B2 Cell Division

Doesn't include cancer

__ are inside the __

and so on…

Chromosomes inside nucleus

Chromosomes made of DNA strands, called genes

Why do cells divide?

to replace damaged cells and grow the organism.

In letters what is the difference between men and women DNA?

men: xy

women: xx

what are the 3 stages of the cell division process?

1. interphase

2. mitosis

3. cytokinesis

Describe the interphase

• cells get bigger

• sub cellular organelles increase in numbers

• chromosomes duplicate into 2 copies ( 46→92)

Describe the mitosis phase

• nucleus divides into 2 , pulled apart by spindle fibres

• each copy of the genetic material moves to different ends of the cell, pulled by spindle fibres

describe the cytokinesis phase

• cell divides into 2

• cytoplasm and cell membrane divide in middle of cell

• 2 identical daughter cells produced with exact same chromosomes as parent cell

which is the longest part?

interphase, by far. Followed by mitosis. cytokinesis is shortest time.

what are the 2 types of human stem cell?

• embryonic

• adult (though kids too), so we call it tissue

What is the difference between the 2 types of human stem cell?

embryonic → any cell

adult → only some cells

adult stem cells can’t turn into certain types of cell. this makes embryonic more useful.

How does therapeutic stem cell use work?

it is when you remove the nucleus from the embryonic stem cell and put the patient’s adult nucleus in so the body doesn’t reject it.

Where are stem cells found in plants?

meristems → can turn into any plant cell

give 1 advantage and disadvantage of the use of plant clones

Advantage: rare species can be prevented from extinction.

Disadvantage: no variation so an entire crop could be quickly wiped out by a disease.

Advantages and disadvantages of adult stem cell use

fewer ethical issues

consent can be given

hard to find suitable donor

high rejection chance

only differentiate into some cell types

advantages and disadvantages of embryonic stem cell use

can differentiate into any cell

ethical issues

destroying embryo risk