1. Unit 9 Bacteria and Viruses

2. What are the characteristics of Bacteria?
Smallest and simplest living thing
Have no organelles, including no nucleus (meaning it’s a prokaryote, remember?!?)
Genetic material is in a simple circular chromosome
They do have cell calls that protect them from outside pressure.
They can be transmitted through air, water, human contact, contaminated food

3. Bacteria shapes Coccus: are round Bacillus: rod shaped
Spirillum: spirals

4. Arrangements
Diplo:Pairs
Staphylo: clusters
Strepto: Chains

5. Feeding Requirements Some are heterotrophs and live as parasites.
Some feed on dead material, called saprobes.
Some are photosynthetic and are autotrophs

6. Types of Metabolism Obligate anaerobes- killed in presence of oxygen.
Obligate aerobes: require oxygen to live
Facultative aerobes: can live with or without oxygen.

7. Reproduction Adaptations
Bacteria

8. Endospores
They are hard outer covering produced during harsh environmental conditions
Resistant to drying out and boiling.
Metabolism slows down inside the endospore while in the extreme environment.
Bacteria resumes growing when conditions are more favorable.

9. Toxin Production
As an endospore begins to grow, some bacteria produce poisons.
Some of these toxins are deadly. These toxins can also kill off other bacteria that are helpful
Examples: Botulism (food poisoning); tetanus (lock jaw)

10. Common Diseases Caused by Bacteria
Section 19-2
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
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11. Binary Fission
Reproduce asexually by splitting in half after copying DNA
This is a fast process.
Why will these bacteria stop reproducing?
Run out of food
Dry up
Poisoned by own waste

12. Conjugation
Sexual reproduction that transfers all or part of the DNA between 2 bacteria.
The sex pilli structure is used to transfer DNA.
When threatened the bacteria will choose to reproduce in this method.
**Conjugation is what makes bacteria resistant to changes, mainly because this is when mutations would occur in the DNA to cause these beneficial changes.

13. Helpful Uses
Nitrogen Fixation-some bacteria convert nitrogen gas into nitrates in the soil which is necessary for plant growth.
Saprobes: break down organic food/material

14. Helpful Uses
Food: food flavors are produced by fermentation and bacterial wastes. b. vinegar, yogurt, butter, cheese, pickles, buttermilk
Some bacteria even produce antibiotics that kill other bacteria
ONLY ANTIBIOTICS CAN KILL BACTERIA!!!!

15. Harmful Bacteria-
Pneumonia-inflammation of lungs(can be from a bacteria, virus, or fungus).
Conjunctivitis “Pink Eye ”
Infects outermost layer of eye(Conjunctiva)
can be viral(cold) or bacterial(staph or strep), or allergies
Contagious

16. Harmful Bacteria- Leprosy
Skin lesions , nerve damage
Mycobacterium
Difficult to transmit; Leper colonies not neccessary
100 cases a year in U.S.(south, Ca, Hawaii)
Have medicine now

17. Harmful Bacteria- Digestive
Stomach Virus (24 hour)- most of time it is not a virus but a bacteria from food poisoning.
Botulism- Food poisoning- Clostridium botulinum; endospore,
a. infants- don’t give homemade honey ; canning (boil at high temp)
b. Pasteurization- heating process to prevent contamination of milk.
3. Salmonella enterocolitis- infection in small intestine by Salmonella bacteria. Any food can have it.

18. Lyme Disease-Harmful Bacteria
Borrelia burgdorferi- transferred by a deer tick
Skin rash, inflammation, flu-like symptoms

19. Harmful Bacteria- Anthrax
Bacillus anthracis
Spore-forming
Occurs in cattle, sheep, humans
Inhale it or handle contaminated animal products
Symptoms show within 7 days

20. Harmful Bacteria-Skin
Diaper Rash- bacteria from feces
Scarlet Fever- skin rash- group A streptococci
3. Acne- oil blocks & bacteria grow

21. Harmful Bacteria- Respiratory
Strep Throat- infection of pharynx with Streptococcus. Spread-nasal or saliva
Sinusitis- inflammation of sinuses(hollow spaces within the bones around your nose)
Pertussis- Whooping Cough-like cold except coughing spells. Bordetella pertussis

22. Viruses

23. Characteristics of Viruses
Tiny, non-living particles
Do not respire, move or grow
Cannot reproduce on their own
Most reproduce inside of a host cell.
They can cause people to have infections that can last 7-10 days.
Viruses are not given Latin names; named for
Disease caused
Organ infected
Region detected in

24. Viral Structure Consist of 2 basic parts:
1. nucleic acid
2. protein coat
Capsid: protein coat containing inner core of DNA and RNA
They may have tail fibers and projections as structures to aid in attachment
Some have an extra outer layer called an envelope.

25. Viral recognition and attachment
Virus must recognize specific receptor site on host cell
Part of virus matches site on host
Lands on host and “locks in”
Attachment is specific: virus can enter and reproduce in only a few types of cells
Ex. HIV- WBC
Ex. Flu- Respiratory tract
Ex: tobacco mosaic virus- tobacco plant
Ex. T4 Bacteriophage- virus that infects bacteria

26. Examples of Viruses Influenza (bird flu; swine flu) HIV West Nile
ebola

27. Compare and contrast
Viruses vs. Living organisms

28. Viral Reproduction Viruses MUST reproduce inside a host cell.
They are classified as intracellular parasites.
Method of entry into host cell depends on the virus.
2 main types of viral reproduction:
1. lytic cycle
2. lysogenic cycle

29. Lytic Cycle
Viral DNA takes over host nucleus, produces new viruses, the cell fills with new viruses, at the end the cell bursts and dies! 

30. Lytic Cycle continued Attachment: virus attaches to cell surface.
Entry: injects DNA, takes over host nucleus
Replication: reproduces virus parts
Assembly: puts virus parts together into mature viruses
Lysis and release: cell splits open releasing viruses that can infect others.

31. Lysogenic Cycle Virus attacks cells, but does not kill immediately.
Viral DNA is mixed with host DNA like lytic cycle.
Does not immediately begin to reproduce, the host may function normally while viruses stay dormant.
Provirus can pop out at any time and begin reproducing.
Example: herpes-cold sores, fever blisters

32. Steps of Lysogenic cycle
Attachment: attaches to cell surface
Entry: DNA enters bacterial cell
Integration: DNA integrates into bacterial DNA
Replication: replicates when bacterial DNA replicates.