3. Cells rely on diffusion and osmosis to get the water, nutrients and other molecules necessary for life. All organisms get these from their external environment.

4. Internal environment - Extracellular spaces

5. What observations can you make based on the pictures below

6. So where do multicellular organisms get the specialized cells they need to maintain homeostasis?

7. The 100 or so cells in the blastocyst are known as embryonic stem cells.

8. Just like you are able to make many different types of bolts and screws from one block of metal...... all of the cells necessary for life come from these stem cells.

9. ... this process is known as cell differentiation The shape of the cell serves an important role in how it functions.

11. Root TissueStem Tissue Leaf Tissue

12. Epithelial cells (skin cells) like the ones in the picture above, are tightly packed together. How do you this works to protect our bodies?

13. But wait, don’t all of our cells have the same DNA in their nucleus? If that’s so, then how can different cells have different shapes In eukaryotic cells, DNA is packaged in the cell nucleus as chromosomes and chromosomes have sections that code for traits called genes