GCSE Biology Week 4 Cell Division

7/21/2019 GCSE Biology Week 4 Cell Division

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e.g. a muscle or sperm cell will have many mitochondria,while a bone cell has very few.

It is not just the shape of different cells that varies, butalso the numbers of each of there organelles…



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Similar cells !

grouped into totissues ! organs& ! organs intosystems forincreasedefficiency.



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DIPLOID

Through a processcalled… Mitosis!



M i t o s i s i s t h e p r o c e s s o f n o r m a l c ed i v i s i o n .

In mitosis, thechromosomes are copied

and divided equally between the 2 new

daughter cells. ..



...So each mitotic division produces2 cells...



Som e cells in the hum an body are not diploid Gam etes contain only 1copy of each gene as they have only 1 set of chrom osomes

These cells are .............. and are produce

special type of cell division called .......Haploid

Meio



A male andFemale gamete jointogether at fertilisation..

Tthe

forming a. zy

Mta



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Remember...This is key to understanding why

organisms vary!



The Appearance, numberand arrangement ofchromosomes in thenucleus are referred to as

the karyotype.



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Mitosis results in 2identical cells… and someorganisms use mitosis to

reproduce!

E.g. Aphids andStrawberries…

Thisreprodcalledrepro

All have esame

the

…and StrawberMitosis is great forgrowth and repair " …

but since all “daughters”are clones – there is NO

genetic variation #

GCSE Biology Week 4 Cell Division

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