18.2: Bacteria

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18.2 Bacteria
prokaryote, chemosynthesis, binary fission,
conjugation, obligate aerobe, obligate anaerobe,
endospore, toxin, nitrogen fixation
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Diversity of Prokaryotes

• Prokaryotes unicellular organism that do not
  have a nucleus or membrane-bond organelles
• There are two kingdoms of prokaryotes because of
  the many biochemical differences between the two.
• Archaebacteria
• Eubacteria

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Archaebacteria

• There are three types of archaebacteria that live
  mainly in extreme habitats where there is usually
  no free oxygen available.

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Archaebacteria

• Methane Producing Archaebacteria live in
  oxygen-free environments and produce methane gas
  and are found in marshes, lake sediment, and live
  in the digestive tracts of some mammals such as
  cows. They also are found at sewage disposal
  plants, where they breakdown sewage.

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Archaebacteria

• Salt-Loving Archaebacteria live only in waters
  with high concentrations of salt, such as in
  Utahs Great Salt Lake and the Middle Easts Dead
  Sea

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Archaebacteria

• Heat-and Acid-Loving Archaebacteria live in hot,
  acidic waters of sulfur springs. They are also
  anaerobic and can thrive in cracks deep in the
  ocean floor.

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Eubacteria The Heterotrophs

• Live almost everywhere and use organic molecules
  as their food source.
• Some are parasites, obtaining their nutrients
  from other living organisms
• Some are saprophytes organisms that feed on dead
  organisms or organic waste
• This is important in recycling nutrients through
  the environment

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Eubacteria The Photosynthetic Autotrophs

• Live in places with sunlight so they can use the
  light to make organic molecules that are their
  food.

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Eubacteria The Photosynthetic Autotrophs

• Example Cyanobacteria
• Contain the pigment chlorophyll that traps solar
  energy, which they can then use in
  photosynthesis.
• Most are blue green in color and some can be red
  or yellow.
• They are commonly found in ponds, streams and
  moist areas of land.

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Eubacteria The Chemosynthetic Autotrophs

• These also make organic molecules for food.
• Instead of using sunlight, they break down and
  release energy of inorganic compounds containing
  sulfur and nitrogen in a process called
  chemosynthesis
• These bacteria are important for plants because
  they convert atmospheric nitrogen into the
  nitrogen-containing compounds that plants need.

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Bacteria Structure

• Capsule Some bacteria have a sticky gelatinous
  capsule around the cell wall. A bacterium with a
  capsule is more likely to cause disease than a
  bacterium without.
• Cell Wall surrounds the plasma membrane and
  gives the cell its shape and prevents osmosis
  from bursting the cell.
• Chromosomes A single DNA molecule, arranged as a
  circular chromosomes and not enclosed in a
  nucleus, contains most of the bacteriums genes

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Bacteria Sturcture

• Flagellum long, whip-like protrusion that
  enables them to move (not all bacterium contain
  flagella)
• Plasmid A few genes are located in a small
  circular chromosome piece called a plasmid. A
  bacterium can have one or more plasmid.
• Pilus some bacteria have pili- extensions of
  their plasma membrane. A hair-like pilus helps a
  bacterium stick to a surface. It is also like a
  bridge through or on which two bacteria can
  exchange genetic information.

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Bacteria Sturture

• Plasma membrane surrounds the cell and regulates
  what enters and leaves the cell.
• Ribosomes site of protein synthesis

Capsule
Chromosome
Cell Wall
Flagellum
Plasma membrane
Plasmid
Pilus
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Journal Drawing

• Draw a Typical Bacterial Cell in your Journal
  (Figure 18.10 pg. 487)
• Label and Define the Structures

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Identifying Bacteria

• Scientists have developed ways of distinguishing
  bacteria.
• One way is how they react to gram stains, which
  distinguish between two types of bacteria.

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Identifying Bacteria

• Gram stains reveal structural differences in
  cells cell walls. These differences are important
  in understanding what type of antibiotic will
  work effectively against the bacteria.
• Gram positive appears purple when stained
• Gram negative appears pink when stained

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Identifying Bacteria

• Bacteria also have different shapes.
• Coccus spheres
• Bacillus rods
• Spirillum spirals

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Identifying Bacteria

• Bacteria can have different arrangements
• Diplo paired cells
• Staphylo arrangement of cells resembling grapes
• Strepto chains of cells

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Journal Drawing

• Draw an example of each shape and arrangement of
  bacteria in your journal
• Refer to figure 18.12 pg. 489

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Reproduction

• Binary fission is a form of asexual reproduction
  used by bacteria.
• First, genetic information (chromosomes) are
  copied.
• The cell grows larger and the chromosomes move to
  opposite ends of the cell

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Reproduction Binary Fission

• Then a partition forms between the two
  chromosomes and separates the cell into two
  cells.

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Reproduction Binary Fission

• Because each new cell has either the original or
  the copy of the original chromosome, the
  resulting cells are genetically identical.
• Under ideal conditions some bacteria can
  reproduce every 20 minutes, producing enormous
  numbers quickly, but due to lack of nutrients and
  predators they do not always reproduce so
  quickly.

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Reproduction Binary Fission
http//www.youtube.com/watch?vJ6akNYlkehYNR1
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Reproduction Conjugation

• Conjugation is a form of sexual reproduction used
  by some bacteria
• In conjugation, one bacterium transfers all or
  part of its chromosome to another cell through a
  bridge-like structure called a pilus that
  connects the two cells.

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Reproduction Conjugation

• This results in bacteria cells with a new genetic
  composition
• Then binary fission can occur, producing more
  cells with the same genetic makeup.

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Adaptations in Bacteria

• Obligate aerobes bacteria that require oxygen
  from respiration
• Mycobacterium tuberculosis, the organism that
  causes the lug disease tuberculosis.

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Adaptations in Bacteria

• Obligate anaerobes killed in the presences of
  oxygen
• Treponema pallidum, causes syphilis, a sexually
  transmitted disease and the bacterium that causes
  botulism, a type of food poisoning.
• Some bacteria can live in the presence of oxygen
  or without oxygen.

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Adaptations in Bacteria

• Endospores a tiny structure that contains a
  bacteriums DNA and a small amount to its
  cytoplasm, encased by a tough outer covering that
  resists drying out, extreme temperatures, and
  harsh chemicals.

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Bacteria Adaptations Endospores

• If a bacterium is killed the endospore will rest
  until the conditions are favorable and germinate
  into the bacterium and grow and reproduce.
• Some have germinated after thousands of years in
  a resting state.
• Although useful to the bacteria, they can cause
  problems for people because they are difficult to
  terminate.
• This is why foods and surgical instruments must
  be sterilized properly

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Bacteria Adaptations Endospores

• The bacterium Clostridum botulinum easily gets
  into foods being canned and the endospores can
  germinated because they are obligate anaerobes.
• This can eventually produce a powerful and deadly
  poison, called a toxin, as they grow.
• If food is eaten with this toxin it can cause
  botulism.

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Importance of Bacteria

• Nitrogen Fixing
• Most of the nitrogen in the world consists of
  nitrogen gas (N2), and it makes up 80 percent of
  the atmosphere.
• Few organisms can use this nitrogen directly from
  the air.
• Nitrogen fixation a process in which several
  species of bacteria have enzymes that convert N2
  into ammonia (NH3)
• Other bacteria convert ammonia into nitrite
  (NO2-), which plants can use.
• Some nitrogen fixing bacteria live symbiotically
  within the roots of trees and legumes (peas,
  peanuts, and soybeans).

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Importance of Bacteria

• Recycling of Nutrients
• Decomposing bacteria break down the organic
  materials in dead organisms and wastes, returning
  nutrients, both organic and inorganic material,
  to the environment.

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Importance of Bacteria

• Food and Medicine
• Many foods you eat- Swiss cheese, , pickles,
  yogurt- would not exist without bacteria.
• During respiration, different bacteria produce
  diverse products, many of which have distinctive
  flavors and aromas. So they are used in many
  foods for these flavors (vinegar, cheeses,
  sauerkraut)

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Importance of Bacteria Food and Meds

• Bacteria also live in your intestines and produce
  vitamins and enzymes that help digest food
• Some bacteria produce important antibiotics that
  destroy other types of bacteria.

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Bacteria Cause Diseases

• Bacteria can cause diseases in plants and
  animals, causing crops and livestock losses that
  impact humans indirectly.
• Disease causing bacteria usually enter humans
  bodies through openings, such as you mouth or an
  open wound.
• The growth of the bacteria can interfere with
  normal function of body tissues, or it can
  release a toxin that directly attacks the host.

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Bacteria Cause Diseases

• In the past bacterial illness had a greater
  affect on the human population.
• In 1900 the life expectancy in the US was only
  47, because the most dangerous disease at that
  time was cause by bacteria (tuberculosis and
  pneumonia).
• The human life expectancy has increased to about
  75 years, due to better public health systems,
  improved water and swage treatment, better
  nutrition and better medical care (including
  antibiotics)

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Diseases Caused By Bacteria

• Strep throat inhale or ingest through mouth
  caused by Streptococcus.
• Tuberculosis inhale
• Tetanus puncture wound
• Lyme disease bite of infected tick
• Dental cavities bacteria in mouth
• Diphtheria inhale or close contact

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Diseases Caused By Bacteria

• Treatment can include cleaning, antibiotics or
  vaccinations.

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Bacteria You Need to Know

• Cyanobacteria
• Mycobacterium tuberculosis
• Treponema pallidum
• Streptococcus
• Clostridum botulinum
• Know diseases bacteria cause as well.

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Review

• Archaebacteria 3 types, where they are found
• Eubacteria Heterotrophs, Photosynthetic,
  Chemosynthetic
• Structure Be able to label and describe the
  functions
• Identification gram stain, shape, arrangement
• Adaptations anerobic, aerobic, endospores
• Importance Nitrogen Fixing, Food and Medicine,
  Recycling Nutrients
• Bacteria that cause disease How, examples,
  prevention