U1 KA1- Division And Differentiation

Question 1

Define a somatic cell

Answer 1

Somatic cells are the differentiated cells that form the different types of body tissues that exist

Question 2

How do somatic cells reproduce

Answer 2

Mitosis

Question 3

Define Germline cells

Answer 3

A germline cell is one that eventually leads to the formation of gametes

Question 4

How do germline cells reproduce?

Answer 4

Germline cells undergo mitosis to produce more germline cells

Question 5

How to germline cells form gametes?

Answer 5

Germline cells undergo meiosis to produce gametes

Question 6

What is the process of meiosis?

Answer 6

During meiosis, genetic material is doubled by replication as before but in this process, the division leads to the formation of four nuclei, each of the four nuclei receives a set of 23 chromosomes, therefore forming for haploid gametes.

Question 7

What causes the formation of specialised cells?

Answer 7

The differentiation of unspecialised cells

Question 8

What is cellular differentiation?

Answer 8

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

During differentiation genes that express proteins, important for the function of that cell remain “switched on“

Question 9

When does a cell stop dividing?

Answer 9

Once a cell become specialised, it stops, dividing upon the expresses the genes characteristics for that type of cell

Question 10

Define stem cells

Answer 10

Unspecialised cells that have the ability to reproduce and differentiate into a diverse range of specialised cells

Question 11

Name the two types of stem cells

Answer 11

Embryonic stem cells and Adult (tissue) stem cells

Question 12

Where are embryonic stem cells found?

Answer 12

From an embryo about 4 to 5 days old (blastocyst)

Question 13

Why are embryonic stem cells able to differentiate into all cell types?

Answer 13

All genes in embryonic stem cells have the potential to be switched on.

Question 14

Embryonic stem cells are described as

Answer 14

Pluripotent

Question 15

What is the role of adult stem cells in the body?

Answer 15

Adult stem cells are involved in the growth, repair and renewal of cells found in tissue of the human body

Question 16

Adult stem cells have a much narrower differentiation potential than embryonic stem cells.

What does a “narrower differentiation potential “ mean?

Answer 16

This means adult stem cells produce a more limited range of cell types than embryonic stem cells

Question 17

Why do adult stem cells have a much narrower differentiation potential than embryonic stem cells?

Answer 17

Because many of their genes are already “switched off”

Question 18

Therapeutic uses of stem cells involve…

Answer 18

The repair of damaged or diseased organs

Question 19

Define in vitro

Answer 19

In a lab

Question 20

Give examples of stem cell therapies

Answer 20

• Bone marrow transplants are routinely used to treat cancer of the blood e.g. leukaemia
• Corneal damage can be repaired via grafting stem cells from the healthy eye to the damaged eye
• Stem cells can form skin grafts to treat burn patient

Question 21

How do you researchers use stem cells?

Answer 21

As a model cell to study how diseases develop or being used for drug testing

Question 22

Name an ethical issue to be considered while using stem cells

Answer 22

It is ending a potential life

Question 23

What is a cancer?

Answer 23

An uncontrolled growth of cells

Question 24

What causes the formation of a tumour?

Answer 24

When cells do not respond to regulatory signals and continue to divide excessively to produce a mass of abnormal cells, a tumour is formed

Question 25

Describe a benign tumour

Answer 25

The cancer cells remain in a discrete group in one location

Question 26

Describe the formation of a secondary tumour

Answer 26

When some of the cancer cells lose the surface molecules that keep them attached to the original cell group, they may enter the bloodstream and spread throughout the body