Bacteria

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Bacteria

• Chapter 23

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Bacterial Classification

• Section 23.1

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REVIEW All Bacteria are Prokaryotes

• Prokaryotes
• Before nucleus
• No nucleus
• No membrane bound organelles

• Eukaryotes
• True nucleus
• Have nucleus
• Have membrane bound organelles

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Two Domains of Bacteria

• DIFFERENCES BASED UPON RNA MAKEUP
• Domain Bacteria
• Kingdom Eubacteria
• Domain Archaea
• Kingdom Archaebacteria
• More related to eukaryotes
• based upon rRNA gene comparison

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1. Domain Archaea

• Lack peptidoglycan (protein-carbohydrate
  compound) in cell wall
• Usually located in extreme conditions like
  swamps, salt lakes, and hot springs
• Three main types
• A. Methanogens
• B. Extreme halophlies
• C. Thermoacidophiles

Pyrodictium occultum is a  marine organism
commonly found in deep-sea hydrothermal vents.
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A. Methanogens

• Energy source from converting H2 and CO2 into
  methane gas.
• Live in areas absent of oxygen like swamps,
  sewage, and intestinal tract

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B. Extreme Halophiles

• Salt loving bacteria
• Location anywhere there is a high salt
  concentrations like the Great Salt Lake and the
  Dead Sea.
• Energy source salt need for them to make ATP

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C. Thermoacidophiles

• hot and acidic enviornments
• They are found in such places as acidic sulfur
  springs, undersea vents (smokers) and volcanoes

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2. Domain Bacteria

• Most abundant domain!
• Examples Cyanobacteria, chlamydia, Lyme
  Disease, botulism, TB, E. coli, anthrax,
  nitrogen-fixing bacteria
• Classified based on
• Gram stain
• Shape
• Biochemical properties

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Gram Stain

• Gram Positive Bacteria
• Simple cell wall with lots of peptidoglycan
• Stains purple

• Gram Negative Bacteria
• Complex cell wall with little peptidoglycan
• Stains pink

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Bacterial Shapes

• Spirilla (spiral-shaped)
• Bacilli (rod-shaped)
• Cocci (sphere-shaped)
• Streptococci long chains
• Staphylococci - clusters

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Bacterial Groups

1. Proteobacteria
2. Gram-Positive Bacteria
3. Cyanobacteria
4. Spriochetes
5. Chlamydia

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1. Proteobacteria

• Largest and most diverse group
• Many live symbiotically with other organisms
• Nitrogen-fixing bacteria
• Some cause diseases
• Rocky Mountain spotted fever
• Stomach ulcers
• Foodborne illnesses

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2. Gram-Positive Bacteria

• Some cause diseases
• Strep throat
• Botulism (Botox)
• Anthrax
• TB
• Leprosy
• A few make antibiotics that kill other bacteria

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3. Cyanobacteria

• Undergo photosynthesis for energy
• Simplest life requirements
• First oxygen-producing organisms on Earth!

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4. Spirochetes

• Gram-negative
• Spiral-shaped bacteria
• Examples syphilis Lyme disease

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5. Chlamydia

• Gram-negative
• Coccoid shaped, no peptidoglycan
• Causes a STD that lives inside animals

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Biology of Prokaryotes

• Section 23.2

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Bacterial Structures

• Most bacteria are composed of the following
  parts
• Outer cell wall
• Cell membrane
• Internal foldings thylakoids (photosynthesis)
• Cytoplasm
• Ribosomes
• DNA
• Small molecules and ions

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Endospores

• Can form in gram bacteria
• Thick-coated, resistant structures
• Form when environmental conditions are poor
• Resistant to high temp, strong chemicals,
  radiation, drying, etc.

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Prokaryotic Movement

• Taxis movement toward or away from stimuli
• Chemotaxis chemical stimuli
• Physical movement aided by flagella or slime
• Patterns of movement wave-like contractions or
  corkscrew rotation

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How do bacteria reproduce?

• Asexually via.
• Binary fission
• Budding
• permits the development of more complex colonial
  structures

Binary fission
Budding
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Genetic Recombination

• Three ways that bacteria can exchange and acquire
  new combinations of DNA
• 1. Transformation
• 2. Conjugation
• 3. Transduction

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1. Transformation

• When a bacteria takes on DNA from its external
  environment.
• Then this new DNA is substituted into the
  bacterial DNA

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2. Conjugation

• When two bacterium bind together and one
  bacterium transfers genetic information to the
  other.
• DNA channeled through the sex pilus

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3. Transduction

• Steps
• 1. Virus obtains a fragment of bacteria DNA from
  its host
• 2. Virus multiplies inside host (replicating the
  bacterial DNA as well)
• 3. Virus breaks out of host cell and invades new
  bacteria
• 4. New bacterial host will get old hosts DNA
  via the virus

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Know these parts of the bacteria!

• Cell Wall
• Outer Membrane
• Cell Membrane
• Cytoplasm
• Chromosome
• Plasmid
• Capsule Slime Layer
• Endospore
• Pilus
• Flagellum

p. 468
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Bacteria and Humans

• Section 23.3

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Bacterial Diseases

• Pathology The study of diseases
• Pathogens anything that causes disease
• Bacteria
• Viruses
• Fungi
• Protists

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Cholera attacking a cell
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Bacterial Poisons

• Toxins bacterial poisons that cause disease
• Exotoxins made up of proteins
• Secreted by the gram bacteria to surroundings
• Example tetanus
• Endotoxins made up of lipids and carbs.
• Released by dead gram bacteria
• Cause fever, body ache, weakness, and damage

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How to treat diseases

• Antibiotics fungi or bacteria that combat
  infection by interfering with various cellular
  functions
• May lead to Antibiotic Resistance
• Caused by not taking full dose of antibiotics

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Emerging Infection Diseases

• Zoonosis a disease that passes from wild animals
  to humans
• Increase due to global travel of humans
  destruction of natural habitat
• Example Lyme disease
• Other examples

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Useful Bacteria to Humans

• Probiotics- useful bacteria in your gut
• Recycle compounds from dead organisms
• Create organic compounds
• Food production (buttermilk, sour cream, yogurt,
  cottage cheese, sauerkraut, pickles)
• Produce fuels
• Insecticides
• Bioremdiation break down pollutants

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