History of Cell Discoveries

& Parts

1. Robert Hooke’s microscope.

a. He was the 1st to see cells in

1665.

Cork Cells

2. 1673 Leeuwenhoek examined many types of cells.

3. 1838 Schleiden all plants made of cells.

4. 1839 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. 1858 Virchow saw cells dividing.

a. He added the third part of the cell theory.i. All cells come from cells.

7. Cell Size: Better to be big or small?a. Large cells

i. Chicken eggs are examples of large cells.1. They do not need to take

in nutrients.ii. How would the amount of

nutrients taken in determine size?

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.

C. Surface area-to-volume ratioi. As a cell’s volume increases so does it’s

surface area.1. Surface area-to-volume= surface area_ volume2. Volume grows faster.3. If a cell gets too big it cannot take in

enough nutrients fast enough or excrete waste fast enough.

9. Parts of a cella. Cell membrane: surrounds cell

i. Protective layer ii. Acts as a barrieriii. Separates the cell from the

environment.b. Cytoplasm – fluid inside the cell

c. Organelles - structures that perform specific functions.i. Different types of cells

have different organelles.ii. Some are attached while

others float.

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.