1. Cytology Cytology The Study of Cells

3. Transmission EM Internal features Scanning EM Surface features Electron Microscopes • EM Drawbacks • Expense • B&W Images • Dead specimens

4. Why are cells so small? • Volume • The need to exchange materials is the same with one large or many small cells. • Surface Area • The ability to exchange materials is greater w/ small cells.

5. ½ 1 1 2 1 1 Increasing exchange • Cells alter shape to increase surface area (ability to exchange materials). SA = 7 (same V) SA = LARGE (same V) SA = 6

6. Cell Membrane • Phospholipid Bi-Layer • Selectively permeable • Small, nonpolar molecules pass easiest

7. Cell Membrane • Membrane Proteins • Assist passage of materials • Bind cells together • Enable cell recognition

8. Cell types • Eukaryotes • Animals, plants, fungi, protists • DNA enclosed in nuclear envelope • Membrane-bound organelles • Prokaryotes • Bacteria and Archaea • DNA not in nuclear envelope • No membrane-bound organelles

9. Nucleus • Nuclear Envelope • Membrane protects DNA • Pores allow passage of RNA • Nucleolus • Ribosome synthesis • Chromosomes • DNA + Proteins • Visible during cell division • Otherwise, indistinguishable (chromatin)

10. Nucleus

11. Organelles • Ribosome • Protein synthesis • No membrane • Endoplasmic Reticulum • Transport • Alterations

12. Organelles • Golgi Apparatus • Packaging and export of materials • Lysosome • Digestive sacs • Break down food, invaders, dead organelles

13. flagellum cilia Organelles • Cytoskeleton • Protein cell framework • Provides cell shape • Cell movement • Cell division

14. Plant Organelles • Cell Wall • Support/protection • Plants  Cellulose • Fungi  Chitin • Bacteria  Peptidoglycan • Chloroplast • Convert Light E  Glucose • Vacuole • Storage space • Contains water, waste, starch

15. Review Questions Complete these analogies • Volume : surface area :: cytoplasm : _______________ • Sundae : sprinkles :: rough endoplasmic reticulum : __ Which structure is dysfunctional? • Desirable materials are not able to enter the cell. • Engulfed food is building up in the cell. • The cell is unable to power any functions despite an ample food supply.

16. Review Questions Which structure? • Protein synthesis • Made of microtubules • Selectively permeable • Only found in plant cells • Makes ribosomes • Coiled up DNA