1. Prokaryotes and Viruses

2. Characteristics of Prokaryotic Cells
Single-celled bacteria and archaeans
No nucleus or membrane-bound organelles
Smallest, most widely distributed, numerous, and metabolically diverse organisms
Autotrophs and heterotrophs

3. Prokaryote Cell Shapes
Spheres (cocci), rods (bacilli), spirals (spirilla)

4. Prokaryote Cell Structures
Typical surface structures
Cell wall
Outermost protective capsule or slime layer
One or more flagella
Pili

5. A Prokaryotic Cell

6. Flagella and Pili

7. Prokaryotic Fission

8. Prokaryotic Cell Characteristics

9. The Bacteria The most common and diverse prokaryotes
Some are pathogens (cause disease in a host)

10. Food Poisoning

11. Bacterial Diversity: Cyanobacteria
Oxygen-releasing photoautotrophs
Chloroplasts probably evolved from ancient cyanobacteria by endosymbiosis

12. Bacterial Diversity: Gram-Positive Bacteria
Have thick walls
Endospores resist heat, boiling, irradiation, acids and disinfectants
Some are human pathogens

13. Bacterial Diversity: Chlamydias
All are intracellular parasites of animals
Obtain ATP from host cells
Some sexually transmitted diseases (C. trachomatis)

14. Bacterial Diversity: Spirochetes
Spring-shaped
Live on their own or in hosts
Some are pathogens

15. Archaean Physiology
Halophiles (salt lovers), extreme thermophiles, and methanogens (methane makers)

16. Archaeans in Extreme Environments

17. The Viruses
Viruses are noncellular infectious particles that cannot reproduce on their own
Viruses infect a host cell; their genes and enzymes take over the host’s mechanisms of replication and protein synthesis

18. Viral Structures

19. Prion Infections Prions
Proteins that occur naturally in the vertebrate nervous system, but can cause fatal disease when they misfold

20. Antibiotic Resistance
Use of antibiotics favors antibiotic-resistant bacteria
Genes that convey drug resistance can arise by mutation, may spread among members of the same or different species by conjugation

21. Protists – The Simplest Eukaryotes

22. An Evolutionary Road Map
Protists
The simplest eukaryotes
Most are single-celled
Some are multicelled and large

23. Protist Structure Protist cells have a nucleus (eukaryotes)
Most have one or more mitochondria
Many have chloroplasts that evolved from cyanobacteria or from another protist
Dominant stage of life cycle: Haploid or diploid

24. Protist Evolutionary Tree

25. Comparing Prokaryotes and Eukaryotes

26. Key Concepts: SORTING OUT THE PROTISTS
Protists include many lineages of single-celled eukaryotic organisms and their closest multicelled relatives
Gene sequencing and other methods are clarifying how protist lineages are related to one another and to plants, fungi, and animals

27. Ancient Flagellates Flagellated protozoans
Single-celled heterotrophs with flagella
Unwalled cells, pellicle retains shape
Most euglenoids live in freshwater
Some have chloroplasts that arose by secondary endosymbiosis from a green alga
Contractile vacuoles expel excess water

28. Disease-Causing Flagellates
Trichomonas vaginalis
Trypanosoma brucei

29. Shelled Amoebas Foraminiferans and radiolarians
Single-celled heterotrophs with a secreted shell
Many openings for pseudopods

30. Alveolates
All alveolates have tiny sacs (alveoli) beneath the plasma membrane
All single-celled
Examples:
Ciliates, dinoflagellates, and apicomplexans

31. Ciliates Aquatic predators and parasites with many cilia
Example: Paramecium

32. Dinoflagellates
Aquatic heterotrophs and autotrophs with a cellulose covering
Photosynthetic protists cause algal blooms in nutrient-rich water

33. Apicomplexans Heterotrophs: Parasites living in animal cells
Cell-piercing structure made of microtubules
Reproduce sexually and asexually in host cells
Only gametes have flagella
Example: Plasmodium (malaria)

34. Malaria
Plasmodium species cause malaria

35. Single-Celled Stramenopiles
Two flagella, one with hairlike filaments
Oomycotes
Heterotrophs (decomposers and parasites) that grow as a mesh of absorptive filaments
Some parasitic species are important plant pathogens

36. Photosynthetic Stramenopiles
Diatoms, coccolithophores, and golden algae
Often part of the phytoplankton
Photosynthetic cells (contain fucoxanthin)
Hard parts accumulate as mineral deposits
Coccolithophores (calcium carbonate plates): Chalk and limestone
Diatoms (silica shells): Diatomaceous earth

37. Stramenopiles of the Phytoplankton

38. Brown Algae Multicelled, photosynthetic stramenopiles
Include microscopic strands and giant kelps (the largest protists; ecological and commercial value)

39. Green Algae
Chlorophytes (most green algae) and charophytes (closest relatives of plants)
Have chloroplasts with chlorophylls a and b
Store carbohydrates as starch grains

40. Red Algae Most red algae are multicelled
Cultivated for commercial products

41. Amoebozoans Amoebas (single cells) and slime molds (“social amoebas”)
Heterotrophic, free-living

42. Slime Molds
Plasmodial slime molds
Feed as a multinucleated mass