Division & Differentiation in Human Cells

Division & Differentiation in Human Cells

1. What is Differentiation?

   • During embryological development the unspecialised stem cells of the early embryo differentiate into cells with specialised functions

2. What are Stem Cells?

   • Stem cells are unspecialised somatic cells that can divide to make copies of themselves & can differentiate into specialised cells of one or more types

3. How do Embryonic Stem Cells work?

   • Cells of the very early embryo, differentiate into all the cell types that make up an organism. They are said to be pluripotent.

4. How do Adult Stem Cells work?

   • Tissue stem cells are involved in the growth, repair and renewal of the cells found in that tissue. They are said to be multipotent

5. What are the main tissue types?

   • The main tissue types in the body are: apithelial, connective, muscle and nerve. The body organs are formed from a variety of these tissues.

6. What cells types do Multipotent haematopietic stem cells create?

   • Multipotent haematopietic stem cells in the red bone marrow give rise to all the cell types in the blood: red blood cells, platelets, and the various forms of phagocytes and lymphocytes

7. What do Tissues work together to create?

   • Tissues work together to form more complex organs, systems, and organisms such as humans.

8. How do somatic cells divide?

   • Somatic cells divide my mitosis to form more somatic cells, maintaining the diploid chromosome number.

9. What is Cellular Differentiation?

   • Cellular Differentiation is the process by which a cell develops more specialised functions by expressing the genes characteristic for that cell type.

10. What happens when the cell becomes differentiated?

    • Once a cell becomes differentiated it only expresses the genes that produce the proteins characteristic for that type of cell

11. How many pairs of chromosomes does a Germline nucleus contain?

    • The nucleus of Germline cells have 23 pair of chromosomes & are said to be diplopd.

12. How do Germline Cells divide?

    • Germline cells divide by mitosis to produce new germline cells (diploid).
      • Germline cells can also divide by meiosis to produce haploid gametes - these germline cells are known as Gamete Mother Cells.

13. Where are Gamete Mother Cells found and what do they produce?

    • Gamete Mother Cells are found in the sex organs and give rise to haploid gametes - Sperm & Eggs

14. What is the difference between mutations that occur in somatic cells & germline cells?

    • Mutations that occur in germline cells are passed to offspring whereas mutations in somatic cells will not.

15. What are stem cells used for?

    • Stem cell research provides information on how the cells processes such as cell growth, differentiation & gene regulation work.
      • Also used as model cells to study how diseases develop or for drug testing.

16. What are the therapeutic uses of stem cells?

    • The therapeutic uses include repair of diseased or damaged organs; by bone marrow transplants, skin grafts for burns & stem cells grafts for cornea repair

17. What happens if Cancer cells divide excessively?

    • Cancer Cells divide excessively to produce a mass of abnormal cells (a tumour) that do not respond to regulatory signals and may fail to attach to each other.
      • If the cancer cells fail to attach to each other they can spread throughout the body to form secondary tumours.