1. Chapter 23
Bacteria

2. Section 1 Vocabulary Pretest
Rod-shaped bacteria
Spiral-shaped bacteria
Sphere-shaped bacteria
Clusters of sphere-shaped bacteria
Chains of sphere-shaped bacteria
“Salt-loving” archaea
“Heat-living” archaea
Anaerobic archaea
Protein-carbohydrate found in bacterial cell walls
Appear reddish-pink when dyed
Appear purple when dyed
Cells w/ no nucleus
Prokaryote
Peptidoglycan
Methanogen
Halophile
Thermoacidophile
Bacillus
Coccus
Spirillum
Streptococcus
Staphylococcus
Gram-negative bacteria
Gram-positive bacteria

3. Answer Key Prokaryote L Peptidoglycan I Methanogen H Halophile F
Thermoacidophile G
Bacillus A
Coccus C
Spirillum B
Streptococcus E
Staphylococcus D
Gram-negative bacteria J
Gram-positive bacteria K

4. pROKARYOTES Most numerous organisms on Earth Found almost everywhere
Fossils date back 3.5 bya (first forms of life)
Single cells with no nucleus
Major source of food for many organisms
Important decomposers in the environment
Divided into two domains:
Domain Archaea
Domain Bacteria
Notice that Archaea are
more closely related to
Eukarya than to Bacteria and
thus share a more recent
common ancestor.

5. Domain Archaea Archaea = archaic (ancient)
Differ from other prokaryotes in the following ways:
Cell walls do not contain peptidoglycan
Have introns (portions of DNA that do not code for proteins)
Live in extreme environments
Different lipids in cell membranes
rRNA resembles rRNA of eukaryotes
Genes resemble genes of eukaryotes

6. Archaeal Groups Methanogens:
Convert hydrogen gas and carbon dioxide into methane gas.
Anaerobic
Live in muddy swamps, sewers, intestines of cows and termites

7. Halophiles: “Salt-loving” archaea
Live in very high salt concentrations (Great Salt Lake and the Dead Sea)
Owens Lake in CA.
The lake became
extremely salty when
the Owens river
was diverted to supply
water to LA. PPG
operated a soda ash
plant (seen in the
background)
for making glass. The
color is due to the
millions of halophiles
that now live in the lake

8. Thermoacidophiles:
Live in acid environments (pH <2) with very high temperatures (>230 degrees F).
Ex: Hot sulfur springs of Yellowstone National Park; deep water thermal vents (black smokers)

9. Domain Bacteria Unlike archaea, members of the domain bacteria:
Have cell walls with peptidoglycan
Have no introns
Live in a wide variety of environments
Have lipid membranes
rRNA is unlike rRNA of eukaryotes
Genes are unlike eukaryotes genes

10. Basic Shapes Bacteria come in a few basic shapes:
Bacilli (rod-shaped): streptobacilli (chains)
Cocci (sphere-shaped):streptococci (chains): staphylococci (clusters)
Spirilla (spiral-shaped)
Spirochaete (corkscrew)
Vibrio (comma-shaped)

11. Gram Stain
A staining technique called the gram stain illustrates a fundamental difference between two categories of bacteria: the gram positive and the gram negative bacteria.
Gram negative have complex cells walls with little peptidoglycan. They stain a reddish color.
Gram positive have simpler cell walls with a lot of peptidoglycan. They stain a purple color.

12. Bacterial Groups
Classifying bacteria based on evolutionary relationships has been difficult because bacteria can pick up genes from their environment through transformation.
Most scientists recognize the following groups:

13. Proteobacteria Proteobacteria: Very large and diverse group
Include: nitrogen-fixing bacteria that live in nodules inside the roots of legumes (peas, beans, alfalfa, and clover). These bacteria convert atmospheric nitrogen to ammonia, which plants can use.
Also includes some disease-causing bacteria such as rickettsia bacteria (causes Rocky Mountain Spotted Fever) and helicobacter pylori (causes stomach ulcers)
Also includes enteric bacteria (symbiotic bacteria that live in intestinal tracts of humans and animals)Ex: E. coli lives in our intestines and secretes vitamin K as well as assisting in the digestive breakdown of foods.
Other strands of E.coli and Salmonella cause food poisoning.
E.coli bacteria

14. Gram-Positive Bacteria
Gram-positive bacteria: will stain purple when gram stain is applied.
Examples include:
Streptococcus: causes strep throat
Clostridium botulinum: causes botulism also used in botox injections
Lactobacilli: sours milk; used in yogurt
Bacillus anthracis: causes anthrax
Actinomycetes: soil bacteria used to make many antibiotics

15. Cyanobacteria Cyanobacteria: photosynthetic bacteria
Earth’s first oxygen-producing organisms and are believed to be responsible for transforming Earth’s early atmosphere
Some grow in long filaments
Some form specialized cells called heterocysts which can fix nitrogen

16. spirochetes Spirochetes are gram-negative spiral-shaped bacteria.
Move with a corkscrew rotation
Can be free living or pathogenic
Ex: Treponema pallidum: causes syphilis
Borrelia burgdorferi: causes Lyme disease

17. Chlamydia
Chlamydia are gram-negative bacteria that live only inside animal cells.
There cell walls lack peptidoglycan
Ex: Chlamydia trachomatis: causes chlamydia (sexually transmitted disease) and trachoma eye disease, a leading cause of blindness.
Bacteria are the purple dots
inside a cell (pinkish brown)

18. Section 2 Vocabulary Pretest
Plasmid
Capsule
Glycocalyx
Pilus
Endospore
Heterotroph
Autotroph
Phototroph
Chemotroph
Obligate anaerobe
Facultative anaerobe
Obligate aerobe
Transformation
Conjugation
Tranduction
Sticky sugars found in bacterial capsules
Structure formed to survive harsh environmental conditions
Short, hair-like projection
One bacteria transfers DNA to another
Bacteria takes in DNA from its outside environment
Virus introduces DNA from one bacteria to another
Small, circular loop of DNA
Outer polysaccharide covering
Obtain carbon from CO2
Obtain carbon from other organisms
Get energy from light
Get energy from chemicals
Can live with or without oxygen
Must have oxygen
Must live without oxygen

19. Answer Key Plasmid G Capsule H Glycocalyx A Pilus C Endospore B
Heterotroph J
Autotroph I
Phototroph K
Chemotroph L
Obligate anaerobe O
Facultative anaerobe M
Obligate aerobe N
Transformation E
Conjugation D
Tranduction F

20. Structure and Function
General prokaryotic structure includes:
Capsule
Cell wall
Cell membrane
Cytoplasm
Ribosomes
DNA (nucleoid region)
Pili
Flagella

21. Cell Wall Cell wall Provides shape and protection
Made of peptidoglycan and lipopolysaccharides (only on gram negative)
Many antibiotics are designed to kill bacteria by breaking down the peptidoglycans of their cell walls. They are most effective on gram positive bacteria.

22. Cell Membrane
Also called the plasma membrane, the cell membrane controls what gets in or out of the bacteria cell.
Consists of a lipid bilayer and proteins
Contains catalytic enzymes for respiration and photosynthesis

23. DNA
DNA of prokaryotes consists of a single closed loop of double-stranded DNA
Located in a central area called the nucleoid region
Most bacteria also have small rings of DNA called plasmids
Self-replicate
Not necessary for cell survival
Often carry genes that allow bacteria to cause disease
Often carry genes that provide bacteria to become resistant to antibiotics

24. Capsules
Many bacteria have an outer covering of polysaccharides called a capsule
Their function:
Protection from drying out
Protection from phagocytic white blood cells
Fuzzy glycocalyx capsules allow bacteria to connect to host cells and tissues (often appears as a “halo” around stained bacteria cells

25. Pili
Pili are short, hairlike projections that help bacteria connect to each other and to host cells and other surfaces.
Can serve as a bridge to pass genetic material

26. endospores
Endospores form in gram-positive bacteria when environmental conditions become harsh.
They can resist high temps, strong chemicals, radiation, and drying out.
Cell copies its DNA and then forms a thick, protective covering around this copy. Most of the water is removed and the endospore becomes metabolically inactive. The rest of the cell will die, but the endospore, with its DNA cargo can remain viable for centuries.
It will reactivate when environmental conditions become favorable.
Can only be killed if heated to very high temperatures under pressure.

27. Prokaryotic Movement Some move by flagella
Movement toward or away from a stimulus is called taxis
Chemotaxis =response to chemical stimuli such as food or toxins.
Phototaxis =response to light

28. Nutrition and Metabolism
Two basic needs exist for prokaryotes:
Source of carbon
Source of energy
Two ways to obtain the carbon source:
Heterotrophs: obtain carbon from other organisms
Autotrophs: obtain carbon from CO2
Two ways to obtain the energy source:
Phototrophs: obtain energy from light
Chemotrophs: obtain energy from chemicals

29. Major Bacterial nutritional Modes
These needs can be used to divide prokaryotes into four nutritional groups:
Nutritional Mode
Energy and Carbon Source
Heterotroph
Photoheterotroph
Uses light energy but gets its carbon from other organisms
Chemoheterotroph
Obtains both energy and carbon from other organisms
Autotroph
Photoautotroph
Uses light energy and gets carbon from CO2
Chemoautotroph
Extracts energy from inorganic compounds and uses CO2 as a carbon source

30. Prokaryotic Habitats
Habitats occupied are based on biochemical abilities of different types of bacteria.
Oxygen requirements:
Obligate anaerobes cannot live in the presence of oxygen. Ex: Clostridium tetani
Facultative anaerobes can live with or without oxygen. Ex: E.coli
Obligate aerobes require oxygen to live Ex: Mycobacteriaum tuberculosis

31. Temperature requirements:
Psychrophilic prokaryotes: “cold-loving” grow well in oF. Can survive Antarctic temps by growing under the surface of rocks.
Mesophilic prokaryotes: grow well in moderate temperatures between oF.
Thermophilic prokaryotes: grow well in very hot temperatures between oF.

32. pH requirements: Most bacteria thrive in pHs between 6.5 and 7.5
Acidophiles are bacteria that thrive in low pHs (below 6)

33. Reproduction Usually reproduce by binary fission Asexual reproduction
DNA duplicates
DNA molecules move to poles
Cell divides
Two identical daughter cells are formed

34. Recombination
Recombination occurs when prokaryotes exchange pieces of DNA without reproduction.
Three ways recombination can occur:
Transformation —a prokaryote takes DNA from its outside environment.
Conjugation —two prokaryotes bind together and one cell transfers DNA to the other through a sex pilus.
Transduction —viruses transfer pieces of one prokaryotes DNA to another

35. Transformation often involves plasmids and restriction enzymes

36. Conjugation involves something called the F factor to be present in the donor cell.

37. Transduction involves defective bacteriophages that carry host DNA instead of viral DNA.

38. Section 3 Vocabulary Pretest
Pathology
Exotoxin
Endotoxin
Antibiotic resistance
Zoonosis
Bioremediation
Toxic substances made from lipids and carbs that are released after the cell dies.
Toxic substances secreted by bacteria into their environment
Evolution of pathogenic bacteria that antibiotics cannot kill
Study of diseases
A disease that can pass from animal to humans
Using bacteria to recycle compounds in nature

39. Answer Key Pathology D Exotoxin B Endotoxin A Antibiotic resistance C
Zoonosis E
Bioremediation F

40. Bacteria and Humans Roles of bacteria: Cause disease Food production
Nitrogen fixation
Decomposers
Bioremediation

41. Bacteria and Health Pathology —study of diseases
Pathogens: disease causing agents
Some bacteria cause disease by destroying body tissues. Ex: Streptococcus
Some bacteria cause disease by secreting toxins:
Exotoxins —toxins secreted by bacteria into their environment. Ex: Clostridium tetani secretes toxins that cause tetanus
Endotoxins —toxins released after the bacteria cell dies. They can cause fever, body aches, diarrhea, hemorrhage and weakness. Ex: E. coli

42. Antibiotics Antibiotics are substances used to kill bacteria.
Made naturally by some fungi and bacteria
Kill neighboring bacteria or fungi that compete for resources
Some (Penicillin) interfere with the formation of cell walls by breaking down peptidoglycans
Some (Tetracycline) interfere with protein synthesis

43. Antibiotic Resistance
Antibiotic resistance is the evolution of populations of pathogenic bacteria that antibiotics are unable to kill.
Because of over- prescription of antibiotics, many resistant genes are now on R-plasmids which can easily pass from one bacteria to the next by transformation.
This leads to multiple resistances to many antibiotics… Superbugs!

44. Emerging and Infectious Bacterial diseases
Most emerging diseases develop when infectious agents, such as bacteria, pass from wild animals to humans
Zoonosis —a disease that can pass from animal to human
Zoonotic disease are on the rise due to:
Human population growth
Global travel and trade

45. Food and Hygiene and bacteria
Foodborne illnesses result from the improper preparation, handling or storage of food.
To avoid:
Wash all raw fruits and vegetables
Wash hands and all utensils during food preparation
Refrigerate raw foods (eggs and lunchmeats)
Cook meat thoroughly
Refrigerate leftovers promptly

46. Methods of food preparation
Several methods can be used to prevent food spoilage by bacteria:
Foods can be dried and salted: Sausages and hams
Refrigeration: Milk and eggs
Adding large amounts of sugar: Jellies and jams
Pickling adds acids which slow bacterial growth: Pickles and relishes
Cooking at high temps: Meat products
Sealing and canning: canned foods
Adding preservatives: bread, juice and fruits

47. Bacteria and Industry Used in food production:
Buttermilk, sour cream, yogurt, cheeses, sauerkraut, pickles, coffee, and soy sauce
Used in chemical production:
Acetone, acetic acid, enzymes, antibiotics and insulin
Used to help break down sewage and added to laundry detergent to dissolve stains
Used in some pesticides
Used in bioremediation to breakdown pollutants
Used in recombinant DNA technology