2. Mention the characteristics
shared by all living organisms.
2. Explain the importance of
Maintaining the SA:V in a cell.

3. Multicellular organism have properties that emerge from the interaction of their cellular components
Inert gas

4. The cells by themselves aren’t much use
 The cells by themselves aren’t much use. It is the many cells working as a unit that allow the organs to perform their function.
Level of organization?

7. All living things are made up of basic units called cells.
Most of the billions of cells in the human body have one nucleus that acts as a control center, housing our 23 pairs of chromosomes.
A chromosome is a thread-like structure found in the cell’s nucleus, which can carry hundreds, sometimes thousands, of genes. In humans, one of each pair of 23 chromosomes is inherited from each parent.
The genetic material on these chromosomes is collectively referred to as the human genome.

8. Genes for example contain information that determines eye and hair color and other traits inherited from our parents.
Genes alone are not all-powerful. Most genes can do little until spurred on by other substances.
Genes basically wait inside the cell’s nucleus for other molecules to come along and read their messages.
These messages provide the cell with instructions for building a specific protein.

9. Cells in multicellular organisms differentiate to carry out specialized functions by expressing some of their genes but not others. 
All cells of an individual organisms share an identical genome - each cell contains the entire set of  genetic instructions for that organism.
The activation of different instructions (genes) within a given cell by chemical signals will cause it to differentiate from other cells like it.
Differentiation is the process during development whereby newly formed cells become more specialised and distinct from one another as they mature.

10. Differentiation
Differentiation is the process where cells become different, or specialized.
In differentiation, some genes are expressed, and not others
SOME cells divide and differentiate during embryonic development, and to some extent, as an adult these are called stem cells.
(so, stem cells can be used therapeutically to make replacement cells).

11. Can you think of
Some useful ways
Of using stem cells?

13. Where do we get stem cells from?
Stem cells can be derived from:
embryos or
the placenta
umbilical cord of the mother
also minimal amounts can be harvested from some adult tissue

14. Stem cells can be used to replace damaged or diseased cells with healthy, functioning ones.
This process requires:
The use of biochemical solutions to trigger differentiation into desired cell type
Surgical implantation of cells
into patient's own tissue
Suppression of host immune
system to prevent rejection of cells
Careful monitoring of new
cells to ensure they do not
become cancerous

15. Examples of therapeutic uses of stem cells:
1.  Retinal cells:  Replace dead cells in retina to cure diseases like glaucoma and macular degeneration
2.  Skin cells:  Graft new skin cells to replace damaged cells in severe burn victims
3.  Nerve cells:  Repair damage caused by spinal injuries to enable paralysed victims to regain movement
4.  Blood cells:  Bone marrow transplants for cancer patients who are immuno-compromised as a result of chemotherapy
5. Alzheimer's and parkinsonism are caused by loss of proper functioning brain cells studies are being done to try and cure this using stem cells.

16. Interactive tutorial about Stem cells
Summary of Stem cells
Stem cells
Stem cells (trachea)
Interactive tutorial about Stem cells

17. homework Questions on page 11 in your text book Why is it debatable?
Why do some cultures restrict the studies using stem cell therapy?