1. Biology Review Chapters 3 - 4  Key Concepts covered so far...

2. Looking at Cells  Microscopes enable biologists to examine cells in detail

3. Looking at Cells  Scientists use the metric system ( International System Measurement ) to measure the size of objects

4. Looking at Cells  Light microscopes have a low magnification and can be used to examine living cells

5. Looking at Cells  Electron microscopes have a high magnification but cannot be used to examine living cells

6. Looking at Cells  The scanning tunneling microscope uses a computer to generate three-dimensional images of objects

7. Cell Features  The cell theory has three parts All living things are made of one or more cells Cells are the basic units of structure and function in living organisms All cells come from other cells

8. Cell Features  Small cells function more efficiently than large cells

9. Cell Features  All cells have a Cell membrane Cytoplasm Ribosomes DNA

10. Cell Features  Prokaryotic cells lack internal compartments

11. Cell Features  Eukaryotic cells have a nucleus and other organelles, as well as a cytoskeleton of microscopic protein fibers

12. Cell Features  The lipid bilayer of a cell membrane is made of a double layer of phospholipid molecules

13. Cell Features  Proteins in cell membranes include ○ Enzymes ○ Receptor proteins ○ Transport proteins

14. Cell Organelles The nucleus of a eukaryotic cell directs the cell’s activities and stores DNA

15. Cell Organelles  In eukaryotic cells, an internal membrane system produces packages and distributes proteins

16. Cell Organelles  Mitochondria harvest energy from organic compounds to create ATP

17. Cell Organelles  Lysomes are small spherical organelles that contain the cell’s digestive enzymes

18. Cell Organelles  Plant cells have three structures that animals lack A cell wall Chloroplasts Central vacuole