1. Bacteria
UNIT 3 - Chapter 19

2. Prokaryotes Definition: single-celled organisms that lacks a NUCLEUS
OLD Classification – MONERA
Prokaryotes called BACTERIA
All BACTERIA were in the Kingdom – MONERA
CURRENT Classification
Prokaryotes (BACTERIA) are divided into 2 very different KINGDOMS
EUBACTERIA
ARCHAEBACTERIA

4. Eubacteria vs. Archaebacteria
BOTH: Prokaryotes, unicellular, autotrophic or heterotrophic
EUBACTERIA:
Larger kingdom
Cell Wall contains PEPTIDOGLYCAN
EX: E. coli and Streptococcus
ARCHAEBACTERIA:
Some similar DNA sequences to Eukaryotes (thought to be ancestors)
No PEPTIDOGLYCAN in cell wall
Live in EXTREME conditions (3 types):
Methanogens—poisoned by O2
Thermaphiles—live in extreme temps.
Halophiles—live in high saline

5. E. coli Eubacteria include a variety of lifestyles such as
are classified into the kingdoms of
Eubacteria
Archaebacteria
include a variety of lifestyles such as
live in harsh environments such as
Infecting large organisms
Thick mud
Living in soil
Animal digestive tracts
Salty lakes
Hot springs
E. coli
Methanogens

6. Shapes of Bacteria

7. Obtain and Use ENERGY AUTOTROPHS (make their food)
Photoautotrophs: use photosynthesis to make chemical energy out of sunlight
Found near lots of light
Chemoautrophs: get energy from inorganic chemical reactions
HETEROTROPHS (take in ORGANIC materials)
MOST PROKARYOTES
If food is not handled correctly, bacteria may eat it and in the process leave poisonous chemicals behind

8. Bacteria in Nature DECOMPOSERS “Natures Recyclers”
Help the ecosystem “Recycle” and break down dead matter into simpler substances
Works as sewage treatment; produces purified water; releases nitrogen and CO2
EXAMPLE: Nitrogen Fixation
Process by which nitrogen is converted into a form plants can use
Nitrogen gas (N2) must be change into ammonia (NH3)

9. Nitrogen-FIxers Rhizobium (bacteria)
Attached to the roots of soybeans and legumes
Convert nitrogen gas to ammonia
Ammonia helps plant (soybean)

10. Bacteria and Disease PATHOGENS (disease causing)
Cause disease by 2 methods
Damage TISSUES of organism
Mycobacerium tuberculosis
Cause Tuberculosis by breaking down lung tissue
Release TOXIN (poisons)
Salmonella and E. coli
Common types of food poison release toxins
Streptococcus
Causes strep throat releases toxin into the blood stream

11. Prevention and Treatment
Vaccines: dead or weakened pathogens (bacteria or viruses) used to induce formation of antibodies or immunity against the pathogen (must be given before)
Antibiotic: block growth and reproduction of bacteria (cure bacterial diseases)
Disease
Pathogen
Prevention
Tooth decay
Lyme disease
Tetanus
Tuberculosis
Salmonella food poisoning
Pneumonia
Cholera
Streptococcus mutans
Borrelia burgdorferi
Clostridium tetani
Mycobacterium tuberculosis
Salmonella enteritidis
Streptococcus pneumoniae
Vibrio cholerae
Regular dental hygiene
Protection from tick bites
Current tetanus vaccination
Vaccination
Proper food-handling practices
Maintaining good health
Clean water supplies

12. Human Uses of Bacteria FOOD PRODUCTION: cheese, yogurt, pickles,
INDUSTRIAL: digest oil, remove waste and poisons, synthesize drugs, genetic engineering
CONTROLLING BACTERIA
STERILIZTION: means of destroying
Heat (boiling water)
Chemicals (disinfectants)
INHIBITING or SLOWING growth
Refrigeration (low temps just slow)
Salt, Vinegar and sugar

13. VIRUSES
UNIT 3 chapter 19

14. Viruses STRUCTURE: CHARACTERISTICS:
Particles of Nucleic Acid (DNA, RNA), proteins, and lipids
CORE – contains DNA or RNA
CAPSID – outer protein coat
CHARACTERISTICS:
Many different sizes and shapes
Only REPRODUCE when infecting living cell (virus is not a cell)
Viruses are very specific

16. Review of Living and NON-living
8 Characteristics
Made of Cells
Reproduce
Based on Genetic Code
Grow and Develop
Obtain and use energy
Respond to environment
Homeostasis
Evolve
Viruses are considered NON-living. Why?

17. Viruses are NON-Living
NON-life like (contrasting)
Not made of cells
Do not reproduce independently
Do not Grow/Develop/Respond to environment
Do not Obtain and use energy
Life-like (comparing)
Evolve
Contain DNA or RNA

18. Viral Infections are Specific
Highly specific to type of cells they infect.
Plant viruses do not infect animal cells
Animal viruses only infect certain species of animals
BACTERIOPHAGES:
Virus that infects bacteria
EX: T4 and Lambda

19. Types of Viral Infections: LYTIC
Virus Enters cell and causes it to BURST Quickly!!!
Virus attaches to cell wall
Virus injects DNA into cell
Virus takes over cell metabolism and produces its own proteins & nucleic acids
Proteins and Nucleic acids combine to form NEW viruses
Enzyme breaks down cell wall & NEW viruses leave to infect other cells

20. Bacteriophage (virus) attaching Bacteria
Bacteriophage protein coat
Bacteriophage DNA
Bacterial
chromosome
Bacteriophage attaches to bacterium’s cell wall
Bacteriophage enzyme lyses the
bacterium’s cell wall, releasing
new bacteriophage particles that
can attack other cells.
Lytic Cycle
Bacteriophage injects DNA into bacterium
Bacteriophage proteins and nucleic acids assemble into complete bacteriophage particles
Bacteriophage
Bacteriophage DNA
Bacteriophage protein
Bacteriophage takes over bacterium’s metabolism, causing synthesis of new bacteriophage proteins and nucleic acids

21. Types of Viral Infections: LYSOGENIC
TWO Cycles
LYSOGENIC
LYTIC
DIFFERS from Lytic because…
DNA is embeded into host DNA
Virus does NOT KILL cell right away

22. Steps of LYSOGENIC Infection
Virus injects DNA
DNA forms a circle (Prophage)
DNA circle (prophage) combines with the bacteria DNA
Virus DNA (prophage) replicates with bacterial DNA
Virus DNA (prophage) exits bacterial DNA (forms own circle)
Begin Lytic cycle… New viruses Burst cell and leave

23. Lysogenic Infection Section 19-3
START: Bacteriophage injects DNA into bacterium
Bacteriophage DNA (prophage) can exit the bacterial chromosome
Bacterial
chromosome
Bacteriophage DNA
Lytic Cycle
Lysogenic Cycle
Bacteriophage DNA (prophage) may replicate with bacterium for many generations
Bacteriophage enzyme lyses the bacterium’s cell wall, releasing new bacteriophage particles that can attack other cells
Bacteriophage DNA forms a circle
Prophage
Bacteriophage proteins and nucleic acids assemble into complete bacteriophage particles
Bacteriophage DNA inserts itself into bacterial chromosome
Go to Section:

24. LYSOGENIC Cyle to LYTIC Cycle
Lysogenic cycle (latent or dormant)
The virus will switch to LYTIC cycle under ADVERSE conditions (Stress, radiation, chemical change)

25. Diseases:
Polio, Measles, Mumps, AIDS, Flu, Rabies, Yellow Fever, Colds
Lytic Infections
(colds-adenoviruses)
Lysogenic Infections (Herpes, EBV, HPV)
(Epstein-Barr EBV) Lytic-Mononucleosis / Lysogenic-predisposed to lymphoma
(HPV) lytic-genital warts / lysogenic cervical cancer
Retroviruses (RSV, HIV, HTLV, FLU)
Genetic material is RNA and makes copy into DNA
Retro- means “backwards”; develops mutations quickly
RSV (Rous sarcoma virus) can lead to sarcoma; HTLV can lead to leukemia… virus can transform/mutate host DNA

26. Human Viruses Nucleic Acid Type of Virus Diseases DNA RNA
Oncogenic viruses
Retroviruses
Adenoviruses
Herpesviruses
Poxviruses
cancer
cancer, AIDS
respiratory infections
Chickenpox, Mono
smallpox

27. WARNING
Following slides contain graphic pictures.
Herpes sores…

28. Herpes Simplex 1

29. Herpes Simplex II

30. Symptoms and Prevention
Best way to protect against a viral infection is PREVENTION
Vaccines (for some)
Only good before virus
Stimulates immune response
SYMPTOMS:
Caused when virus attacks and destroys body cells
Lytic cycle (see symptoms)
Lysogenic cycle (virus is dormant, no symptoms….but still contagious)

31. AIDS (Acquired Immune Deficiency)
CAUSED BY:
HIV (Human Immunodeficiency Virus)
Virus destroys helper T cells
EFFECTS:
Depresses cell-mediated immunity, Deficit in antibodies
Immune system turned upside down
Increasing frequency of infections, often rare types, Lesions on skin, Dementia
TRANSMITTED:
In body secretions (blood, semen, vaginal secretions)
Sexual Intercourse, use of IV needles, some documented cases by oral sex

32. HIV