Division And Differentiation

Question 1

What is a somatic cell?

Answer 1

A somatic cell is any cell in the body other than cells involved in reproduction

Question 2

How do somatic stem cells divide?

Answer 2

By mitosis

Question 3

When somatic stem cells undergo mitosis, what is the product?

Answer 3

More somatic cells with the same diploid chromosome complement

Question 4

What are germline cells?

Answer 4

Germline cells are gametes ( sperm and ova ) and the stem cells that divide to form gametes

Question 5

How do germline stem cells divide?

Answer 5

By mitosis and meiosis

Question 6

What organelle undergoes cell division?

Answer 6

The nucleus

Question 7

When germline stem cells divide by mitosis what is the product?

Answer 7

More germline stem cells

Question 8

How many pairs of chromosomes are in diploid cells?

Answer 8

23 pairs of homologous chromosomes, 2 sets.

Question 9

When a germline stem cells undergoes meiosis, what is produced?

Answer 9

4 haploid gametes

Question 10

What are the two divisions in meiosis? ( list steps )

Answer 10

Firstly, the homologous chromosomes are separated.
Secondly, the sister chromatids are separated, forming four haploid gametes.

Question 11

Define cellular differentiation.

Answer 11

Cellular differentiation is the process by which a cell expresses certain genes to produce proteins characteristic to that type of cell. * This allows a cell to carry out specialised functions *

Question 12

What are embryonic stem cells?

Answer 12

Embryonic stem cells are cells extracted from the early embryo / blastocyst

Question 13

What is characteristic of embryonic stem cells?

Answer 13

Embryonic stem cells can differentiate into all the cells that make up an individual and are therefore pluripotent.

Question 14

What is meant by pluripotent?

Answer 14

Pluripotent means a cell has the ability to express any gene, allowing the cell to differentiate into any type of cell that makes up an individual.

Question 15

What are tissue stem cells?

Answer 15

Tissue stem cells are stem cells found within a particular tissue.

Question 16

What are tissue stem cells involved in?

Answer 16

Tissue stem cells are involved in the growth, repair and renewal of the cells found in that tissue. Therefore they are multipotent.

Question 17

What is meant by multipotent?

Answer 17

Multipotent means a cell has the ability to differentiate into all of the types of cell found only in a particular tissue type. * Important Example * Blood stem cells located in bone marrow can give rise to red blood cells, platelets, phagocytes and lymphocytes.

Question 18

What is meant by therapeutic uses in regard to stem cells?

Answer 18

Therapeutic uses involve the repair of damaged or diseased organs or tissues

Question 19

Give 2 examples of therapeutic uses of stem cells.

Answer 19

Corneal Repair
Regeneration of damaged skin

Question 20

What are stem cells used for in research? ( 5 uses )

Answer 20

To study: * AS MODEL CELLS *
How diseases develop
Drug testing
Cellular differentiation
Gene regulation work
Cell growth

Question 21

What is a specific property of stem cells?

Answer 21

Stem cells have the ability of self-renew under the right conditions in a lab, and are also pluripotent.

Question 22

What is an ethical issue of using embryonic stem cells?

Answer 22

Extracting embryonic stem cells involves the destruction of embryos ( potential human life )

Question 23

What is a cancer cell?

Answer 23

A cancer cell is an abnormal cell that does not respond to regulatory signals, and therefore divide excessively, resulting in an abnormal mass of cells called a tumour.

Question 24

How are secondary tumours formed?

Answer 24

Cells from the initial tumour fail to attach to each other, therefore they spread throughout the body forming secondary tumours.

Question 25

What is the difference between normal cells and cancer cells?

Answer 25

Normal cells undergo apoptosis ( programmed cell death )
Cancer cells ignore these regulatory signals and divide excessively to form tumours.

Question 26

Why is it important that the chromosome complement is maintained?

Answer 26

To ensure that no genetic information is lost so that each daughter cell contains all of the characteristics of its species.