B2 - Cell Division

Question 1

Why are new cells often needed

Answer 1

to grow and replace dead cells, to repair damaged tissue

Question 2

Where are the genes in an animal (full flow chart)

Answer 2

genes -> DNA -> chromosomes -> nucleus

Question 3

What do genes contain

Answer 3

all the instructions for making new cells, tissues and organs

Question 4

What is a gene

Answer 4

a small packet of information that controls a characteristic

Question 5

How many genes are in a chromosome

Answer 5

hundreds or thousands

Question 6

How many chromosomes do body cells have

Answer 6

46

Question 7

How many chromosomes do gametes have

Answer 7

23

Question 8

What is the process through which asexual reproduction happens

Answer 8

mitosis

Question 9

WHat are the three stages of the cell cycle
- What happens in each stage

Answer 9

growth - sub-cellular structures double in number
mitosis - nucleus divides
cytokinesis - cell divides in two

Question 10

How many cells are produced from mitosis
- what are they called

Answer 10

2 daughter cells

Question 11

how many cells approximately die each minute

Answer 11

around 300 million

Question 12

What are stem cells

Answer 12

unspecialised cells that can become any type of cell

Question 13

how to cells differentiate

Answer 13

some genes are switched on and off to do particular functions

Question 14

what types of cell cannot divide
- what happens to them

Answer 14

• RBCs and WBCs get replaced by adult stem cells
• nerve cells usually do not grow back

Question 15

What is the difference between animal and plant cells in regards to differentiating

Answer 15

animal cells only differentiate when they are a baby, it is quite rare for adult cells to

Plant cells can differentiate for most of their lives, and they can also re-differentiate

Question 16

Where are adult stem cells produced and stored

Answer 16

bone marrow

Question 17

Where are plant stem cells produced

Answer 17

meristem

Question 18

What is the process of producing identical offspring called

Answer 18

cloning

Question 19

why is it easier to clone a plant

Answer 19

the cells can differentiate to form the required tissue

Question 20

what are the stages of life until an embryo

Answer 20

sperm and egg -> zygote -> embryo

Question 21

What is a zygote

Answer 21

a signle cell formed from the fusion of a sperm and egg

Question 22

What are some of the ways stem cells can be used

Answer 22

curing paralysis, insulin making cells, helping blindness, growing organs

Question 23

WHy is it important to clone plants

Answer 23

to produce identical plants reliable, economically, safely and quickly

Question 24

Where do most embryonic stem cells come from

Answer 24

aborted embryos

Question 25

What are some issues with using embryonic stem cells

Answer 25

- unethical - killing life - unreliable and unsafe - violation of rights - can cause cancer

Question 26

What are some benefits to using embryonic stem cells

Answer 26

- divide and grow rapidly - won't be rejected

Question 27

What are some negatives of using adult stem cells

Answer 27

- limited ability to differentiate - trigger immune responses

Question 28

What must be taken to prevent rejection of organs and cells

Answer 28

immunosuppressant drugs

Question 29

Where can we get embryonic stem cells from to overcome some of the ethical problems

Answer 29

in the unbilical cord and fluid around the foetus

Question 30

What does therapeutic cloning involve - what is the benefit

Answer 30

using adult cells to produce a cloned embryo of themselves - it would have perfectly matched embryonic cells for medical treatments