1. History of Cell Discoveries & Parts

2. 1. Robert Hooke’s microscope. a. He was the 1st to see cells in 1665.

3. Cork Cells

4. 2. 1673 Leeuwenhoek examined many types of cells.

5. 3. 1838 Schleiden all plants made of cells. 4
Schleiden all plants made of cells Schwann all animals made of cell. 5. Schwann wrote the cell theory: a. All organisms are made of one or more cells. b. The cell is the basic unit of life.

6. 6. 1858 Virchow saw cells dividing.
a. He added the third part of the cell theory. i. All cells come from cells.

7. 7. Cell Size: Better to be big or small?
a. Large cells
i. Chicken eggs are examples of large cells.
They do not need to take in nutrients.
ii. How would the amount of nutrients taken in determine size?

8. 8. Many small cells:
a. Reason most cells are so small is determined by taking food in and excreting waste through outer surface.
i. Larger the cell the more food it needs.
b. Larger the cell the more waste there is to excrete.

9. C. Surface area-to-volume ratio
i. As a cell’s volume increases so does it’s surface area.
1. Surface area-to-volume=
surface area_
volume
2. Volume grows faster.
3. If a cell gets too big it cannot take in enough nutrients fast enough or excrete waste fast enough.

10. 9. Parts of a cell
a. Cell membrane: surrounds cell i. Protective layer ii. Acts as a barrier iii. Separates the cell from the environment. b. Cytoplasm – fluid inside the cell

11. c. Organelles - structures that perform specific functions. i
c. Organelles - structures that perform specific functions. i. Different types of cells have different organelles. ii. Some are attached while others float.

12. d. Genetic material – All cells have DNA at some point. i
d. Genetic material – All cells have DNA at some point. i. DNA – deoxyribonucleic acid 1. Carries info needed to make new cells. 2. Passed from parent cells to new cells. 3. Found in the nucleus.