1.1

Question 1

what is a somatic cell

Answer 1

any cell in the body other than the cells involved in reproduction

Question 2

are somatic celle diploid or haploid

Answer 2

diploid

Question 3

how do somatic cells divide

Answer 3

mitosis

Question 4

are the same number of chromosomes passed onto the daughter cell
(mitosis)

Answer 4

yes

Question 5

steps of mitosis

Answer 5

1. chromosomes duplicate
2. chromosomes line up along the equator
3. chromatids are pulled apart to separate poles by spindlefibres
4. cell divides into 2 daughter cells with 4 chromosomes

Question 6

what is meiosis

Answer 6

a type of cell devision that results in half the number of chromosomes as the parent cell

Question 7

where does meiosis take place

Answer 7

the testis and the ovaries

Question 8

what are germline cells

Answer 8

they are gametes and the stem cells that divide to form gametes

Question 9

how do germline cells divide

Answer 9

the nucleus of germaines cells divide my mitosis to form 2 identical daughter cells

these daughter germline cells then divide by meiosis to from four haploid gametes

Question 10

what does germline division by mitosis produce

Answer 10

germline stem cells

Question 11

what does division by meiosis produce

Answer 11

haploid gametes

Question 12

what is cellular differentiation

Answer 12

the process by which a cell expresses certain genes to produce proteins characteristic for that cell type

Question 13

why does differentiation allow the cell to carry out

Answer 13

specialised functions

Question 14

what are stem cells

Answer 14

unspecialised cells that can self renew or differentiate into specialised cells

Question 15

what are the two types of stem cells

Answer 15

embryonic and tissue

Question 16

where are embryonic and tissue stem cells found

Answer 16

• very early embryo
• particular tissues and organs throughout the body

Question 17

are embryonic stem cells multi or pluripotent

what does that mean

Answer 17

pluripotent
means they have all their genes switched on so they can differentiate into all the cell types

Question 18

are tissue stem cells multi or pluripotent

what does this mean

Answer 18

multi-potent
only have some genes switched on and so can only differentiate into particular tissues

Question 19

what are stem cells used as model cells for

Answer 19

-providing info on cell processes such as cell growth, differentiation and gene regulation work

• study how diseases and disorders develop
• test the response of cells to new drugs

Question 20

what are examples of therapeutic uses of stem cells and explain the processes

Answer 20

• stem cell skin grafts
  • culture skin stem cells and spray onto damaged skin to repair it
• corneal repair
  • culture corneal stem cells and place over damaged cornea to regenerate it

Question 21

what are the ethical issues of stem cells

Answer 21

it destroys the embryo and people view it as destroying a human life

Question 22

what causes a tumour to grow

Answer 22

cancer cells stop responding to regulatory signals that control cell division and divide excessively to form a mass of abnormal cells

Question 23

what are benign tumours

Answer 23

tumours that remain in one place and don’t spread throughout the body
e.g warts and moles

Question 24

what causes malignant tumours

Answer 24

when cells within a benign tumour fail to attach to each other and spread throughout the body through the bloodstream forming secondary tumours