Bacteria and Viruses

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					Bacteria and Viruses
       Chapter 6
       Classifying Organisms
Take out your lab book.
    Answer the question below.
How do libraries organize their books?
First are they fiction             Next, by subject
or non-fiction                     matter.

Then, alphabetically by author’s
last name, first name.           Finally, by title.
       Classifying Organisms
Why do scientists classify?

                 This includes bacteria, plants and

There are at least 2.5 million kinds of organisms on

  How else are you going to keep them organized?
     Classifying Organisms
Classification: the process of grouping
things based on their similarities.

    Biologists use classification to organize
    living things into groups so that organisms
    are easier to study.
       Classifying Organisms
Early Classification Systems
   Aristotle (Greek scholar)
Recorded animals appearance, behavior, and
              Divided them into groups.

 Those that                    Those that swim.
         That that walk, crawl or run
     Classifying Organisms
Aristotle’s method is the basis of that
which is used today.
     Classifying Organisms
The classification system of Linnaeus
 Carl von Linne is his
 “real” name.

Expanding on
Aristotle’s ideas of
classification Linnaeus
devised a naming
system for organisms.
         Classifying Organisms
Binomial nomenclature: a two-part naming
system for each organism.
    Names are taken from the Latin language.

                 House cat

     Classifying Organisms
Genus: a classification grouping that
contains similar, closely related
                 The genus Felis includes pumas,
                 ocelots, and house cats.

                       Felis shares the features
                       of sharp, retractable
                       claws and hunting
     Classifying Organisms
Species: a group of similar organisms that
can mate and produce fertile offspring in

     The species name often describes a
     distinctive feature of the organism, such as
     where it lives or its color.
          Classifying Organisms
                                 Genus: Felis
                                 Species: domesticus

                     House cat

Genus: Felis
Species: paradalis
       Classifying Organisms
Levels of classification
   Based upon both Aristotle’s and Linnaeus’s

    There are seven levels of classification.
   Classifying Organisms
                      Invent a
Kingdom   Kind        memory
Phylum    Pavalko     device to help
                      you remember
Class     Cooks       the order.
Order     Our         You will need
          Family      to have the
Family                order
Genus     Good        memorized for
          Spaghetti   the quiz.
           Science news
December 7, 2007
A new giant species of spitting cobra --
about 2.6 meters long and with enough
venom to kill up to 20 people in one bite --
has been discovered in Kenya.
          Science News
The large brown spitting cobra, initially
included under the black-necked
spitting cobra species, was discovered
at a snake farm in June 2004, but
confirmed as a separate species this
       More Science News
A new type of
creature with a
snout similar to an
elephant's trunk
has been found in
the mountains of
Tanzania, the first
new species of the
mammal found
since the 19th
century, scientists
Section 3
           The Bacteria Cell
Bacteria are single-celled organisms.
Traits of bacteria
   Prokaryotes: cell does not contain a nucleus.
   Unicellular: single-celled
   Autotrophic or heterotrophic
           The Bacteria Cell
Shapes (page 193 in text)
Bacteria takes three shapes
   Spherical
   Rodlike
   Spiral
The shape helps with identification.
   Strep throat is spherical.
           The Bacteria Cell
   The cell shape is determine by the chemical
    makeup of its outermost structure.
   Most bacteria have a cell wall.
   A cell wall is a rigid structure protecting the
           The Bacteria Cell
Other structures in the bacteria cell
   Cell membrane
      Which controls what gets into and out of the cell.
   Cytoplasm
      Gel-like material covering the inside of the cell.
   Ribosomes
      Where proteins are produced.
   Genetic material
      Thick, tangled string-like material. This tells the
      bacteria its mission in life.
           The Bacteria Cell
Other structures in the bacteria cell
   Flagellum
      Long, whiplike structure that extends from the cell
      membrane and passes out through the cell wall.
      This helps the cell to move.
      Bacteria without flagellum cannot move on its own.
     Two Bacteria Kingdoms
   Live in extreme environments
       Hot springs
       Acidic lemon juice
       Animal intestines
          It’s the bacteria that makes the stink you stay
           away from!
      Two Bacteria Kingdoms
   They live everywhere, but extreme conditions.
      Right now there are about a bazillion of them
      crawling all over you skin!
      Never fear they are harmless.
      These are generally your helpful bacteria.
      High Five!
   Reproduction in Bacteria
Under ideal conditions bacteria can
reproduce every 20 minutes.
This rarely happens.
Otherwise, they would take up all the
space in the world!
     Reproduction in Bacteria
Binary Fission
   A process where bacteria reproduce by
    dividing to form two identical cells.
   Involves one parent.
   Produces a copy of the parent.
Asexual Reproduction
   Reproduction that involves only one parent
    and produces a clone.
     Reproduction in Bacteria
Sexual Reproduction (page 196)
   Involves two parents who combine their
    genetic material to produce a new offspring.
   Also called conjugation
      During conjugation genetic material is transferred
      from one bacterium to another through a threadlike
      This results in a bacteria with new combinations of
      genetic material.
              Survival Needs
Obtaining food
   Autotrophs: make their own food
      Some capture and use sunlight energy.
      Others use energy from chemicals
      substances in their environment.
          These live in the deep oceans.
             Survival needs
Obtaining food
   Heterotrophs
   Consume autotrophs or other heterotrophs.
   Consume other types of food.
      Decaying leaves
             Survival Needs
   A constant supply of energy is needed to
    carry out their functions.
      Comes from food.
   Breaking down the food to release its energy
    is called respiration.
      Requires oxygen for most bacteria.
      But not all…to some bacteria oxygen is death.
             Survival Needs
Endospore Formation
   An endospore is a
    small, rounded, thick-
    walled, resting cell
    that forms inside a
    bacteria cell.
      Contains the bacteria’s
      genetic material and
      some of its cytoplasm.
            Survival Needs
Endospore Formation
   When conditions become suitable for the
    bacteria to thrive the endospore opens.
   The bacteria resume its life.
   However, it may take years for this to happen.
Bacteria and the Living World
   Most bacteria are harmless or positive.
      Help age cheese.
      Help keep soil fertile.
   Some bacteria are harmful.
      Strep throat.
      Ear infections.
      Girl or boy cooties.
Bacteria and the Living World
Bacteria are involved in fuel and food
production as well as in environmental
recycling and cleanup.
However, some bacteria do cause
diseases and other harmful effects.
Bacteria and the Living World
   Archaebacteria produce methane.
       Used in cooking.
   Bacteria help make these foods.
       Apple cider
Bacteria and the Living World
   Bacteria also causes food to spoil.
Environmental Recycling
   Decomposers: organisms that break down
    large chemicals in dead organisms into small
      Nature’s recyclers.
   Some heterotrophic eubacteria are examples.
Bacteria and the Living World
Illness and health.
   Infectious disease: illnesses that pass from
    one organism to another.
   Bacteria cause strep throat or food poisoning
    which are examples.
Bacteria and the Living World
Spreading infectious diseases
   Inhaling drops of sneeze.
   Touching
   Hugging
   KISSING…aaaaaahhhhhhh!!!!
   Some are found naturally in the environment.
Bacteria and the Living World
Toxin: a poison.
   Produced by bacteria causing illness.
Antibiotic: a chemical that can kill bacteria
without harming a person’s own cells.
   Penicillin is an example.
    Bird Flu

Section 4
            Lab Books
Name any disease with which you are
familiar, in your lab book.
          What is a virus?
A small, nonliving particle that invades and
then reproduces inside a living cell.

 Biologists consider
 viruses to be nonliving
 because they are not
Viruses do not use energy to
grow or to respond to their
         What is a virus?
Viruses also cannot make food, take in
food, or produce waste.
Their only similarity to organisms is the
ability to reproduce.
         What is a virus?
A host is a living thing that provides a
source of energy for a virus, or organism.
Organisms that live on or in a host and
cause harm to the host are called
Almost all viruses act as parasites.
            Naming Viruses
Because they are not alive scientists do
not use binomial nomenclature to name
   The Ebola virus was named after the place in
    Africa where it was first found.
   Epstein-Barr virus was named for the
    scientists who first identified it.
   Polio virus is named for the disease it causes.
           Shape and Size
Viruses vary widely in shape. (page 206)
   Round
   Bricklike
   Threadlike
   Robotlike
   Bulletlike

      HIV virus 
         Shape and Size
Some even look a little robotic.
A bacteriophage is a virus that infects

 Name means,
 “bacteria eater.”
        Shape and Size
Viruses are smaller than cells.
They are measured in nanometers (nm).
 1 foot = 12 inches = 304,800,000 nm
         Structure of Viruses
Parts of a Virus
   Outer coat which protects the virus.
      Made of proteins
      Used to lock onto cells
   Inner core made of genetic material.
        How Viruses Multiply
First, the virus attaches to the cell.
Next, it enters the cell.
   Once inside the cell, a virus’s genetic material
    takes over the cell’s functions.
       How Viruses Multiply
   The genetic material directs the cell to
    produce the virus’s proteins and genetic
   These proteins and genetic material are
    then assembled into new viruses.
        How Viruses Multiply
Active Viruses
   They immediately take over a cells functions.
   The cell quickly begins to produce the virus’s
    proteins and genetic materials.
        How Viruses Multiply
Hidden Viruses
   Genetic material enters the host’s cell.
   Instead of going into action, the virus’s
    genetic material becomes part of the cell’s
    genetic material.
   Does not seem to infect the host.
   Then, one day, it suddenly becomes active.
        How Viruses Multiply
Hidden Viruses
   Why the wait?
   Scientists are perplexed.
Examples of hidden viruses
   Cold sore virus
      Hides in the nerve cells.
      Becomes active
      Why? Stress and strong sunlight are possible
           Viral Diseases
No medications can cure viral infections.
Many medicines treat the symptoms.
Best treatment
   Bed rest.
   Drink lots of fluids.
   Eat healthy.
A vaccine is a substance that stimulates
the body to produce chemicals that
destroy viruses or bacteria.
   May be made from dead or altered viruses or
   This dead virus or bacteria does not cause
    the illness, but instead activates the body’s
    natural defenses.
Turn in your text to page 201.
Turn in your text to page 210.

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