Key Area 1

Question 1

Which 2 types of human cells are there?

Answer 1

Somatic and Germline

Question 2

what are somatic cells?

Answer 2

any cell in the body other than those involved in reproduction

Question 3

give 3 examples of a somatic cell

Answer 3

bone, lung, brain, blood, heart muscle, skeletal muscle, pancreatic, kidney, liver

Question 4

how to somatic cells divide?

Answer 4

mitosis

Question 5

what does mitosis allow to be maintained?

Answer 5

diploid chromosome compliment

Question 6

how many pairs of homologous chromosomes do diploid cells have?

Answer 6

23

Question 7

where are germline cells found?

Answer 7

reproductive organs

Question 8

what are germline cells

Answer 8

stem cells that divide to form gametes

Question 9

give 2 examples of a gamete

Answer 9

sperm ova

Question 10

how do germline cells divide?

Answer 10

mitosis and meiosis

Question 11

what happens when germline cells divide by mitosis?

Answer 11

more germline stem cells are produced

Question 12

what happens when germline cells divide by meiosis?

Answer 12

haploid gametes are produced

Question 13

which 2 divisions must a cell undergo in meiosis

Answer 13

separating homologous chromosomes

separating chromatids

Question 14

how many single chromosomes do haploid gametes have?

Answer 14

23

Question 15

why do cells need different genes to be expressed?

Answer 15

genes carry the code to make proteins and different proteins are needed for different cells

Question 16

what are housekeeping genes?

Answer 16

genes required by every cell to maintain basic functions and structures

Question 17

give 2 examples of genes only needed by specific cells

Answer 17

pancreatic cells need genes to produce insulin and glucagon

stomach cells need genes to produce pepsin for digestion

Question 18

describe gene expression

Answer 18

all cells contain all genes ( in somatic cells ) but only some are required for each cell. the cell can turn on (express) genes that are required and turn off any that are not

Question 19

what is cellular differentiation?

Answer 19

the process by which a cell expresses certain genes to produce proteins needed for that type of cell.

Question 20

What does cellular differentiation allow?

Answer 20

allows cells to go from an unspecialised stem cell to a cell which can carry out a specialised function

Question 21

do all stem cells differentiate?

Answer 21

no, some will self renew

Question 22

describe cellular differentiation in an early embryo

Answer 22

cells can differentiate into all cell types because all genes can be expressed

Question 23

what term is used to describe embryonic stem cells?

Answer 23

pluripotent

Question 24

what are tissue stem cells involved in?

Answer 24

growth, repair and renewal of cells found in that tissue

Question 25

what can tissue stem cells differentiate into?

Answer 25

all types of cell found in a particular type of tissue

Question 26

why can tissue stem cells only differentiate into cells found in a particular type of tissue

Answer 26

only some genes in tissue stem cells can be expressed

Question 27

what can blood stem cells located in bone marrow differentiate into?

Answer 27

red blood cells platelets phagocytes lymphocytes

Question 28

what term is used to describe tissue stem cells?

Answer 28

multi potent

Question 29

why are embryonic stem cells used in research?

Answer 29

the embryo can self renew under the right conditions

Question 30

give 2 examples of therapeutic uses of stem cells

Answer 30

corneal repair | regeneration of damaged skin

Question 31

give 2 examples of research uses of stem cells

Answer 31

provides information on cell growth, differentiation and gene regulation work study how diseases develop or can be used in drug testing

Question 32

what are the ethical issues surrounding embryonic stem cell use?

Answer 32

- offers effective treatment of disease and injury | - involves destruction of embryos and potential life

Question 33

what signals do cells constantly send?

Answer 33

regulatory signals both internally and externally

Question 34

when are cell signals sent and detected?

Answer 34

if the cell's DNA becomes damaged

Question 35

what happens after the cell sends signals and the signals are detected?

Answer 35

action is taken to repair DNA damage

Question 36

What happens to a cell if DNA damage cannot be repaired?

Answer 36

the cell will send another signal instructing apoptosis

Question 37

what is apoptosis?

Answer 37

programmed cell death

Question 38

what does apoptosis prevent?

Answer 38

the damaged cell undergoing mitosis

Question 39

when does cancer occur?

Answer 39

when apoptosis fails and the cell does not die, instead, the damaged cell divides excessively

Question 40

what does the failure of apoptosis result in

Answer 40

a mass of abnormal cells ( tumour ) forming

Question 41

what happens if tumours fail to attach to each other?

Answer 41

they can spread around the body and cause secondary tumours to form