cell division and stem cells

Question 1

what is a chromosome

Answer 1

chromosomes are linear arrangements of genes found in pairs in the nucleus of body cells

Question 2

what are the male and female sex chromosomes

Answer 2

male = XY
female = XX

Question 3

what is the purpose of mitosis and how does it work

Answer 3

mitosis is used for growth and repair
The DNA within the mother cell duplicates, so the cell now has 2 pairs of chromosomes. The chromosomes line up in the middle and the cell pulls apart, creating two genetically identical daughter cells.

Question 4

how is cancer caused

Answer 4

cancer occurs when the genes that control cell division stop functioning, and cells divide out of control

Question 5

what is the purpose of meiosis and how does it work

Answer 5

meiosis is used for sexual reproduction
The DNA within the mother cell (which in this case is a gamete) duplicates, so the cell now has 2 pairs of chromosomes. The cell then splits, then splits again, creating 4 genetically different gametes with half the number of chromosomes as the mother cell.

Question 6

what are stem cells and what are they used for

Answer 6

Stem cells are unspecialised cells that have the ability to differentiate into other cells. Once they have specialised, they are unable to differentiate into a different type of cell. Medically, they are used to treat many diseases and to replace damaged tissue.

Question 7

where are adult stem cells obtained from, and what are their advantages and disadvantages in their usage

Answer 7

adult stem cells are obtained from bone marrow, umbilical cords and babies’ teeth

advantages:
- the body will accept the cells so there will be no risk of rejection
- no moral or ethical issues are involved

disadvantages:
- complicated and the technology is still being developed
- they cant develop into as many types of cells as embryonic stem cells

Question 8

where are embryonic stem cells obtained from, and what are their advantages and disadvantages in their usage

Answer 8

embryonic stem cells are obtained from embryos

advantages:
- source of cells readily available from IVF treatment
- can differentiate into more types of cells than adult stem cells

disadvantages:
- some people believe that destroying embryos means the destruction of potential human life, therefore there are ethical issues involved

Question 9

what are meristems

Answer 9

meristems are a source of stem cells in plants, and are found in growing points, such as the tips of shoots and roots