cell division

Question 1

what is differentiation?

Answer 1

the process of a cell changing to become specialised for its job.

Question 2

what are undifferentiated cells called?

Answer 2

stem cells.

Question 3

what are 5 examples of specialised cells and what do the do? (the ones you have to know)

Answer 3

sperm cell - reproduction
nerve cell - rapid signalling
muscle cell - contraction
root hair cell - absorbing water and minerals
phloem and xylem - transporting substances

Question 4

what are chromosomes?

Answer 4

coiled lengths of DNA that carry lots of genes for various characteristics.

Question 5

what are the stages of the cell cycle? (mitosis)

Answer 5

the cell cycle is body cells dividing to produce new cells.
1. the cell grows and creates more subcellular structures.
2. the cell duplicates its DNA and forms x shaped chromosomes.
once everything is copied the cell is ready for mitosis.
1. chromosomes lines up at the centre of the cell and cell fibres pull them apart.
2. the 2 arms of the chromosomes go to sperate sides of the cell.
3. membranes form around the chromosomes to become the new nucleuses.
4. the cytoplasm and cell membrane split to make 2 daughter cells. (the cells are identical)

Question 6

how do cells replicate by binary fission?

Answer 6

binary fission is used by prokaryotic cells.
1. the circular DNA and plasmids replicate.
2. the cell gets bigger and only the circular DNA moves to opposite sides.
3. the cytoplasm begins to divide and new cell walls begin to form.
4. the cytoplasm divides and and 2 daughter cells are produced, each has 1 copy of circular DNA by a variable number of plasmids.