U1 KA1- Division And Differentiation Flashcards
Define a somatic cell
Somatic cells are the differentiated cells that form the different types of body tissues that exist
How do somatic cells reproduce
Mitosis
Define Germline cells
A germline cell is one that eventually leads to the formation of gametes
How do germline cells reproduce?
Germline cells undergo mitosis to produce more germline cells
How to germline cells form gametes?
Germline cells undergo meiosis to produce gametes
What is the process of meiosis?
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.
What causes the formation of specialised cells?
The differentiation of unspecialised cells
What is cellular differentiation?
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“
When does a cell stop dividing?
Once a cell become specialised, it stops, dividing upon the expresses the genes characteristics for that type of cell
Define stem cells
Unspecialised cells that have the ability to reproduce and differentiate into a diverse range of specialised cells
Name the two types of stem cells
Embryonic stem cells and Adult (tissue) stem cells
Where are embryonic stem cells found?
From an embryo about 4 to 5 days old (blastocyst)
Why are embryonic stem cells able to differentiate into all cell types?
All genes in embryonic stem cells have the potential to be switched on.
Embryonic stem cells are described as
Pluripotent
What is the role of adult stem cells in the body?
Adult stem cells are involved in the growth, repair and renewal of cells found in tissue of the human body
Adult stem cells have a much narrower differentiation potential than embryonic stem cells.
What does a “narrower differentiation potential “ mean?
This means adult stem cells produce a more limited range of cell types than embryonic stem cells
Why do adult stem cells have a much narrower differentiation potential than embryonic stem cells?
Because many of their genes are already “switched off”
Therapeutic uses of stem cells involve…
The repair of damaged or diseased organs
Define in vitro
In a lab
Give examples of stem cell therapies
- 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
How do you researchers use stem cells?
As a model cell to study how diseases develop or being used for drug testing
Name an ethical issue to be considered while using stem cells
It is ending a potential life
What is a cancer?
An uncontrolled growth of cells
What causes the formation of a tumour?
When cells do not respond to regulatory signals and continue to divide excessively to produce a mass of abnormal cells, a tumour is formed
Describe a benign tumour
The cancer cells remain in a discrete group in one location
Describe the formation of a secondary tumour
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
