1. Lesson 1: Bacteria & Viruses
YouTube Videos:
Bozeman: Bacteria
Bozeman: Archaea

2. All living organisms must carry out these biological functions:
Movement (internal or external)
Metabolism & Excretion
Respiration
Circulation
Grow
Reproduce
Response

3. I. Introduction to Bacteria
E. Coli O157:H7 can make you very sick.
I. Introduction to Bacteria
Very small (1-5 mm), single-celled, prokaryotic living organisms
Were unknown until the development of the microscope
Can be found on most materials and surfaces
Billions on and in your
body right now
Streptococcus can cause strep throat.
This E. coli helps you digest food.
USDA NIFSI Food Safety in the Classroom©
University of Tennessee, Knoxville 2006

4. A. Classifying Prokaryotes
All are in kingdom Monera in the 5 Kingdom Classification System.
Are classified as either Eubacteria or Archaebacteria in the 6 Kingdom System.
Eubacteria
Characteristics:
Larger of the two, includes a wide variety of organisms, live almost everywhere.
Usually surrounded by a cell wall made of the carbohydrate, peptidoglycan, which determines its shape and protects it.
Ex: E. Coli

5. 2) Archaebacteria Characteristics:
Have cell walls that lack peptidoglycan, have membrane phospholipids that are different from the Eubacteria’s, and have genes that are more like those found in eukaryotic cells than in Eubacteria cells.
Can live everywhere, including organisms, like you, extreme environments like in Utah’s Great Salt Lake, or in hot springs, geysers, deep ocean vents, etc.

6. B. Identifying Prokaryotes
4 ways are:
by shape
chemical nature of their cell walls
the way they move
how they obtain energy.

7. 1) Shapes Three basic shapes
Bacilli
Three basic shapes
Rod shaped called bacilli
Round shaped called cocci
Spiral shaped called spirilla
Some exist as single cells, others cluster
together
Cocci
Cluster of Cocci
USDA NIFSI Food Safety in the Classroom©
University of Tennessee, Knoxville 2006
Spiral

8. 2) Chemical Nature of Cell Wall
Gram-staining is a method used to determine the type of cell wall.
Gram-positive = have thick peptidoglycan cell walls & stain dark purple.
Gram-negative = have thinner walls inside an outer lipid layer & stain pink or light red.

9. 3) The way they move Some do not move. Some use flagella Some snake
Some spiral forward
Glide on slimy secretions

10. 4) How they obtain energy?
Photosynthetic bacteria
Some make their own food from sunlight—like plants
Some are scavengers
Share the environment around them
Example: The bacteria in your stomach are now eating what you ate for breakfast
Some are warriors (pathogens)
They attack other living things
Example: The bacteria on your face can attack skin causing infection and acne
Harmless bacteria on the stomach lining
E. Coli O157:H7
is a pathogen
USDA NIFSI Food Safety in the Classroom©
University of Tennessee, Knoxville 2006

11. Heterotrophs
Chemoheterotrophs = take in organic molecules for energy and a supply of carbon.
Photoheterotrophs = Use sunlight for energy but also need to take in organic compounds as a carbon source.

12. B. Autotrophs
Photoautotrophs = use light energy to convert carbon dioxide and water to carbon compounds and oxygen.
Chemoautotrophs = Make organic carbon molecules from carbon dioxide but use energy from chemical reactions involving ammonia, hydrogen sulfide, etc. instead of sunlight.

13. 5) Respiration, Circulation & Excretion
Uses the process of diffusion to carry out each process.

14. 6. Growth & Reproduction Grow in number not in size
Humans grow in size from child to adult
2 factors that limit growth in bacteria:
Food availability & waste production
USDA NIFSI Food Safety in the Classroom©
University of Tennessee, Knoxville 2006

15. Reproduce by Binary Fission
In binary fission, the bacterium will double in size, replicate its DNA and then divide in half to make 2 bacteria (daughter cells).
Bacteria reproduce exponentially.

16. Conjugation
The process in which many bacteria exchange genetic information, increasing genetic diversity.
A hollow bridge forms between 2 bacterial cells & genes move from 1 bacterium to the other.

17. Spore formation
During unfavorable growth conditions, many bacteria form spores.
Endospore = a type of spore formed by bacteria producing a thick internal wall around its DNA & part of its cytoplasm.
These spores remain dormant until conditions become more favorable.

18. Lesson 3: Bacteria
C. Bacteria: The Good, The Bad & The Ugly

19. . Importance of Bacteria
Bacteria are vital to maintaining the living world. Some are:
producers that capture energy
some are decomposers
some fix nitrogen (Ex: N2  NH3)
some have other human uses (Ex: cleaning up oil spills, production of medications and food, production of vitamins in the human body, etc.)

20. A Closer Look – Helpful Bacteria
Pediococcus
- used in production of fermented meats
Lactobacillus casei – found in human intestines and mouth to improve digestion
Leuconostoc cremoris – used in the production of buttermilk and sour cream
Lactobacillus bulgaricus – used in the production of yogurt

21. What is a pathogen? Bacteria that make you sick are pathogens.
How do these bacteria make you sick?
They produce poisons (toxins) that result in fever, headache, vomiting, and diarrhea and destroy body tissue
USDA NIFSI Food Safety in the Classroom©
University of Tennessee, Knoxville 2006

22. Where do you get a pathogen?
Contact with people who are sick
Direct or indirect
Food, Water, or other Surfaces that are contaminated
Not all bacteria are pathogens.
Indirect contact
Foods that could be contaminated
USDA NIFSI Food Safety in the Classroom©
University of Tennessee, Knoxville 2006
Direct contact

23. Some are even helpful Examples of helpful bacteria:
Lactobacillus: makes cheese, yogurt, & buttermilk and produces vitamins in your intestine
Leuconostoc: makes pickles & sauerkraut
Pediococcus: makes pepperoni, salami & summer sausage
USDA NIFSI Food Safety in the Classroom©
University of Tennessee, Knoxville 2006

24. What are some common pathogens?
E. coli O157:H7
Pathogenic E. coli
(like O157:H7)
Found in ground beef, contaminated fruits and vegetables
Salmonella
Found in raw meats, poultry, eggs, sprouts, fruit and vegetables
Listeria
Found in deli foods, lunch meats, smoked fish and vegetables
Salmonella
Listeria

25. Examples of Pathogens
Salmonella
E. coli O157:H7
What shape are these bacteria? Cocci, bacilli, or spiral?
Staphylococcus aureus
Campylobacter jejuni
USDA NIFSI Food Safety in the Classroom©
University of Tennessee, Knoxville 2006

26. How can I avoid pathogens?
Wash your hands often so you won’t transfer bacteria to your mouth or food
Warm water with soap for 20 seconds, rub hard between fingers and nails
USDA NIFSI Food Safety in the Classroom©
University of Tennessee, Knoxville 2006

27. How can I avoid pathogens?
Cook food thoroughly to kill any pathogens that may be in your food
Store food properly to limit pathogen growth
Cold temperatures (40F)
USDA NIFSI Food Safety in the Classroom©
University of Tennessee, Knoxville 2006

28. Stained Bacteria Cells at 4x

29. Stained Bacteria Cells at 10x

30. Stained Bacteria Cells at 40x

31. Lesson 2: Viruses YouTube Videos
Bozeman: Viruses
Flu Attack! How a Virus Invades Your Body

32. II. Viruses What is a virus?
Virus = particles of nucleic acid, protein, and in some cases, lipids.
Wendell Stanley obtained crystals of tobacco mosaic virus. Since living organisms do not crystallize, he determined that viruses are not alive.

33. Viruses are also not considered alive because they are incapable of reproducing themselves.
They infect living cells and the cells reproduce them.
A typical virus is composed of a core of DNA or RNA surrounded by a protein coat.

34. capsid = a virus’s protein coat.
Has proteins that enable the virus to enter a host cell.
The cell then translates the viral genetic information into capsid proteins.
The cell transcribes and translates the viral genetic information.
Sometimes the cell makes copies of the virus, thus killing the host cell.

35. Most viruses are specific to the type of cell they infect.
Ex: Bacteriophage viruses only infect bacteria.

36. B. Viral Infection
Once inside the cell, one of two different processes can occur.
Lytic Infection = destroys the host cell immediately.
A virus enters a cell, the cell makes copies of the virus, and causes the cell to burst.

38. Lysogenic Infection = the host cell continues to make copies of the viruses.
A virus integrates its DNA into the DNA of the host cell and the viral genetic information replicates along with the host cell’s DNA.
Eventually, the host cell will burst.

41. Retroviruses HIV Virus Replication 3D Video
Retroviruses = viruses contain RNA as their genetic information.
Their genetic information is copied backwards: RNA to DNA
Ex: HIV (Human Immunodeficiency Virus)
HIV Virus Replication 3D Video

42. HIV invasion of a T-cell