B2 quick questions

Question 1

what is a stem cell

Answer 1

an undifferentiated cell that can differentiate to become specialised to any function

Question 2

what are adult stem cells

Answer 2

stem cells from adults that an only differentiate into certain specialised cells

Question 3

where are adult stem cells found

Answer 3

bone marrow

Question 4

what are embryonic stem cells

Answer 4

stem cells from embryos that can differentiate into any type of specialised cell

Question 5

where are embryonic stem cells found?

Answer 5

in the embryos usually from spare embryos in fertility clinics

Question 6

what is therapeutic cloning

Answer 6

patients cells are used to create an early embryo clone of themselves- stem cells from the embryo can then be used to treat the patients condition this reduces chances of rejection

Question 7

give one advantage of using therapeutic cloning

Answer 7

stem cells from the embryo are not rejected because they have the same genes as the patient

Question 8

give one advantage of using adult stem cells

Answer 8

fewer ethical issues as obtained from adults who can consent to their use

Question 9

give two disadvantages of using adult stem cells

Answer 9

• can take a long time for a suitable donor to be found

- can only differentiae into some specialised cells so can treat less diseases

Question 10

give two advantages of using embryonic stem cells

Answer 10

• can differentiate into any specialised cell so can be used to treat many diseases
• easier to obtain as they are found in he spare embryos at fertility clinics

Question 11

give two disadvantages of embryonic stem cells

Answer 11

• ethical issues surrounding their use as every embryo is a potential life
• potential risk involved with treatments, such as transfer of viral infections

Question 12

what are plant meristems

Answer 12

area where rapid cell division occurs in roots and shoots of plants

Question 13

give two advantages of using meristem to clone plants

Answer 13

• rare species can be cloned to protect them from extinction

- plants with special features eg disease resistance can be cloned to produce many copies

Question 14

give a disadvantage of using meristem to clone plants

Answer 14

no genetic variation so for example an entire cloned crop could be killed by disease

Question 15

what is cell division by mitosis

Answer 15

body cells divide to form two identical daughter cells

Question 16

what is the purpose of mitosis

Answer 16

growth and repair of cells as well as asexual reproduction

Question 17

what happens during the first stage of the cell cycle

Answer 17

cell grows, increase of subcellular structures like mitochondria and ribosomes, chromosomes duplicate

Question 18

what happens during mitosis

Answer 18

one set of each chromosome is pulled to either end of the cell and the nucleus divides

Question 19

what happens in cytokinesis

Answer 19

the cytoplasm and cell membrane divide forming two identical daughter cells

Question 20

1m=1cm=1mm=1micrometer=1nm

how much do you have to times or divide by to get to each

Answer 20

1m x 100 = 1cm
1cm x 10 = 1mm
1mm x 1000 = 1 micrometre
1 micrometre x 1000 = 1nm