Human Cells: Division and Differentiation of Human Cells

Question 1

What is a somatic cell?

Answer 1

Any cell in the body other than cells involved in reproduction

Question 2

What type of cells are somatic cells?

Answer 2

They are diploid and contain two sets of homologous chromosomes

Question 3

What do diploid cells in humans have?

Answer 3

23 pairs of homologous chromosomes

Question 4

Somatic cells divide by what to form what?

Answer 4

Mitosis

More somatic cells

Question 5

What are germline cells?

Answer 5

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

Question 6

Germline stem cells divide by what?

Answer 6

Mitosis and meiosis

Question 7

Germline cells divide by mitosis and meiosis to produce what?

Answer 7

Divide by mitosis to produce more germline cells.

Divide by meiosis to produce haploid gametes.

Question 8

The nucleus of a germline stem cell can do what?

Answer 8

Divide by mitosis to maintain the diploid chromosome number

Question 9

The nucleus of a germline stem cell can divide by meiosis. What two divisions does it undergo?

Answer 9

Firstly separating homologous pairs of chromosomes.

Secondly separating pairs of chromatids.

Question 10

Haploid gametes in humans contain what?

Answer 10

23 single chromosomes

Question 11

What is cellular differentiation?

Answer 11

The process by which a cell expresses certain genes to produce proteins characteristic for that type of cell

Question 12

Cellular differentiation allows a cell to do what?

Answer 12

Carry out specialised functions

Question 13

What are stem cells?

Answer 13

Unspecialised somatic cells that can divide to make copies of themselves (self-renew) and to make cells that differentiate into specialised cells of one or more types

Question 14

What are the two types of stem cells in mammals?

Answer 14

Embryonic stem cells and tissue stem cells

Question 15

Embryonic stem cells are what? Meaning they can do what?

Answer 15

Pluripotent stem cells.

They can differentiate into all the cell types that make up the individual.

Question 16

What happens to all the genes in embryonic stem cells?

Answer 16

They can be switched on so these cells can differentiate into any type of cell

Question 17

What are tissue stem cells involved in?

Answer 17

The growth, repair and renewal of the cells found in that tissue

Question 18

Tissue stem cells are what? Meaning they can do what?

Answer 18

Multipotent stem cells.
They can differentiate into all of the types of cell found in a particular tissue type e.g. blood stem cells located in bone marrow can give rise to red blood cells, platelets, phagocytes and lymphocytes.

Question 19

What are the two types of uses of stem cells?

Answer 19

Therapeutic and research

Question 20

What do therapeutic uses of stem cells involve?

Answer 20

The repair of damaged or diseased organs or tissues

Question 21

What are therapeutic stem cells used in?

Answer 21

Corneal repair and the regeneration of damaged skin

Question 22

What can be done to embryonic stem cells?

Answer 22

They can be cultured in a laboratory to self-renew and provide a supply of embryonic stem cells

Question 23

What does the research use of stem cells involve?

Answer 23

Stem cells being used as model cells to study how diseases develop or being used for drug testing

Question 24

What does stem cell research provide?

Answer 24

Information on how cell processes such as cell growth, differentiation and gene regulation work

Question 25

Use of embryonic stem cells can offer effective treatments for diseases and injury; however it raises what?

Answer 25

Ethical issues because it involves the destruction of an early embryo

Question 26

Cancer cells divide excessively because they do not respond to what?

Answer 26

Regulatory signals

Question 27

The uncontrolled cell division of cancer cells results in what?

Answer 27

A mass of abnormal cells called a tumour

Question 28

Cells of the tumour may fail to attach to each other causing them to what?

Answer 28

Spread through the body where they may form secondary tumours