Microbiology : Unit

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Microbiology Unit 2 Bacteria

• Bacteria are small living organisms found almost
  everywhere on the earth.
• Bacteria are prokaryotes which are typically
  unicellular.
• Bacteria are classified into the monera kingdom.

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Classification of Bacteria

• Bacteria are classified into two major groups
  archaebacteria and eubacteria.
• Archaebacteria live without oxygen, and obtain
  their energy from inorganic compounds.

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Archaebacteria

• Archaebacteria can survive and thrive in harsh
  environments.
• Examples of archaebacteria include
  methane-producting bacteria in cows stomachs,
  salt-loving bacteria, and heat and acid loving
  bacteria which thrive in hot springs.

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Archaebacteria

• Archaebacteria found in the stomachs of cows
  allow for the cow to break down and digest the
  cellulose in plant cells. These bacteria help
  cows turn cellulose into glucose. The bacteria
  produce methane gas in this process.

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Eubacteria

• Eubacteria display a wide array of habitats and
  metabolism. Eubacteria are divided into groups
  including
• Heterotrophs
• Photosynthesic Autotrophs
• Chemosynthetic Autotrophs

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Eubacteria

• Eubacteria differ from Archaebacteria in
  differences of cell walls, plasma membrane, and
  sequence of DNA bases.

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Eubacteria

• Most common bacteria are classified as
  eubacteria.
• Eubacteria include the phostosynthetic bacteria
  called cyanobacteria. Cyanobacteria include many
  different colors, based upon the pigments they
  contain to trap sunlight to make their own food.

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Bacteria Structure

• Bacteria have different shapes and structures,
  but a structures found in bacteria include
• Flagella (some)
• Capsule (some)
• Cell wall
• Plasma membrane
• DNA
• Pili (some)

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Bacteria Structure/Function

• Flagella allows movement
• Pili extensions of plasma membrane, help
  sticking
• Plasma membrane lipid layer
• Capsule extra barrier (gelatinous), bacteria
  with capsules are more likely to cause disease.
• DNA genetic material for the cell
• Cell Wall rigid, protection for cell, different
  composition with different bacteria.

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Bacteria Shapes

• Most bacteria are found in colonies.
• Bacteria can be round, spiral, or rod shaped.
• Round coccus
• Spiral spirillum
• Rod bacillus

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Bacteria Groups

• Bacteria are also classified into the shape of
  groups or colonies they form.
• Diplo paired cells
• Staphylo grapelike clusters
• Strepto long chains

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Journal Activity 1

• Using the website below answer the following
  questions
• 1) Describe archaea microbes, and the
  thermophiles, halophiles, methanogens, and
  psychrophiles.
• Name two different bacteria found in the Friend
  or Foe section of the website. Include its
  function and other information you can gather
  about it.
• http//www.microbe.org/index.html

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Journal Activity 1

• Describe the work that Ali S. Khan does as an
  epidemiologist. Include a brief description of
  the outbreak of a virus in 1993 in the Southwest
  U.S. ( Careers tab)

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Bacteria Metabolism

• Most bacteria require oxygen to metabolize.
  These bacteria are called obligate aerobes.
• Bacteria which dont use oxygen, and are killed
  by it are termed obligate anaerobes.

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Endospores

• Some bacteria when faced with unfavorable
  conditions form an endospore. An endospore has a
  hard outer covering which is resistant to drying
  out, or temperature, etc.
• When conditions are favorable the endospore
  germinates and reproduces.

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Botulism

• One group of bacteria called clostridia, can form
  endospores. Clostridium botulinum, produces a
  toxin. If canned food is not properly sterilized
  these endospores can become active inside a can
  and the disease botulism can occur.

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Bacteria Reproduction

• Bacteria reproduce by the process of binary
  fission.
• Binary fission involves the copying of the DNA
  and the splitting into two new cells.

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Bacteria Reproduction

• Under optimum conditions bacteria can reproduce
  every 20 minutes.
• Bacteria reproduction is controlled by various
  factors including temperature and food
  availability.

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Conjugation

• Some bacteria can reproduce sexually in a process
  called conjugation.
• In conjugation one bacteria is able to transfer
  its DNA into another bacteria by means of a pilus
  (pili)

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Journal Activity 2

• Use the website below to describe the following
  bacteria. Include the shape and other
  information
• Escherichia coli 0157H7
• Staphylococcus aureus
• Salmonella enteritidis
• Clostridium tetini
• http//www.cat.cc.md.us/gkaiser/goshp.html

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Bacteria- Cell Wall Structure

• Bacteria are divided into two groups based upon
  the composition of their cell walls.
• Gram positive two layers ( lipid, peptidoglycan
  sugar/amino acids network)
• Gram negative three layers, lipid,
  peptidoglycan, and lipopolysaccharide.

Gram
Gram -
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Antibiotics

• Bacteria have a cell wall which gives protection.
  The cell walls of bacteria are made of long
  sugar chains linked with short amino acid chains.
• Most bacteria live in a hypotonic environment.
  (This means theres usually more water outside
  the cell than inside the cell)

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Antibiotics

• Most antibiotics aim to break down part of the
  cell wall to cause water to move in and rupture
  the bacteria cell.
• Penicillin is one bacteria to work this way.

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Journal Activity 3

• Using the internet or textbooks answer the
  following
• 1) Describe the discovery of the first
  antibiotic penicillin.
• 2) Describe one other antibiotic and explain how
  it works to kill bacteria cells.

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Bacteria/Uses

• Bacteria can be helpful or harmful to humans.
  Bacteria play many different roles in their
  environment.
• A few ways humans use bacteria is in the
  production of yogurt, swiss cheese and pickles.

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Bacteria

• One major role of bacteria in the envrironment is
  to fix nitrogen from the atmosphere into a
  useable form for plants.
• Several species of bacteria living in the soil
  have the ability to take diatomic nitrogen (N2)
  and convert it into ammonia (NH3). Other
  bacteria convert this ammonia into nitrite (NO2)
  and nitrate (NO3)

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Nitrogen Fixation

• Some nitrogen fixing bacteria form symbiotic
  relationships with legumes. ( beans, peas,
  soybeans, peanuts, etc.)
• These bacteria live on the roots of the plants
  and add nitrate and nitrite (useable forms of
  nitrogen for plants) into the soil.
• These crops are sometimes grown in off years to
  enrich the soil with useable nitrogen

Rhizobium bacteria live on legume roots.
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Bacteria - Decomposers

• Bacteria break down organic matter in dead
  organisms.
• These heterotrophic bacteria help recycle
  nutrients from dead plants and animals back into
  the soil.

Bacteria help break down leaves into useable
compounds in the soil.
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Bacteria

• Bacteria are very metabolically diverse.
• Different bacteria produce different waste
  products during fermentation. (Making ATP without
  oxygen)
• These waste products are used to make different
  food products (yogurt/pickles/swiss cheese/
  sauerkraut/ vinegar, etc)

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Bacteria

• Bacteria also are used to make antibiotics. Some
  helpful bacteria will produce chemicals which
  will kill pathogenic bacteria.
• Streptomycin and erythromycin are a few examples
  of antibiotics made from bacteria.

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Journal Activity 4

• Use the internet and other sources to answer the
  following
• 1) Pick one food which bacteria is used to
  produce and explain what bacteria does for the
  process.
• 2) Wastewater (sewage) plants use bacteria
  extensively. Research and describe how bacteria
  is used wastewater plants.

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Harmful Bacteria

• Most bacteria are not harmful, but a few cause
  disease in animals and plants.
• Its estimated that about half of all human
  diseases are caused by bacteria.

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Bacteria Caused Diseases

• Bacteria can cause the following diseases
• Tuberculosis
• Pneumonia
• Strep throat
• Staph infections
• Scarlet fever
• Syphilis
• Gonorrhea
• Chlamydia
• Boils
• Tetanus
• Lyme disease
• Ear infections

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Bacteria and Disease

• Bubonic Plague/Black Death.
• In the 1330s the bubonic plague originated in
  China. This disease caused by bacteria spread
  quickly to England and other parts of present day
  Europe.
• This bacteria was mainly found on rodents but
  fleas are thought to have carried it to humans.

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Bubonic Plague

• The bubonic plague killed an estimated 1/3rd of
  all Europeans.
• The bacteria caused boils which started as red
  bumbs on the skin, and then turned into black
  dots. Black Death.
• The bacteria Yersinia pestis is thought to have
  caused this disease.

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Pneumonia

• Pneumonia is a disease which can be caused by a
  virus or bacteria.
• Pneumonia involves a build-up of the pathogen in
  the lungs or respiratory system.
• The most common pneumonia is caused by the
  bacteria Streptococcus pneumonia. This bacteria
  grows in the lungs, causing the disease.

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Other Bacterial Diseases

• Many sexually transmitted diseases (STDs) are
  caused by bacteria.
• Gonorrhea
• Syphilus
• Chlamydia