1. Prokaryotes and Viruses

3. The Sizes of Microorganisms 1 µ m Eukaryotic Cells (10-100 µ m) Prokaryotic Cells (0.2-10 µ m) Staphylococcus Cyanobacterium Escherichia coli Viruses (0.05-0.2 µ m)

5. Three Common Bacterial Shapes (a) (b) (c)

13. Conjugation: Prokayotic “Mating” Sex Pilus Donor Recipient

16. The Prokaryote Flagellum (b)

19. Some Prokaryotes Thrive in Extreme Conditions

20. Nitrogen-Fixing Bacteria on Root Nodules (a) (b)

24. Viral Structure and Replication (a) Glycoproteins Envelope (lipid bilayer) Protein Coat Core Proteins Reverse Transcriptase Viral RNA in protein coat Spikes Herpes Viruses HIV (b)

25. Viruses Come in Many Shapes Rabies Measles Bacteriophage Herpes Tobacco Mosaic

29. Some Viruses Infect Bacteria Bacterium Newly forming bacteriophages

30. How Viruses Replicate: HIV (a) cytoplasm nucleus DNA vRNA mRNA 1a. Virus attaches to receptor 2. Viral reverse transcriptase makes DNA using viral RNA 1b. Core disintegrates; viral RNA enters the cytoplasm 3a. DNA enters nucleus & chromosomes 3b. DNA transcribed into mRNA & viral RNA, which move to cytoplasm

31. How Viruses Replicate: HIV (b) 4. Viral proteins made using mRNA 5. Viral proteins & RNA assembled 6. Viruses bud from plasma membrane

32. How Viruses Replicate: Herpes (a) (cytoplasm) envelope coat DNA nucleus DNA mRNA 1. Virus enters cell by endocytosis 3. Viral DNA transcribed to mRNA, which moves to cytoplasm 2a. Viral envelope merges with nuclear membrane 2b. Protein coat disintegrates; viral DNA copied & enters nucleus

33. How Viruses Replicate: Herpes (b) nucleus mRNA (cytoplasm) envelope coat DNA DNA mRNA 4. MRNA makes proteins, which enter nucleus 5. New viruses assembled & bud from nucleus, get envelope from inner nuclear membrane 6. Newly formed viruses leave the cell by exocytosis

38. Prions: Puzzling Proteins

39. The End