1.2.3 Stem Cells

Question 1

Gamete

Answer 1

Sex cells

Question 2

Zygote

Answer 2

• When the gametes fuse
• the fertilised cell

Question 3

Embryo

Answer 3

When the cells are dividing

Question 4

Foetus

Answer 4

When you can see the features of the animal

Question 5

Differentiated

Answer 5

The process by which a cell becomes specialised

Question 6

Stem cells

Answer 6

Undifferentiated cells that can become specialised

Question 7

What can stem cells do? (2p)

Answer 7

Divide to produce new cells
Regenerate and repair tissues

Question 8

What makes specialised cells different from each other?

Answer 8

They have different functions

Question 9

When do cells become specialised in animals?

Answer 9

Early in life (mostly before birth)

Question 10

When specialised cells divide, what can they form?

Answer 10

Only make more of the same cell

Question 11

What types of cells can’t divide? (2p)

Answer 11

Red blood cells
Skin cells

Question 12

How do cells that can’t divide get replaced?

Answer 12

Adult stem cells replace the dead or damaged cells

Question 13

What is different about nerve cells?

Answer 13

They can’t divide once differentiated or be replaced by stem cells

Question 14

When do plants cells differentiate?

Answer 14

All through their lives

Question 15

What are meristems?

Answer 15

-Active regions of the thr stem and foots of plants
- Mitosis occurs here

Question 16

Is differentiation permanent in plants?

Answer 16

No, you can move a plant cell from one part to the other, and it will redifferentiate

Question 17

What does cloning produce?

Answer 17

Genetically identical offspring

Question 18

Why is cloning more difficult in aminals than plants?

Answer 18

Animals differentiate permanently from birth

Question 19

Difference between stem cells and body cells

Answer 19

Stem cells are undifferentiated
Body cells are differentiated

Question 20

Sources of stem cells (3p)

Answer 20

Adult stem cells
From umbilical chord
Embryonic

Question 21

Why is the cloning of plants and advantage to plant research?

Answer 21

Researchers can change different variables to learn about a species

Question 22

Uses of stem cells

Answer 22

Replace damaged cells
Regenerative tissues
Drug development
Regenerative medicine

Question 23

Points in favour of embryonic stem cells (4p)

Answer 23

• they could be used to grow new tissues and organs for transplants
• help to find treatments for things like diabetes and Alzheimer’s
• Are generally spare from IVF so they would be destroyed anyway
• If from umbilical chord, no embryos need to be destroyed

Question 24

Points against embryonic stem cells (4p)

Answer 24

• It is wrong to destroy potential babies
• Embryos can’t give consent so it’s unethical
• Very expensive and could cause future problems such as development of cancers
• Takes a lot of time and money would be better spent on other possible treatments

Question 25

What is an embryonic stem cell?

Answer 25

A stem cell that comes from a fertilised and dividing cell