1. Bell-Ringer
What is a virus? What are the characteristics of life? Is a virus living? Explain the structure of a virus. SPRING BREAK

2. Classification of Living Things
Taxonomy
Classification of Living Things

3. Three domains Archaea Eubacteria Eukarya “ancient” Unicellular
Prokaryotic (but not bacteria)
Found in most extreme environments
Eubacteria
Prokaryotic
Found in all parts of the world
Eukarya
Unicellular or Multicellular
Eukaryotic

4. Six kingdoms Domain Archaea Domain Eubacteria Domain Eukarya
Kingdom Archaea
Domain Eubacteria
Kingdom Eubacteria
Domain Eukarya
Kingdom Plantae
Kingdom Protista
Kingdom Fungi
Kingdom Animalia

5. Kingdom Archaea Extreme environment Anaerobic Photo/chemosynthetic
Heterotrophic

6. Kingdom Bacteria Unicellular Prokaryotes
Photo/chemosynthetic or heterotrophic

7. Cell structure

8. What are bacteria? Unicellular Circular DNA No organelles
E. Coli O157:H7 can make you very sick.
Earth’s oldest life forms – between 3.5 and 3.8 billion years old
Most abundant life form – up to 2.5 billion individual bacteria in 1 gram of fertile soil
Very adaptable – found in all of Earth’s ecosystems
Can be found on most materials and surfaces
Billions on and in your body right now
Unicellular
Circular DNA
No organelles
Streptococcus can cause strep throat.
This E. coli helps you digest food.

9. Shape

10. Bacterial Shapes 3 main shapes - coccus – sphere - bacillus – rods
- spirillum - spiral

11. Cocci
Bacilli
Spirilia
Cluster of cocci

12. Bacterial Structure: Cell Wall
Made of peptidoglycan – a combination of protein and polysaccharides
Some bacteria called Gram negative bacteria have an additional layer of membrane that contains lipopolysaccharide
- this extra layer inhibits the uptake of antibiotics – protecting the bacteria
cell wall
cell
membrane
cell
membrane
lipopolysaccharide
cell wall
Outer membrane

13. Gram + vs. Gram -
The type of cell wall is used by doctors to help diagnose disease
The bacteria are stained with a
special stain called Gram stain
Absorb stain appear purple
Bacteria without the extra membrane, appear purple. These are Gram positive (Gram +) bacteria
Named after Danish Scientist Hans Christian Gram – No Joke Gram was working on Pneumonia and discovered that different organisms took up stain differently. The process stains the both types of cells with crystal violet, and then they are treated with alcohol which
Bacteria with the extra membrane appear pink. These are Gram negative ( Gram -) bacteria
Don’t absorb stain appear
pink 13

14. Bacterial Characteristics
Metabolic diversity – Bacteria can produce energy in a variety of circumstance
Autotroph – (self-feeding) – some bacteria produce their own food
some use photosynthesis – get energy from light
some use chemosynthesis – get energy from chemicals
Heterotroph - (other feeding) – many bacteria are unable to produce their own food and are required to eat other things 14

15. Reproduction Binary fission (Asexual) Conjugation Spore Formation
Other:
Transformation
Transduction

16. Exchanging Genetic Information

17. Reproduction - Binary Fission
Bacterial cells undergoing binary fission 17

18. Cellular organism copies it’s genetic information then splits into two identical daughter cells

19. Conjugation- one cell passes a copy of its plasmid or chromosome to another
Recipient
Cell
Donor Cell
A special pilus forms
a connection called
a conjugation bridge
between 2 bacterial
cells
Plasmid
Conjugation bridge
The donor cell
copies its plasmid
or chromosome and
passes the copy
through the
conjugation bridge
Cells separate 19

20. Two organism swap genetic information such as how to be resistant to penicillin.

21. Spore Formation: Endospore
A type of dormant cell
Exhibit no signs of life
Highly resistant to environmental stresses such as:
-High temperatures
-Irradiation
-Strong acids
-Disinfectants

22. Transformation: Bacteria absorb “naked” DNA from the environment22

23. Transduction – DNA is carried from one bacteria to another by a virus23

24. Uses/benefits Today You come up with some!
Think of important tasks performed by bacteria that we’ve already studied!
Look it up!

25. Bacteria Play Important Roles in Ecosystems
Decomposers
– recycle dead organisms releasing their nutrients back to the environment for use by other organisms.
Without decomposers,
the elements on earth would have remained locked up in dead organisms and life would have ceased.

26. Bacterial Roles: Nitrogen Fixation
some bacteria contain enzymes which allow them to convert (or fix) nitrogen from the air into a useable form
- they are nitrogen fixing bacteria
- Why do living things use nitrogen?

27. Bacterial Roles: Producers
In some ecosystems
chemosynthetic and
photosynthetic bacteria
serve as the basis of
the food chain

28. Bacterial Roles: Symbiotic Bacteria
Many bacteria live in or on other organisms (including humans) and aid their host
- some live in the gut of herbivores helping to digest cellulose
- bacteria in the gut of humans
aid digestion and produce
vitamins
- bacteria on skin and in body
openings help prevent infection
by harmful organisms
Stomach bacteria help maintain stomach pH, produce B and K vitamins, studies show that babies given lactobacilius bacteria have less diarrhea

29. Bacterial Roles: Pathogenic Bacteria
Pathogens are agents that cause disease
- only a small portion of bacteria are pathogens
- most bacteria diseases are caused by toxins
released by the bacteria
- these toxins:
- poison cells and damage tissue
- interfere with cell signaling
- over-stimulate cells causing them to malfunction

30. Are all bacteria pathogens?
No, most are harmless
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

31. 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

32. 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

33. What shape are these bacteria? Cocci, bacilli, or spiral?
Examples of Pathogens
Salmonella
E. coli O157:H7
What shape are these bacteria? Cocci, bacilli, or spiral?
Staphylococcus aureus
Campylobacter jejuni

34. Antibiotics
Antibiotics are chemicals which either kill bacteria or prevent their growth and reproduction
Bacteria and other microbes produce antibiotics to reduce competition from other organisms
Penicillin was the first to be use to fight disease
- discovered accidently by Alexander Fleming in 1928
The discovery of antibiotics
revolutionized the treatment
of disease
Antibiotics which kill bacteria are bacteriacidal, the antibiotics which stop growth are referred to as bacteriastatic

35. Antibiotic Action
Antibiotics effect bacteria, but not eukaryotic cells
Antibiotics attack bacteria in 5 ways
- some damage the cell walls or prevent new cell wall from forming
- some damage the cell membrane
- some prevent protein synthesis
- some prevent DNA from being copied
- some interfere with bacterial metabolism
Bacterial ribosomes are 70S 50S and 30S subunits – antibiotics impact these subunits
Eukaryotic ribosomes are 80S 60S and 40S subunits – antibiotics don’t impact these

36. Antibiotic Resistance
Some bacteria have developed a resistance to the effect of some antibiotics
The number of resistant bacteria is growing.
The problem is increased by overuse and misuse of antibiotics.
- from the use of antibiotics to treat viral infections – Antibiotics don’t effect viruses.
- from the use of antibiotics in livestock (cattle, chickens, pigs) –Antibiotics show up in the meat and milk.
- Or, people take the antibiotics until they feel better, but stop before all of the bacteria are destroyed. This kills the most susceptible bacteria, but leaves the more resistant bacteria

37. Syphilis--Treponema pallidum/Bacterial
Causes an ulcer at the site of infection. 4 stages of life. Treatment now with Penicillin. 37

38. Mycobacterium leprae/Bacteria
Rod like Bacteria-spread through coughing and sneezing. In old days they thought it was genetic and they isolated people-Leprae colonies. Now (1940)there is antibiotic treatment to clear up the symptoms in 6-12 months. 38