Discovery of Cells

• Cells- smallest unit of matter that can carry on all the processes of life.

Discovery of Cells

• Leewenhoek was one of first inventors of microscope and therefore one of first to describe microscopic organisms and living cells.

Discovery of Cells

• Hooke named them cells & influenced others to explore their existence.

The Cell Theory:

1. All living things are made of 1 or more cells

2. Cells are basic units of structure and function in an organism.

3. Cells come from preexisting cells.

The CellThere are 2 types of cells:

1. Prokaryotic

2. Eukaryotic

Prokaryotic Cells1. No nuclear membrane

2. No membrane bound organelles (except ribosomes!)

3. Found only in Kingdoms Eubacteria and Archaebacteria

4. Extremely small

Eukaryotic

1. Definite membrane bound nucleus

2. Contains membrane bound organelles

3. Found in Kingdom Animal, Plant, Fungi, & Protista

4. Slightly larger

Factors governing cell size

• Functions of the cells; More activity, more organelles, larger cells

• Surface area: Volume Ratio

(small animal, high metabolism)

Cell Organelles1. Nucleus- Control center of cell;

surrounded by a double-layered membrane. (Nucleolus= Houses DNA)

Cell Organelles

2. Golgi Apparatus- Shipping Plant. Flat membranous sacs (like pancake stack). Function: synthesis, storing, shipping materials.

Cell Organelles

3. Lysosomes- Garbage disposal & collection. Sacs full of disgestive enzymes. Some store food.

Cell Organelles

4. Vacuoles- Also digestive sacs. Pump out excess material, digestion, store food. Mostly in plants & protists.

Cell Organelles5. Mitochondria- Power plant. Location

where energy is produced (cell respiration). Double membrane (outer-smooth; inner-folded called cristae). Has own DNA

Cell Organelles

6. Chloroplast- Site of photosynthesis. Double membrane (outer-smooth; inner-stacks of coins call thylakoid membrane). Special plastid only in plant cells.

Sunlight + H20 + CO2 = Glucose + O2

Cell Organelles7. Cytoskeleton- Cell skeleton.

Support & movement. Microtubules (hollow) & microfilaments (solid). Cilia & flagella are special microtubules on the outside of cells for movement.

Cell Organelles

8. Ribosome- Protein Synthesis. Works w/ RNA. Small round organelles in cytoplasm & on endoplasmic reticulum.

Cell Organelles

9. Endoplasmic Reticulum- Highway of cell.

a. Rough ER- Has ribosomes. Protein synthesis and movement.

b. Smooth ER- lipid production & movement

Cell Organelles

10. Cell Wall- Made of cellulose. Only in plant and bacteria cells. Provides stability and framework.

Cell Organelles

11. Cytoplasm- liquid part of cell

12. Cell Membrane- Boundary of the cell. Semipermeable.

Cell Organelles

13. Centrioles- special microtubules that assist in mitosis (cell reproduction).

Centriole