1. Cell Specialization

2. Why Specialize?
A single cellular organism performs all required functions in one cell.
e.g., Amoeba.

3. Why Specialize? Multicellular organisms are much more complex.
The body needs to supply food and nutrients, transport materials, remove wastes and fight infection.

4. Cellular Differentiation
The process of creating specialized cells.
All cells in the body originated from the zygote (fertilized egg) undergoing mitosis.
As an embryo develops, cells change their shape, contents and function.

5. Zygote – Blastula – Primary Tissue Layers(Germ Layers) – Specialized Tissue

6. Cellular Differentiation

7. What Causes Specialization?
1. Cytoplasm Differences:
Asymmetric distribution of organelles & other factors in zygote.
Results in different daughter cells.

8. What Causes Specialization?
Environmental Conditions:
Variations in temperature and nutrients.
Neighbouring Cells:
Substances produced by nearby cells can diffuse to nearby cells.

9. What Causes Specialization?
The factors listed may result in the expression of different genes within a cell.

10. Abnormal Development
Chemical contamination of the environment can affect cellular development.

11. Stem Cells
Cells that can differentiate into many different cell types.
The daughter cells have the same DNA, but different genes may be turned on or off.
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12. Types of Stem Cells Embryonic Stem Cells 2. Adult Stem Cells
Differentiates into any cell type.
2. Adult Stem Cells
Exists in some tissues but can only form specific types of cells.
E.g., bone marrow stem cells form white blood cells, red blood cells and platelets.

13. Stem Cell Research

14. Tissue Types
Tissues are a collection of similar cells that perform specific functions.
Animals have 4 types of tissue:
1. Epithelial.
2. Muscular.
3. Connective.
4. Nervous.

15. Epithelial Tissue Line the internal and external surfaces of the body.
Form a barrier by connecting adjoining cell membranes.

16. Muscular Tissue
Move the body or organ by contracting and relaxing.

17. Connective Tissue Strengthens, supports and protects other tissues.
Cells are in an extracellular matrix.

18. Nervous Tissue
Made of neurons with long projections that send and receive signals.
Coordinates body actions.

19. Tissues in the Arm

20. Specialized PLANT Cells