Division And Differentiation In Human Cells 1.1 Flashcards
What are the three groups that cells can be organised into
Somatic cells
Germline cells
Stem cells
What are somatic cells
Any cell in the body other than cells involved in reproduction
What are germline cells
Germline cells are gametes (egg and sperm)
What are stem cells
Cells that are undifferentiated (don’t have a specific role)
What are the two types of cell division
Mitosis and meiosis
What is mitosis and why is it important
Mitosis is the process of cell division. It is important because it provides new cells for growth and repair of damaged cells and maintains the diploid chromosome complement
What is meiosis
Meiosis is a special type of cell division involving 2 divisions resulting in haploid cells which have half the chromosomes of the parent cell
Mitosis vs meiosis: how many cell divisions
Mitosis = 1
Meiosis =2
Mitosis vs meiosis: how many daughter cells are produced
Mitosis = 2
Meiosis =4
Mitosis vs meiosis: compared to parent cell
Mitosis = identical
Meiosis = half the number of chromosomes
Mitosis vs meiosis: type of cell produced
Mitosis = somatic cells
Meiosis = germline cells
Somatic stem cells divide by mitosis to form ….
More somatic cells
Somatic cells
1.Is parent cell haploid or diploid ?
2.Type of cell division ?
3.Is daughter cell haploid or diploid ?
- Diploid
- Mitosis
- Diploid
Germline cells
1.Is parent cell haploid or diploid ?
2. Type of division ?
3. Is daughter cell haploid or diploid?
- Diploid
- Meiosis
- Haploid
Stem cells
1.Is parent cell haploid or diploid ?
2. Type of division ?
3. Is daughter cell haploid or diploid?
- Diploid
- Mitosis
- Diploid
What is cellular differentiation
Cellular differentiation is the process by which a cell expresses certain genes to produce proteins specific to that type of cell
Why does cellular differentiation occur
This occurs because certain genes are switched iff and certain genes are left switched in
What does cellular differentiation allow cells to carry out
Specialised functions
Function of muscle cells
Contract to allow us to move/allows movement
Function of nerve cells
Sends electrical impulses around the body
Function of sperm cells
Fuse with egg to produce a zygote
Function of red blood cell
Carries oxygen around the body
What is a negative of specialisation
Differentiated cells often lose the ability to make new copies of themselves
What are embryonic stem cells
Cells in the very early embryo can differentiate into all the cells types that make up the individual and so a pluripotent
What are tissue stem cells
Tissue stem cells are involved in the growth, repair and renewal of the cells found in that tissue. They are multipotent. Tissue stem cells are multipotent as they can differentiate into all of the types of cell found in a particular tissue type
Embryonic stem cells vs adult stem cells:
Found/location
Embryonic stem cells = embryo
Adult stem cells = tissue/bone marrow
Embryonic stem cells vs adult stem cells:
Gene expression
Embryonic = all are switched on
Adult = only some genes are switched on
Embryonic stem cells vs adult stem cells:
Differentiation into cell types
Embryonic = all cell types (pluripotent)
Adult = certain cell types (multipotent)
What are therapeutic uses of stem cells
Stem cells have already been used therapeutically to repair damaged or diseased organs, for example bone marrow transplants, corneal transplants and skin grafts for burns
Two types of therapeutic uses of tissue stem cells
Corneal transplant
Regeneration of damaged skin
What is corneal transplant
Corneal tissue is regenerated from stem cells then transplanted into patient
One issue of corneal transplant
Chance of rejection
What is regeneration of damaged skin (2)
- damaged skin can be regenerated using tissue stem cells
- skin cells can also be sprayed onto damaged skin and regenerated
Three issues with regeneration of damaged skin
Bad scarring
Risk of infection
Painful
Two types of research methods for stem cells
How diseases develop
Used for drug testing
A pro for using embryonic stem cells as research
Can offer effective treatments for diseases and conditions (such as type 1 diabetes)
A con for using embryonic stem cells for research
Destroys/leads to destruction of embryos
When a cell becomes cancerous is begins to grow and divide …..
Uncontrollably
Why do cancer cells divide excessively
Because they don’t respond to regulatory signals
How is a secondary tumour formed
Cells with in the primary tumour fail to attach to each other, spreading through the body
