Cell structure can be observed under microscopes. Cells are the basic units of structure and function of living things. There are two main types of cells: prokaryotes which lack nuclei and organelles, and eukaryotes which have nuclei and organelles. The cell membrane controls what enters and exits the cell and is made of a phospholipid bilayer containing proteins. Major cell organelles include the nucleus which contains DNA, ribosomes which produce proteins, and mitochondria which generate energy.

1. Cell Structure

2. I. Looking at Cells A. Cells Under the Microscope-most cells are too small to be seen by the naked eye. 1. Robert Hooke - first to observe and name cells by looking at slices of cork . 2. Anton van Leeuwenhoek -first to observe living cells. 3. Magnification -quality of making an image appear larger. 4. Resolution -measure of the clarity of an image.

3. B. Types of Microscopes 1. Compound light microscope -uses two lenses to view living cells

4. 2. Electron microscope -very powerful; cannot view living cells.

5. II. Cell Features A. Cell Theory 1. All living things are made of cells. 2. Cells are the basic units of structure and function of living things. 3. Cells come from existing cells.

6. B. Prokaryote - “pro = no” cell without a nucleus or membrane-bound organelles . The simplest cells. Ex: Bacteria (has DNA, ribosomes, cytoplasm, and cell wall)

7. C. Eukaryote - “eu = true” true cells with a nucleus and organelles . Ex: plant and animal cells .

8. D. The Cell Membrane 1. Cell membranes are not rigid , they are fluid . 2. Function is to control what enters and exits the cell . Made of phospholipid bilayer that contains proteins .

9. III. Cell Organelles A. Nucleus -control center of the cell. Contains the DNA . B. Ribosomes -where proteins are made. C. Endoplasmic reticulum rough or smooth depending on whether it has ribosome. Transports proteins. D. Golgi Apparatus -package proteins from the e.r. E. Mitochondria -produces energy in the cell in the form of ATP .

10. Human cheek cell

11. Animal Cell-Draw

12. F. Plant Cell Structures 1. Cell Wall -helps provide support and maintain the shape of the plant cell. 2. Chloroplasts -plant cells only; where photosynthesis takes place. 3. Central vacuole -stores water and other substances.

13. Plant Cell-Draw

14. Onion skin slide