B2

Question 1

What are new cells needed for?

3 things

Answer 1

Growth
Replace worn out cells
Repair damaged cells

Question 2

What are genes?

Answer 2

Small sections of dna that code for a protein

Question 3

What are chromosomes?

Answer 3

Large sections of dna that contain many genes

Question 4

How many chromosomes in sex cells?

Answer 4

23

Question 5

Why do red blood cells have no chromosomes?

Answer 5

They have no nucleus

Question 6

2 places in an adult where there is rapid cell division?

Answer 6

Hair follicles

Skin

Question 7

What happens in stage 1 of cell cycle

Answer 7

All dna and organelles are replicated ready for cell division

Question 8

What happens in stage 2 of cell cycle?

Answer 8

Nucleus divides by mitosis

Question 9

What happens in stage 3 of cell cycle?

Answer 9

Cytoplasm and cell membranes divide to form 2 identical daughter cells

Question 10

What happens to cells as they divide and develop?

Answer 10

They differentiate

Question 11

What are stem cells?

Answer 11

Unspecialised cells

Question 12

Where are unspecialised cells in plants?

Answer 12

Growing regions of the stem and roots called meristems

Question 13

Explain what happens in the meristems

Answer 13

1) mitosis continuously takes place
2) cells elongate and grow
3) they get to their final position in the plant and then differentiate

Question 14

Can plant cells re differentiate?

Answer 14

Yes. If they are moved to another part of the plant

Question 15

What is cloning?

Answer 15

Producing genetically identical offspring

Question 16

How do you clone a plant?

3

Answer 16

1) get a leaf and chop it up
2) place the pieces into a growth medium which causes the cells to undifferentiate and divide
3) change the growth conditions to cause cells to differentiate

Question 17

Why can animals not be cloned?

Answer 17

Their cells cells differentiate permanently.

can not undifferentiate

Question 18

2 types of stem cells

Answer 18

Embryonic stem cells

Adult stem cells

Question 19

What are embryonic stem cells?

Answer 19

Found in embryos and can differentiate into all types of cells in body

Question 20

What are adult stems cells?

Answer 20

Cells that can differentiate into a few types of cells

Question 21

3 conditions that can be treated with stem cells

Answer 21

Nerve damage
Diabetes
Organ failure

Question 22

How can stem cells fix diabetes?

Answer 22

1) pancreatic cells that produce insulin developed from embryonic stem cells
2) they are implanted into diabetic patient

Question 23

3 uses of cloned plants from stem cells

Answer 23

1) can produce large number of rare plants
2) can produce large population of identical plants for research
3) used in horticulture

Question 24

2 sources of embryonic stem cells

Answer 24

Aborted embryos

Spare embryos

Question 25

What are the ethical problems with using embryonic stem cells?

Answer 25

No permission so violation of human rights

Religious beliefs

Question 26

2 procedural problems with embryonic stem cells

Answer 26

1) slow expensive and hard to control

2) the cells divide rapidly so risk of causing cancer

Question 27

Problems with using adult stem cells

Answer 27

Could be infected with viruses which could then be transferred
Require immunosuppressant drugs

Question 28

Describe the process of therapeutic cloning

Answer 28

1) cells removed from patient
2) cells are used to make a cloned early embryo of patient
3) stem cells removed from this embryo and used to grow organs an tissues
4) these tissues/organs transplanted into patient. No risk of rejection as they are seen as self