B2 Cell Division

Question 1

What is differentiation?

Answer 1

Process by which cells become specialised and adapted to carry out a particular function

Question 2

How do you make a plant clone?

Answer 2

To make a plant clone, you take some plant tissue and place it in a petri dish with nutrients and then plant the plantlet in soil

Question 3

What are stem cells?

Answer 3

Stem cells are unspecialised cells that can develop into many other types of cells

Question 4

Where are stem cells found?

Answer 4

Stem cells are found:
- Bone Marrow or some other organs (adult stem cells)
- Embryo (Embryonic)
- Shoot / root tips (Meristems)

Question 5

What does a sperm and egg fuse to form?

Answer 5

Zygote

Question 6

What does a zygote do?

Answer 6

It divides forming a hollow ball of cells

Question 7

What is the definition of growth?

Answer 7

Growth is the process of cell division followed by cells becoming specialised

Question 8

What are the stages in the cell cycle?

Answer 8

Stage 1: copies of the DNA are made
Stage 2: Nucleus divides
Stage 3: Cell divides into two

Question 9

The mass of DNA in a human body cell at the start of the cell cycle is 6 picograms.
What mass of DNA will be in each of the new cells produced by this cell division?

Answer 9

6 picograms

Question 10

Stem cells are undifferentiated cells.
Name a correct statement?

Answer 10

Meristem cells in plants can differentiate throughout the life of the plant

Question 11

What are two advantages of therapeutic cloning?

Answer 11

• may cure/treat diseases
• cells /tissues of any type can be produced

Question 12

What are two disadvantages of therapeutic cloning?

Answer 12

• poor success rate
• potential life is killed / destroyed

Question 13

Name one source of human stem cells, other than human embryos (part(i))

Answer 13

Bone marrow

Question 14

Give one advantage of using stem cells from embryos, compaed with cells from the source named in part (i)

Answer 14

Cells will not be rejected by the oatient’s body

Question 15

Give one place in a plant where stem cells are found

Answer 15

Meristem(s)

Question 16

What is one economic use of plant stem cells?

Answer 16

To produce large numbers of identical plants

Question 17

What happens in each stage of the cell cycle

Answer 17

1) Interphase
• DNA replicates.
• Mitochondria and
ribosomes replicate.
• Cell increases in size.
2) Mitosis
• Chromosomes line up along centre of the cell.
• Spindle contracts.
• Chromosomes get pulled to opposite ends of the cell.
• Nucleus divides (into two nuclei).
3) Cytokinesis:
• Cytoplasm and cell membrane
divide.
• 2 new identical cells are
formed.

Question 18

Give two advantages of therapeutic cloning in medical treatments

Answer 18

May cure / treat diseases

Question 19

Give two disadvantages of therapeutic cloning in medical treatments

Answer 19

(Potential) life is killed / destroyed

Question 20

Name two advantages of embryonic stem cells

Answer 20

• can treat a wide variety of diseases
• can become any cell type

Question 21

Name two advantages of adult stem cells

Answer 21

• No ethical issues as adult can give consent
  for the stem cells to be collected.
• Safer, as this is a well-tested method.

Question 22

Name two disadvantages of embryonic stem cells

Answer 22

• Possible harm/death of the embryo.
• Human rights/ethical issues (the
  embryo cannot give consent).

Question 23

Name two disadvantages of adult stem cells

Answer 23

• Possibility of infection during extraction of
  stem cells.
• Adult stem cells can only become one type
  of cell (same as the tissue it came from).

Question 24

What is the definition of therapeutic cloning?

Answer 24

Therapeutic cloning is a process of creating stem cells with the same genes as the patient. This would prevent rejection.

Question 25

What is the process of therapeutic cloning?

Answer 25

1. Nucleus taken out of a human egg cell (and is discarded).
2. Isolate nucleus from a patient’s cell (e.g. a skin cell) is inserted into the empty egg cell.
3. Egg cell stimulated (by an electric shock) to divide develop into an embryo.
4. Embryonic stem cells are taken from the embryo after 4-5 days.
5. Stem cells grown in a container of warm nutrients.
6. Stem cells treated to develop into required cell types for a patient.

Question 26

What is the defintion of adult stem cells?

Answer 26

Stem cells that are found in adults that can differentiate and form a limited number of cells

Question 27

What is the definition of cell cycle?

Answer 27

The three-stage process of cell division in a body cell that involves mitosis and results in the formation of two identical daughter cells

Question 28

What is the defintion of cloning?

Answer 28

the production of identical offspring by asexual reproduction

Question 29

What is the definition of defferentiate?

Answer 29

the process where cells become specialised for a particular function

Question 30

What is the definition of embryonic stem cells?

Answer 30

stem cells from an early embryo that can differentiate to form the specialised cells of the body

Question 31

What is the definition of mitosis?

Answer 31

part of the cell cycle where one set of new chromosomes is pulled to each end of the cell forming two identical
nuclei during cell division

Question 32

What is the definition of stem cells?

Answer 32

undifferentiated cells with the potential to form a wide variety of different cell types

Question 33

What is the definition of therapeutic cloning?

Answer 33

a process where an embryo is produced that is genetically identical to the patient so the cells can then be used in
medical treatments

Question 34

What is the definition of zygote?

Answer 34

the single new cell formed by the fusion of gametes in sexual reproduction