B2: Cell Division

Question 1

What are embroyonic stem cells?

Answer 1

The egg and sperm cell form a zygote- it divides and becomes a hollow ball of cells-embryo

The inner ball of these cells are called the embryonic stem cells.

Question 2

Why do cells divide my mitosis?

Answer 2

• to allow growth
• to repair bpdy tissues
• to replace old/dead/worn out cells

Question 3

What are the stages of the cell cycle?

Answer 3

• interphase
• mitosis
• cytokinesis

Question 4

What happens during the interphase?

Answer 4

• the cell grows in size
• DNA replicates
• organelles replicate

Question 5

What happens during mitosis?

Answer 5

• the replicated chromosomes line up along the centre of the cell
• the spindle fibres contract and the chromosomes get pulled to opposite poles
• the nucleus divides

Question 6

What happens during cytokinesis?

Answer 6

• cell membrane and cytoplasm divide

- 2 identical daughter cells are formed

Question 7

What are the products of mitosis?

Answer 7

2 genetically identical daughter cells

Question 8

What is a stem cell?

Answer 8

A cell that has not yet become specialised

Question 9

What ate the properties of a stem cell (2 answers)?

Answer 9

• can replicate many times

- has the potential to become specialised (any type of cell)

Question 10

Where are embryonic stem cells found?

Answer 10

Embryos

Question 11

Where are adult stem cells found?

Answer 11

Adult tissues such as bone marrow, brain, liver stem cells

Question 12

Where are stem cells found in plants?

Answer 12

• they are found in the meristems of a plant

- found in root and shoot tips

Question 13

What are the advantages of using embryonic stem cells to treat disease?(4 answers)

Answer 13

• potential to develop into any cell/tissue
• cells can become any type
• used to treat human diseases
• painless

Question 14

What are the advantages of using adult stem cells to treat disease(3 answers)?

Answer 14

• plentiful supply
• no ethical issues
• safer method(well tried/tested)

Question 15

What are the disadvantages of using embryonic stemm cells to treat disease?(2 answers)

Answer 15

• unethical (no consent)

- possible harm/ death to embryo

Question 16

What are the disadvantages of using adult stem cells to treat disease?( 4 answers)?

Answer 16

• painful to extract
• fewer diseases can be treated
• -can only form the type of cells from the tissue they were taken from
• infection risk during stem cell extraction

Question 17

What has stem cells been used to treat?

Answer 17

• paralysis
• Diabetes
• eyesight in the blind

Question 18

What is therapeutic cloning?

Answer 18

It involves an embryo being produced with the same genes as the patient

Question 19

What are the stages of theraputic cloning (6 steps)?

Answer 19

1. The nucleus from a human skin cell (doner) is removed and kept
2. Nucleus from a human egg cell is removed and discarded
3. Skin cell nucleus is inserted into the empty egg cell
4. Egg cell is given an electric shock to stop it from dividing
5. This develops into a embryo
6. The cells from this embryo are used to treat diseases

Question 20

Why is therapeutic cloning used?

Answer 20

So the stem cells produced are not rejected and may be used for medical treatment

Question 21

Stages of an evaluate Qs

Answer 21

Comparison 1
Comparison 2
Comparison 3(use data provided)

(Remeber to use works like whereas)

Balanced conclusion

Question 22

What is differentiation?

Answer 22

The process where a cell changes to become specialised for its job

Question 23

What is a ‘specialised cell’?

Answer 23

A cell that has a specific structure and performs a specific function

Question 24

When do animal cells lose the ability to differentiate?

Answer 24

They lose the ability to dofferentiate after they become specialised

Question 25

What type of cells can adult stem cells differentiate into?

Answer 25

They can only differenciate into cells from the type of tissue where they are found (liver stem cells can only beocme liver cells)

Question 26

What type of cells can embryonic cells differenciate into?

Answer 26

Almost every cell under the right conditions in a lab

Question 27

When do plant cells lose the ability to differentiate?

Answer 27

Stem cells (found in meristems) can differentiate into any type of plant cell throughout the plants entire life

Question 28

The stem cells in meristems can be used to_________

Answer 28

Make clones of the mature parent plant quickly and economically.

Question 29

Why are plant clones good?(3 answers)

Answer 29

It gives is a away of producing large numbers of rare plants reliably and safely

• we could save some plants from extinction by doing this
• it gives us a good source of reasearch
• it can get a large amount of crops resistant to disease.