Name __________________________________
Period __________
Bacteria and Viruses Outline
Bacteria
 Bacteria are __________________, ________________ (one-celled)
organisms that lack a _______________ membrane.
 Bacteria can live on land, in water, and in the air.
– They also live in and on both _______________ and
____________ plants and animals
 Most bacteria are _____________________.
– _____________ are organisms that _______ make their own food.
Shapes of Bacteria



Structure of Bacteria
A bacterium is made up of a
______________________
that encloses and protects
________________________.

Bacterial Nutrition
 Some bacteria live separately and others remain together to form
_________________.
– Colonies are __________________ of bacteria.
 There are bacteria that live as _________________.
– A parasite absorbs ____________________ from other living
organisms called their _______________.
 Others digest and absorb food materials from ____________ organisms.
– These bacteria are called ______________________.
Beneficial Bacteria
 Most bacteria are _______________ (_______________) to humans.
 Bacteria are __________________ that cause decay.
– Decomposers are organisms that _____________________ dead
organisms and ______________________ to the soil.
 Many bacteria are used to produce ________ and life-saving ________.
– Bacteria are used to make cheese, pickles, yogurt, vinegar, and
sauerkraut.
 By using methods of _______________________, bacteria have been
encouraged to ________________ substances such as insulin.
 The human intestinal tract contains millions of _______________.
– Many of these bacteria help the ______________ process and
others produce __________________.
 Bacteria are also used in the _______________ of leather, the ________
of tobacco, and the _____________________ of food for feeding cows.
Harmful Bacteria
Some bacteria are ________ beneficial to man.
Bacteria spoil food by secreting _______ into the food causing it to rot.
Along with enzymes, other substances produced by bacteria are
released into the food.
Some of these substances are ____________, making the food
__________________ to humans and other organisms.
Bacteria in large numbers can ____________ (dirty) lakes, streams,
and drinking water.
During ________________, bacteria reduce the dissolved oxygen
content in water supplies.
Many bacteria are ______________________.
A pathogen is an
Some bacterial ________________ of humans are tuberculosis,
tetanus, and strep throat.

Controlling Harmful Bacteria
 ________________, _______________, and ________________ are
used to control pathogenic bacteria.
– An antibiotic is a _______________ that can __________ the
growth of some bacteria.
– Bacteria are able to produce types that are ______________ to
certain antibiotics.
– When this happens, __________ antibiotics must be developed.
 Bacteria can also be ____________in foods by
– pasteurization,
– canning,
– chemical preservatives,
– radiation,
– steam/pressure,
– salt curing,
– dehydration (drying).
Harmful Anaerobic Bacteria
Some bacteria can live ____________________ and cause botulism.
A dangerous type of _____________________, in foods that
have not been properly canned.
Two other anaerobic bacteria can cause _________________ diseases
Gonorrhea (causes sterility)
Syphilis (can result in death).
A venereal disease is a contagious disease that a person gets through
_______________________.
Both diseases can be _______________ successfully by ____________
if detected early enough.

Viruses
 A virus is not a ________________.
 It is made up of ________________ material inside a ___________coat.
 Viruses do not carry on most __________________ activities.
 They can only _____________ inside a living cell called the _____ cell.
 Outside the host cell, a virus is “________” and often exists as a crystal.
 A virus has no means of _______________________.
Virus
Diagram
Negative Virus Influences
 They cause __________________ in both plants and animals.
 Some viruses cause ______________ and _____________.
 They also _______ cells and are responsible for human diseases such as
– polio,
– measles,
– mumps,
– influenza,
– hepatitis,
– colds,
– AIDS.
Influenza virus - Flu
Papilloma virus - Warts
Rabies Virus
Human Immunodeficiency Virus
AIDS
Positive Virus Influences
Certain viruses are used in the ________________ of insect pests.
Others are used in ______________________.
Scientists have been able to use viruses to biologically
__________________ caterpillars of the European pine sawfly and the
gypsy moth.

Bacteria and Viruses Outline – Teacher Guide (Key)
© Lisa Michalek
Bacteria
 Bacteria are microscopic, unicellular (one-celled) organisms that lack a nuclear
membrane
 Bacteria can live on land, in water, and in the air
– They also live in and on both living and dead plants and animals
 Most bacteria are heterotrophs.
– Heterotrophs are organisms that cannot make their own food
Shapes of Bacteria
 Coccus - round or sphere shaped
 Bacillus – rod shaped
 Spirillum – spiral shaped
Structure of Bacteria
 A bacterium is made up of a thick cell wall that encloses and protects cellular
material
Bacterial Nutrition
 Some bacteria live separately and others remain together to form colonies
– Colonies are large groups of bacteria
 There are bacteria that live as parasites
– A parasite absorbs food materials from other living organisms called their
hosts
 Others digest and absorb food materials from dead organisms
Beneficial Bacteria
 Most bacteria are beneficial (helpful) to humans
 Bacteria are decomposers that cause decay
– Decomposers are organisms that break down dead organisms and return the
nutrients to the soil
 Many bacteria are used to produce food and life-saving drugs
– Bacteria are used to make cheese, pickles, yogurt, vinegar, and sauerkraut
 By using methods of gene transplanting, bacteria have been encouraged to produce
substances such as insulin
 The human intestinal tract contains millions of bacteria
– Many of these bacteria help the digestive process and others produce
vitamins
 Bacteria are also used in the tanning of leather, the curing of tobacco, and the
production of food for feeding cows
Harmful Bacteria
 Some bacteria are not beneficial to man
 Bacteria spoil food by secreting enzymes into the food causing it to rot
– Along with enzymes, other substances produced by bacteria are released into
the food
– Some of these substances are toxic, making the food poisonous to humans
and other organisms
 Bacteria in large numbers can pollute (dirty) lakes, streams, and drinking water
 During respiration, bacteria reduce the dissolved oxygen content in water supplies
 Many bacteria are pathogenic
– A pathogen is an organism that causes disease and/or infection
– Some bacterial diseases of humans are tuberculosis, tetanus, and strep throat
Controlling Harmful Bacteria
 Antiseptics, disinfectants, and antibiotics are used to control pathogenic bacteria
– An antibiotic is a chemical that can stop the growth of some bacteria
– Bacteria are able to produce types that are resistant to certain antibiotics
– When this happens, new antibiotics must be developed.
 Bacteria can also be killed in foods by
– pasteurization
– canning
– chemical preservatives
– radiation
– steam/pressure
– salt curing
– dehydration (drying)
Harmful Anaerobic Bacteria
 Some bacteria can live anaerobically and cause botulism
– A dangerous type of food poisoning, in foods that have not been properly
canned
 Two other anaerobic bacteria can cause venereal diseases
– Gonorrhea (causes sterility)
– Syphilis (can result in death)
 A venereal disease is a contagious disease that a person gets through sexual
contact
 Both diseases can be treated successfully by antibiotics if detected early enough
Viruses
 A virus is not a cell
 It is made up of genetic material inside a protein coat
 Viruses do not carry on most metabolic activities
 They can only reproduce inside a living cell called the host cell
 Outside the host cell, a virus is “lifeless” and often exists as a crystal
 A virus has no means of locomotion
Negative Virus Influences
 They cause infections in both plants and animals
 Some viruses cause tumors and warts
 They also destroy cells and are responsible for human diseases such as
– polio
– measles
– mumps
– influenza
– hepatitis
– colds
– AIDS
Positive Virus Influences
 Certain viruses are used in the control of insect pests
 Others are used in genetic research
 Scientists have been able to use viruses to biologically control caterpillars of the
European pine sawfly and the gypsy moth