B10 Cell division

Question 1

What are chromosomes made of?

Answer 1

DNA
Contain large number of genes

Question 2

What is a gene?

Answer 2

A section of DNA that codes for a protein

Question 3

How many chromosomes are found in a human body cell?

Answer 3

46 chromosomes

or

23 pairs of chromosomes

Question 4

How many chromosomes are found in a human gamete (sperm and eggs)

Answer 4

23

Question 5

What are the main stages of the cell cycle?

Answer 5

DNA replication
Mitosis
Cell division

Question 6

Name two types of cell division

Answer 6

Mitosis
Meiosis

Question 7

When is mitosis used?

Answer 7

Growth and repair
Produces genetically identical cells

Question 8

When is meiosis used?

Answer 8

Produce gametes (sperm and eggs)

Question 9

Describe what happens in mitosis

Answer 9

One set of chromosomes is pulled to each end of the cell

Nucleus dvides

Cytoplasm and cell membrane divide

Two genetically identical cells are made

Question 10

What happens in the cell before it divides?

Answer 10

Grows
Increase number of sub-cellular structures eg mitochondria, ribosomes etc.
DNA replicates

Question 11

What is a stem cell?

Answer 11

Undifferentiated cell which is capable of producing lots of identical cells by mitosis.

Question 12

What is special about the stem cells found in the embryo

Answer 12

Cells can be cloned
Cells can then differentiate into most different types of cell

Question 13

Name two conditions that could be treated by using embryonic stem cells.

Answer 13

Diabetes
Paralysis

Question 14

What is the function of stem cells in adult bone marrow?

Answer 14

Replace dead and damaged cells.
Eg blood cells

Question 15

What is the function of the stem cells in plant meristems?

Answer 15

Mitosis

Cells then differentiate into any type of plant cell

Question 16

What is therapeutic cloning?

Answer 16

Embryo is produced with same genetic makeup as patient.
These cells can be used to treat medical conditions
Cells will not be rejected by the patient

Question 17

What are the advantages of cloning plants using meristem stem cells?

Answer 17

Produce clones quickley and ecconomically

Can prevent rare plants becoming extinct
Produce large number of plants with favourable characteristics.
Produce identical plants for research

Question 18

What are the issues associated with the use of embryonic stem cells.

Answer 18

Stem cells obtained from aborted embryos - ethical and religious objection

Adult stem cells infected with virus could transfer infections to patients.

If donor stem cells are genetically different to patient it could cause rejection.

Development of stem cell therapies is slow, expensive and difficult