7/17/2019 Meiosis Cantidad Cromosomas y Adn

http://slidepdf.com/reader/full/meiosis-cantidad-cromosomas-y-adn 1/4

PLOIDY, WHAT IS IT? MITOSIS vs MEIOSIS

HOW MEIOSIS AND MITOSIS DIFFER

MITOSIS

 

1. Occurs in somaic c!""s an# $! s!m c!""s o% $! &!rm c!"" "in!.

'. On! c!"" #ivision r!su"s in ' n!( c!""s.

). Eac$ o% $! ' n!( c!""s r!c!iv!s on! com*"!! s! o% !ac$ ori&ina" *air o% c$romosom!s in$! #ivi#in& c!"".

+. Eac$ o% $! ' n!( c!""s conains a #i*"oi# num!r -'c o% c$romosom!s an# #i*"oi# -'n&!n!ic con!n.

 

MEIOSIS

 

1. Occurs on"/ in &am!oc/! sa&!s o% $! &!rm c!""s.

'. T(o c!"" #ivisions r!su" in + n!( c!""s.

). Eac$ o% $! + n!( c!""s r!c!iv!s on"/ on! c$romosom! o% !ac$ ori&ina" *air o%c$romosom!s *r!s!n in $! *rimar/ &am!oc/!.

+. Eac$ o% $! + n!( c!""s conains a $a*"oi# num!r -1c o% c$romosom!s an# $a*"oi# -1n&!n!ic con!n.

 PLOIDY, WHAT IS IT?

 A"" o% us $av! $!ar# or s!!n $! !rms $a*"oi# an# #i*"oi# #urin& our !#ucaion an# r!a#in& in$! io"o&ica" sci!nc!s, u ($a #o $!s! !rms m!an an# $o( #o $!/ r!"a! o c!""sun#!r&oin& m!iosis? T$! !0*"anaions ar! o%!n vari!# an# som!im!s mis"!a#in&. T$is is%ur$!r com*"ica!# / $! %ac $a !ac$!rs an# au$ors ma/ r!%!r o *"oi#/ in !rms o% !i$!r&!n!ic con!n -n or c$romosom! num!r -c an#, un%oruna!"/, $!/ som!im!s &! $!s!(o #i%%!r!n an# im*oran conc!*s con%us!#.

 An/ #i*"oi# or&anism is %orm!# %rom $! %usion o% $a*"oi# &am!!s i.!. an !&& %rom $!2mo$!r2 an# a s*!rm %rom $! 2%a$!r.2 I% (! ar! a"3in& aou mu"ic!""u"ar anima"s 4man/*"ans ar! *o"/*"oi#5 suc$ as /ou an# I, asi#! %rom our &am!!s $a $av! com*"!!# m!iosisan# o$!r c!""s $a $av! r!*"ica!# $!ir DNA in *r!*araion %or c!"" #ivision, n!ar"/ a"" c!""s o%$a or&anism ar! #i*"oi# in !rms o% o$ &!n!ic con!n an# c$romosom! num!r -an!0am*"! o% an !0c!*ion o $is sa!m!n is $! maur! mamma"ian !r/$roc/! ($ic$ $as"os is nuc"!us an# $us $as no c$romosom!s an# no *"oi#/.

7/17/2019 Meiosis Cantidad Cromosomas y Adn

http://slidepdf.com/reader/full/meiosis-cantidad-cromosomas-y-adn 2/4

So, $o( #o (! #!%in! *"oi#/ in !rms o% &!n!ic con!n -n in a #i*"oi# $uman c!""? A $umanc!"" $a is #i*"oi# in !rms o% &!n!ic con!n conains +6 c$romosom!s $a ma3!u* ''$omo"o&ous *airs *"us an 7 an# a Y c$romosom! -s!0 c$romosom!s ma3in&8u* a ')r# *air.

W$!n (! sa/ $!s! c!""s ar! #i*"oi# -'n in !rms o% &!n!ic con!n (! ar! r!%!rrin& o $!%ac $a !ac$ $omo"o&ous *air -inc"u#in& $! 7 an# Y *air o% c$romosom!s consiss on on!ma!rna""/ #!riv!# c$romosom! -a co*/ o% on! $a (as in $! mo$!r9s !&& an# on!*a!rna""/ #!riv!# c$romosom! -a co*/ o% on! $a (as in $! %a$!r9s s*!rm. T$!r! is no$ir# *ar/ invo"v!#: W! ar! "oo3in& a $! %ac $a !ac$ *air $as on"/ ma!rna" an# *a!rna"com*on!ns. I% (! r!*"ica! $!s! c$romosom!s in *r!*araion %or #ivision (! no( $av! (oma!rna" c$romai#s an# (o *a!rna" c$omai#s. Eac$ o% $!s! c$romai#s r!*r!s!ns acom*"!! c$romosom!, u, uni" $! c!"" #ivi#!s, $! (o ma!rna""/ #!riv!# c$romai#sr!main conn!c!# a $! c!nrom!r! as #o $os! $a ar! *a!rna""/ #!riv!#. T$us, arrin& as*onan!ous"/ a**!arin& muaion, (! $av! a##!# no$in& n!( in !rms o% &!n!ic con!n.

W! si"" $av! on"/ ma!rna" an# *a!rna" com*on!ns an# $! c!"" is si"" consi#!r!# o ! 'n.

T$! 2'2 si&ni%i!s $! %ac $a !ac$ *air o% c$romosom!s is r!*r!s!n!# / on"/ a ma!rna"an# a *a!rna" com*on!n -no %ra!rna"s $!r!, $us, $! ma0imum num!r o% #i%%!r!n &!n!a""!"!s $a can !0is a a &iv!n &!n! "ocus on a $omo"o&ous *air o% c$romosom!s is ' -asim*"! !0am*"! o% $is (ou"# ! on! #ominan an# on! r!c!ssiv! a""!"!. T$! 2n2 can !vi!(!# as $! num!r o% $omo"o&ous *airs o% c$romosom!s $o(!v!r, a mor! *r!cis!#!%iniion (ou"# ! $a 2n2 is $! num!r o% $omo"o&ous *airs o% &!n! "oci on a""c$romosom!s *r!s!n in $! c!"".

P"oi#/ in !rms o% c$romosom! num!r -c is a"o&!$!r #i%%!r!n. In $is cas! (! ar! sim*"/conc!rn!# (i$ $! oa" num!r o% c$romosom!s -amoun o% DNA an# no a a"" conc!rn!#aou &!n! "oci or ($!$!r $! c$romosom!s ar! ma!rna" or *a!rna". A $uman c!"" $a is#i*"oi# in !rms o% c$romosom! num!r -'c a"so conains +6 c$romosom!s $a ma3!u* ')*airs. T$! 2'2 si&ni%i!s $! %ac $a !ac$ *air o% c$romosom!s is r!*r!s!n!# / (oc$romosom!s. T$! 2c2 is $! oa" num!r o% *airs o% c$romosom!s in $! c!"". W$!n $is c!""r!*"ica!s is DNA in *r!*araion %or #ivision i ma3!s co*i!s o% !v!r/ c$romosom!. Eac$ o%$! r!*"ica!# c$romosom!s consiss o% (o c$omai#s $a ar! conn!c!# a $! c!nrom!r!an#, as aov!, !ac$ o% $!s! c$romai#s r!*r!s!ns a com*"!! c$romosom!. T$us, (! $av!no( #ou"!# $! num!r o% c$romosom!s in $! c!"" an# *"oi#/ in !rms o% c$romosom!num!r is +c. T$! 2+2 si&ni%i!s $! %ac $a !ac$ *air o% c$romosom!s is no( r!*r!s!n!# /+ c$romosom!s -i.!., ' co*i!s o% !ac$ m!m!r o% $! ori&ina" *air or c$romosom!s. T$! 2c2is $! oa" num!r o% *airs o% c$romosom!s in $! c!"".

I% (! no( a**"/ $!s! %acs o $! *roc!ss o% m!iosis, (! can s!! $o( *"oi#/ in !rms o%&!n!ic con!n an# c$romosom! num!r #i%%!rs as m!iosis occurs. Iniia""/ -!%or!r!*"icaion o% $! DNA o% $! c$romosom!s, $! *rimar/ &am!oc/! is 'n -#i*"oi# in !rms o%&!n!ic con!n an# 'c -#i*"oi# in !rms o% $! num!r o% c$romosom!s, as #!scri!# %or a#i*"oi# c!"" aov!. T$! *rimar/ &am!oc/! $!n r!*"ica!s is c$romosom!s -is DNA. A%!r$is r!*"icaion is com*"!!, $! c!"" is si"" 'n -no n!( &!n! a""!"!s $av! !!n a##!#, u

7/17/2019 Meiosis Cantidad Cromosomas y Adn

http://slidepdf.com/reader/full/meiosis-cantidad-cromosomas-y-adn 3/4

sinc! $! oa" num!r o% c$romosom!s $as #ou"!# -as #!scri!# aov! i is no( +c -a!ra*"oi# num!r o% c$romosom!s.

N!0 $! %irs m!ioic #ivision a3!s *"ac!. A $is im! $! r!*"ica!# ma!rna" an# *a!rna"c$romosom!s o% !ac$ *air ar! s!*ara!# %rom !ac$ o$!r an# s!&r!&a!# ino on! or $!o$!r o% $! (o s!con#ar/ &am!oc/!s $a ar! %orm!#. As a r!su", !ac$ s!con#ar/&am!oc/! conains on"/ on! r!*"ica!# c$romosom! -an ori&ina" an# a co*/ o% !ac$ori&ina" *air o% c$romosom!s. T$us, (! $av! r!#uc!# $! *"oi#/ in !rms o% &!n!ic con!n o1n -$a*"oi# &!n!ica""/, sinc! %or !ac$ &!n! "ocus, on"/ on! o% $! (o *ossi"! a""!"!s is*r!s!n. Sinc! $! oa" num!r o% c$romosom!s -in $! %orm o% c$romai#s in !ac$s!con#ar/ &am!oc/! is no( 1;' o% ($a i (as !%or! $! #ivision, $! *"oi#/ in !rms o%c$romosom! num!r is no( 'c. T$os! o% /ou ($o ar! r!a""/ $in3in& $ar# aou $is ma/$av! r!a"i<!# $a cross8ov!r cou"# con%oun# $is *icur! %or som! &!n! "oci $o(!v!r, ($a(! ar! #iscussin& $!r! is an 2i#!a"2 !0am*"! an# ($a $a**!ns in $! cas! o% $! ma=ori/ o%&!n! "oci o% an/ $omo"o&ous *air.

N!0, !ac$ s!con#ar/ &am!oc/! #ivi#!s. A $is im!, $! (o c$romai#s o% !ac$ r!*"ica!#c$romosom! in $! s!con#ar/ &am!oc/! s!*ara! a $! c!nrom!r! an# $! r!su"in&i#!nica" c$romosom!s -ori&ina" an# co*/ %rom !ac$ r!*"ican ar! s!&r!&a!# ino !ac$ o%$! (o c!""s $a ar! %orm!#. T$us, !ac$ n!( c!"" $as !i$!r a *a!rna" or a ma!rna"c$romosom! -u no o$ %rom !ac$ ori&ina" $omo"o&ous *air an# a *"oi#/ in !rms o%&!n!ic con!n o% 1n -si"" on"/ on! o% (o *ossi"! a""!"!s %or !ac$ &!n! "ocus. Sinc! $!oa" num!r o% c$romosom!s $as !!n r!#uc!# o 1;' $! num!r *r!s!n in $! s!con#ar/&am!oc/!, $! *"oi#/ in !rms o% c$romosom! num!r is no( 1c -$a*"oi# num!r o%c$romosom!s. So, $! r!su"in& &am!! -or &am!!s in $! cas! o% $! ma"! (i"" ! $a*"oi#in !rms o% o$ &!n!ic con!n -1n an# c$romosom! num!r -1c.

T$! %i&ur! !"o( summari<!s $! *roc!ss o% m!iosis an# $! c$an&!s in *"oi#/ $a occura"on& $! (a/. In $is #ia&ram, $! #as$!# circ"! surroun#in& $! c$romosom!s r!*r!s!ns$! oun#ar/ o% $! nuc"!ar m!mran! -($ic$ is acua""/ no *r!s!n #urin& #ivision. On"/(o *airs o% c$romosom!s ar! s$o(n in $is !0am*"! $o(!v!r, $! *"oi#i!s &iv!n %or !ac$sa&! -!.&. 'n, 'c in $! m!ioic c/c"! (ou"# ! $! sam! r!&ar#"!ss o% $o( man/c$romosom! *airs ar! *r!s!n in $! ori&ina" *rimar/ &am!oc/! sinc! $!s! num!r;"!!rcominaions r!*r!s!n a %ormu"a, no an acua" num!r. R!m!m!r, *"oi#/ in !rms o%&!n!ic con!n is r!*r!s!n!# / 2n.2 P"oi#/ in !rms o% c$romosom! num!r -amoun o%DNA is r!*r!s!n!# / 2c.2

7/17/2019 Meiosis Cantidad Cromosomas y Adn

http://slidepdf.com/reader/full/meiosis-cantidad-cromosomas-y-adn 4/4