B2 - cell division

what are chromosomes n where are they found?

• chromosomes are made of DNA

• they are found in the nucleus - in pairs (one chromosome from each parent)

• each chromosome carries genes

cell cycle definition

cell cycle is when body cells divide in a series of stages.

stage 1 of cell cycle

• DNA replicates to form two copies of each chromosome

• cells grow in size

• makes copies of internal structures, ribosomes n mitochondria

stage 2 of cell cycle

• mitosis occurs

• 1 set of chromosomes is pulled to each side of cell

• nucleus divides

stage 3 of cel cycle

• cytoplasm divides

• cell membrane divides

• form two identical cells (daughter cells)

what are the functions of mitosis?

• needed for growth n repair of organisms

• mitosis occurs when organisms repairs itself

• mitosis is asexual reproduction

stem cells definition

a stem cell is an undifferentiated cell. this means that it has not yet specialised, n has the ability to differentiate n form a specialised cell.

where are stem cells found?