" to spreadto surrou"d!"g t!ssues ,(!a t#e 'loodstrea or lyp#-

a"d start "ew tuors.

;T#e perso" co"cer"ed !s sa!d to 'e su**er!"g *roA)&R

; :sually surgery !s per*ored to reo(e t#e tuor$

*ollowed 'y rad!at!o" a"d c#eot#erapy.



Causes o* Ca"cer

Genetic- soe *ors o* ca"cer l!&e prostate$ colo"$ 'reast$s&!"$ o(ary are suspected to 'e !"#er!ted *ro t#e pare"ts

arcinogens- t#ese are c#e!cals w#!c# a**ect ge"et!c act!(!tya"d cause ca"cer$ e.g. o* carc!"oge" a d!esel e%#aust$

c!garette so&e$ #a!r dyes$ soot$ arse"!c$ 'e"ze"e a"d*oralde#yde.

Radiation- e%cess e%posure to %1ray$ gaa1rays a"d ultra(!olet rays lead to !"crease ca"cer r!s&.

*iruses- soe (!ruses ,suc# as t#e HPV a"d HIV1/- causeca"cer.



LE:=AE4IA

; !s caused 'y utat!o" ,c#a"ge !" ge"et!c !"*orat!o"-

; T#e utat!o" causes t#e 'o"e arrow to produce red 'lood cells a"d platelets at a rate t#at !s uc# slower

t#a" "oral

; He"ce$ a leu&ae!a pat!e"t su**ers *ro !"su**!c!e"to%yge"$ wea&"ess a"d d!!*!culty !" 'lood clott!"g



INTESTINES CANCER



Appl!cat!o" o* 4!tos!s !" Clo"!"g

4!tos!s !s used to impro(e the +ualit!$ to

produce new species a"d to ensure

uniformit! in the traits. loning+ process o* art!*!c!ally creat!"g a "ew

!"d!(!dual t#at !s ge"et!cally !de"t!cal to a"

e%!st!"g !"d!(!dual.

Tec#"!7ue !" appl!cat!o" o* !tos!s !" clo"!"g

tissue culture.



Appl!cat!o" o" !tos!s !" clo"!"g

,lant tissue

S"in tissue

100215555 Cell Division Ppt

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