1. Ch 23: Bacteria Are prokaryotes: – Unicellular – No membrane-bound organelles (nucleus, ER, lysosomes) Live nearly everywhere… in/on other organisms, in ice, in hot springs, at the bottom of the ocean, in rocks, soil, air 2 main kinds: Eubacteria and Archaea

2. Archaea Live in extreme environments (temperature, pressure, chemicals (methane, salt)) Different: – Cell walls (more peptiodglycen (protein+ sugars)) – Lipids in cell membranes – DNA and RNA

3. Classifying Bacteria Shape:Colonies: – Round (coccus)Strepto (chains) – Rod (bacillus)Staphylo – Spiral (spirillum)(clusters)

4. Classifying Bacteria Gram stain – Stains outer wall, depending on structure – Gram +: purple, simple cell wall – Gram - : red, complex cell walls

5. Impact on humans: Proteobacteria: live in soil and make nitrogen usable by living things Gram +: cause disease (botulism, anthrax), make food (yogurt, sour cream), make antibiotics Cyanobacteria: makes oxygen, food for aquatic food chains Spirochetes: cause Lyme Disease and syphilis Chlamydia: STD

6. Structures and functions Outside: – Up to 3 layers: Cell membrane: lets things in and out Cell wall (different makeup than plants): structure Capsule (maybe): helps stick together – Movement: Flagella: long whip like tail, may have many Cilia: small hairs-like structures – Pili: small structures for reproduction

7. Structures and functions Inside – Cytoplasm: where most cell functions take place, since no organelles – Ribsomes: make proteins – DNA: in a loop Plasmid, small separate piece of DNA Getting oxygen: – Some bacteria have to have: ( obligate aerobes ) – Some have to not have ( obligate anaerobes ) – Some can live with or without ( facultative anaerobes )

8. Reproduction Asexually: Binary fission – DNA ring copies (2 only replication forks) and cell splits in two Sexually: – Conjugation: exchange DNA with another bacterium through pili – Transformation: take in DNA in environment (usu. from dead bacteria) – Transduction: get new DNA from a virus

9. Reproduction

10. Bacteria and Health Sometimes it releases chemicals while it’s alive ( exotoxins ), sometimes after it’s dead ( endotoxins ) Antibiotics: medicines that fight bacterial diseases. Make cell wall stop growing so bacterium “pops” Population can become resistance to antibiotics by mutation or by not finishing whole course of medications

11. Antibacterial Resistance

12. Good or bad? Bad: – AnthraxBotulismCholera – Tooth decayGonorrheaTetanus – Lyme diseaseSalmonellaE. coli – Staph infectionStrep throat Good: – Food: sour cream, cheese, yogurt, pickles, – Copy DNA for medicines – Fight pests (Bt) – Decompose – Nitrogen cycle

13. Ch 24: Viruses Not considered alive: – Don’t reproduce on own – don’t metabolize – don’t grow/develop – don’t perform homeostasis – don’t respond to environment

14. Structure/classification Vary greatly in structure/shape – DNA or RNA – Surrounded by capsid (protein coat) – Some surrounded by bilipid envelope Classified by: – DNA or RNA – Single or double strand – Linear or circular – Shape of capsid

15. Replication Viruses injects DNA/RNA, takes over the cell, makes the cell make more viruses, Kills cell when new viruses released infects more cells 2 cycles: – Lytic: happens fast, virus kills cells, virulent phages – Lysogenic: happens slow…days, weeks, months, years. Virus “hides” in the cell as part of cell’s genome, then enters lytic cycle, temperate phages

16. Lytic cycle Virulent phage: happens quickly – Viruses injects DNA/RNA – takes over the cell, makes the cell make more viruses – Kills the cell when viruses released to infect more cells

17. Lysogenic cycle Temperate phage: happens slowly…days, weeks, months, years. – Virus “hides” in the cell as part of cell’s genome – then enters lytic cycle and kills cells

18. Diseases & treatments Diseases: – Chicken pox/shinglesAIDS – HepatitisWarts – FluMeningitis – EbolaSARS – Bird Flu Treatments: – Vaccines: give inactive virus or parts of virus, helps immune system recognize and respond faster – Control vector: if spread by animal, kill animal – Antiviral drugs (few available)