191Bacteria

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Section 19-1
CHAPTER Summary

• 191 Bacteria
• A. Classifying Prokaryotes
• 1. Eubacteria
• 2. Archaebacteria
• B. Identifying Prokaryotes
• 1. Shapes
• 2. Cell Walls
• 3. Movement
• C. Metabolic Diversity
• 1. Heterotrophs
• 2. Autotrophs
• 3. Releasing Energy

D. Growth and Reproduction 1. Binary
Fission 2. Conjugation 3. Spore
Formation E. Importance of Bacteria 1. Decomposer
s 2. Nitrogen Fixers 3. Human Uses of Bacteria
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BACTERIA Chapter 19

• How big are they?
• What are their structures?
• How do they eat and make energy?
• How do they reproduce?
• In general, what role do many bacteria play?
  (niche)
• What are some of the positive uses of bacteria?

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Concept Map
Section 19-1
Bacteria
are classified into the kingdoms of
live in harsh environments such as
include a variety of lifestyles such as
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• Eubacteria
• Prokaryotic
• More species
• Found everywhere
• Cell walls of peptidoglycan
• Archeabacteria
• Prokaryotic
• No peptidoglycan
• Different lipids in its membrane
• Found in harsh environments
• DNA sequences similar to eukaryotes

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• The domain Archaea
• Include prokaryotes that do not have
  peptidoglycan walls
• 3 major groups
• Methanogens
• Extreme halophiles
• Extreme thermophiles

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Methanogens

• Methanogens convert hydrogen and carbon dioxide
  into methane to generate energy anaerobically.
  Methanogens are obligate anaerobes they are
  killed by oxygen.
• Methanogens digest cellulose in cow and termite
  guts. Each cow belches 50 liters of methane a
  day. A major greenhouse gas.
• Methanogens are also in swamps, wetlands, and
  garbage dumps. (Garfield Shopping Mall)

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Halophiles

• Extreme halophiles. Grow in very salty
  conditions. Colorful bacteria in seawater
  evaporation beds, Great Salt Lake.
• Mostly aerobic metabolism.
• Some have a form of photosynthesis that uses
  bacteriorhodopsin, a pigment very similar to the
  rhodopsin pigment in our eyes. It is also called
  purple membrane protein

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Thermophiles

• Extreme thermophiles. Live at very high
  temperatures ocean hydrothermal vents (up to
  113o C, which would be boiling except for the
  high pressure under the ocean), hot springs in
  Yellowstone National Park.
• Use sulfur to generate energy just like we use
  oxygen donate electrons to sulfur to create
  hydrogen sulfide. Some generate sulfuric acid
  insteadthey live at very low pHs.

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Prokaryotic vs Eukaryotic vs Mitochondria and
Chloroplasts
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• Methods for Identifying and classifying
  microorganisms
• Morphological characteristics
• Differential staining
• Biochemical tests
• Bergeys Manual of Systematic Bacteriology- Used
  to identify microorganisms based on the results
  of these observations. The bible of bacterial
  identification.

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Basic Bacterial Shapes

• Three basic shapes
• Coccus
• Bacillus
• Spirilum
• Common Prefixes
• Diplo - two
• Tetra - four
• Staphylo - cluster
• Strepto - chain

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Bacterial morphologies (1)
Assorted Shapes
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What shape?
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What shape?
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• Appendages - flagella, pili
• Surface layers - capsule, cell wall, cell
  membrane
• Cytoplasm - nuclear material, ribosome, cytoplasm
• Specialized structure - endospore

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Section 19-1
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• Examples of bacterial flagella arrangement
  schemes.
• A-Monotrichous B-Lophotrichous
• C-Amphitrichous D-Peritrichous

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Bacterial Cell Wall

• Gram ()
• Those made up of peptidoglycan.
• (Appear blue/purple after staining)
• Gram (-)
• Those with little petidoglycan but a great deal
  of lipopolysaccharide.
• (Appear pink/red after staining)

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Gram-positive and gram-negative bacteria
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Gram Stain
(-)
( - )
()
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Differential Agar - Mannitol agar
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• Positive strep test Hemolysis of blood cells in
  sheep blood agar.

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• Capsule or slime layer
• Many bacteria are able to secrete material that
  adheres to the bacterial cell
• It consists of polysaccharide (and sometimes
  polypeptide) on bacilli. Most of them have only
  polysaccharide. It is a protective layer that
  resists host phagocytosis (process of engulfing).
  

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Bacterial capsule
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Capsules
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How do bacteria eat?
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How do bacteria breathe?- Obligate aerobe-
Obligate anaerobe- Facultative anaerobes
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Endotoxin VS Exotoxin

• Exotoxins Produced inside the bacterium and
  given off.
• Endotoxins Make up the bacteriums cell wall
  (some lipopolysaccharides in Gram (-))

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• Cytoplasm Structures
• 80 water, nucleic acids, proteins,
  carbohydrates, lipid and inorganic ions etc.
• 1. Bacterial chromosomes
• Single large circular double stranded DNA (no
  histone proteins)
• 2. Plasmids
• An extra loop of DNA found in some bacteria.
  Used in genetic engineering.

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Cytoplasm Structures (contd)

• 3. Ribosome
• Site of protein synthesis. (Amino acids linked
  together)

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Bacterial Reproduction

• Binary fission
• (What is it?)
• Conjugation
• (What does it accomplish?)
• Endospores
• (What is their advantage?)

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Spore Production (endospores)
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• Endospore stain B. cereus

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Two different stains showing endospores.
Closteridium tetani on the right.
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Growth of Bacteria

• Under ideal conditions, bacteria grow very
  rapidly some double in number every 20 minutes.
  
• Doubling in number 1-2-4-8-16- is exponential
  growth. It starts off slowly, but once going the
  number of bacteria increase very rapidly
• Usually some nutrient runs short, or waste
  material builds up, and growth ceases.
  Eventually a die-off occurs, reducing the number
  of live bacteria.

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Ideal conditions?

• Temperature
• Food
• Water
• No light (or light?)
• Oxygen (or no oxygen)

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Section Outline

• 192 Viruses
• A. What Is a Virus?
• B. Viral Infection
• 1. Lytic Infection
• 2. Lysogenic Infection
• C. Retroviruses
• D. Viruses and Living Cells

Section 19-2
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VirusesSize

• Here is how you can imagine the size of viruses
• If a virus was the size of a basketball
• A bacterium would be as large as a city block
• A grain of sand would be two miles long
• A person would be 4,000 miles tall

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Figure 19-9 Virus Structures
Tobacco Mosaic Virus
Influenza Virus
T4 Bacteriophage
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What Are Viruses Made Of?

• Viruses are composed of nucleic acid, proteins,
  and sometimes, lipids.
• Nucleic acid, which can be either DNA or RNA,
  encodes the genetic information to make virus
  copies.
• The nucleic acid is surrounded by a protective
  protein coat, called a capsid.
• An outer membranous layer, called an envelope,
  made of lipid and protein, surrounds the capsid
  in some viruses..

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• Lysogenic
• into the
• Lytic Cycle

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Figure 19-11 Viruses and Cells
Sectin 19-2
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Viroids Prions

• No capsid
• Strand of RNA
• Can reproduce inside cell

• No DNA or RNA
• No capsid.
• Only a protein (glycoprotein) that can enter
  into cells and cause disease

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Section 19-3
Section Outline
193 Diseases Caused by Bacteria and
Viruses A. Bacterial Disease in Humans 1. Using
Cells for Food 2. Releasing Toxins 3. Preventing
Bacterial Disease B. Bacterial Disease in
Animals C. Controlling Bacteria 1. Sterilization
by Heat 2. Disinfectants 3. Food Storage and
Processing D. Viral Disease in Humans E. Viral
Disease in Animals F. Viral Disease in
Plants G. Viroids and Prions 1. Viroids 2. Prions
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Common Diseases Caused by Bacteria
Section 19-3
Disease
Pathogen
Prevention
Tooth decay Lyme disease Tetanus Tuberculosis Salm
onella food poisoning Pneumonia Cholera
Streptococcus mutans Borrelia burgdorferi Clostrid
ium tetani Mycobacterium tuberculosis Salmonella
enteritidis Streptococcus pneumoniae Vibrio
cholerae
Regular dental hygiene Protection from tick
bites Current tetanus vaccination Vaccination Prop
er food-handling practices Maintaining good
health Clean water supplies
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Common Diseases Caused by Viruses
Section 19-3
Type of Virus
Nucleic Acid
Disease
Cancer Cancer, AIDS Respiratory
infections Chickenpox Smallpox
Oncogenic viruses Retrovirus Adenoviruses Herpesvi
ruses Poxviruses
DNA RNA DNA DNA DNA
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Retrovirus

• Possesses RNA rather than DNA
• HIV is a retrovirus
• Human Immune Deficiency Virus
• Acquired Immune Deficiency Syndrome

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Electron Microscope Pic of HIV
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CD4 Receptor

• (protein data bank)

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HIV Infection of T Helper Cell