CHAPTER SEVEN

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CHAPTER SEVENBACTERIA VIRUSES p. 160
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CHAPTER SEVEN I CANS BACTERIA AND VIRUSES 1. I
can explain the different ways to protect our
food from bacteria. 2. I can discuss the
reasons why bacteria are helpful and
harmful. 3. I can list examples of bacterial
diseases and how they can be treated.   4. I
can identify the steps of virus reproduction. 5.
I can explain how vaccinations prevent
disease.    
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• are unicellular.
• are prokaryotic.
• - their DNA floats around in the cytoplasm.
• creates foods.
• - cheeses/yogurt.
• some cause disease.
• ex. strep throat / anthrax
• have cell walls.
• live everywhere.
• in cold, hot, air, soil, etc.

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Two Kingdoms of Bacteria

• Eubacteria
• Phylum Bacteria
• Phylum Cyanobacteria
• - can make their own food.

• Archebacteria
• - oldest.
• - live in extreme conditions. (page 191)

Bacteria was discovered by van Leeuwenhoek in
1684.
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There are three shapes of bacteria (p. 187)

• cocci
• - round

• bacilli
• -rod shaped

• spirilla
• - spiral shaped

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• Some live by themselves, in chains, or in groups
  called colonies.

Bacteria can reproduce asexually by quickly
splitting into two cells. - called fission.
(20 minutes)
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Bacteria colonies
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They can also reproduce sexually

• called conjugation.
• - an exchange of genetic materials.

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Bacteria Reproduction
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Bacteria Structure

• No nucleus.
• Flagella for movement.

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Draw and label the structures of bacteria

• the outermost layer is the capsule.
• - for protection.
• some create an endospore (or wall).
• - it protects against high
• temperatures.

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Bacteria decays our food.
To prevent decay

• Dehydration
• - water is removed from food.
• -bacteria need water to survive.

2) High temperatures - cook / boil / bake -
kills bacteria
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• 3) Cold temperatures
• - freeze / refrigeration.
• - stops or slows bacteria growth.

• 4) Canning
• boiling
• - then air-tight covering

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• 5) irradiation
• - exposing food to radiation to kill bacteria.

• Pasteurization
• - heating to 1500 then quick cooled to 450.
• - stored at low temps.
• Ex. milk / apple juice

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• 7) Seal it
• - bacteria cannot get in.

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Bacteria are very tough.

• Can live in
• - hot springs
• 3500 F
• - ice
• - ocean depths
• - in your intestines
• - without oxygen
• - anaerobic

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ASSIGNMENTBOOK QUESTIONSPAGE 191 1 / 2 /
4PAGE 199 3 / 4
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Some Bacteria can cause disease ex. pneumonia /
anthrax

• Pathogen
• - any organism which causes disease.

Some bacteria destroy cells by releasing a
toxin. ex. botulism flesh-eating bacteria
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Antibiotics

• (against life)
• used to kill or slow the growth of bacteria.
• Ex. penicillin
• amoxocillin

What is antibiotic resistance?
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Cyanobacteria (p. 190)

• second phylum of Eubacteria.
• have chlorophyll but not chloroplasts.
• also called blue-green algae.
• many live in long chains.
• not all are blue-green there are red, yellow,
  and black.

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There are different pigments which give
cyanobacteria their color.

• They are a source of food for
• other organisms.

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They are the cause of the green slime on the
surface of ponds.
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Cyanobacteria are called nitrogen-fixers.

• they grow among the roots of certain plants.
• Ex. soybeans, alfalfa
• take nitrogen out of the air and create nodules
  in the soil.
• adds nutrients.
• saves on fertilizer.

Soybean nodules
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A lot of nutrients in the water causes rapid
growth called a bloom.

• the cyanobacteria die and sink to the bottom.
• other bacteria decompose them.
• it takes oxygen out of the water.
• the fish die

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ASSIGNMENTWORKSHEETBACTERIA
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HELPFUL BACTERIA

• Keeps the environment free of dead material.
• - decays plants and animals.
• -breaks down our sewage and garbage.
• -returns nutrients to the soil.

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• Saprophyte
• - any organism which uses dead material for
  food.
• 2) Found in our intestines.
• - helps break down our food.

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• Nitrogen fixers
• - put nutrients back into the soil.

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• Economically important.
• cheese, and yogurt are made from milk soured by
  bacteria.
• different bacteria make a different type of
  cheese.

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5) Can make medicines.

• Can make vaccines to prevent some bacterial
  diseases.
• Ex. tetanus

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Harmful Bacteria

• Can cause fatal diseases.
• ex. Pneumonia, anthrax.

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• 2) Can spoil food
• - could lead to starvation.

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ASSIGNMENTWORKSHEETBACTERIA IN YOUR LIFE
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VIRUSES ( p. 52 - 55 )

• are not cells
• - there is not a nucleus, cytoplasm, etc.
• spread disease.
• very small - microscopic.
• many different shapes. (p. 52)

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• Viruses are not considered to be alive.
• - are not in any kingdom.
• - cannot respond to stimuli.
• - can reproduce only inside a living cell.

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A VIRUS IS MADE UP OF TWO PARTS

• Protein coat
• - the outside.
• - for protection
• Nucleic Acid
• - genetic material.

cccc
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VIRUSES
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HOW DO THEY CAUSE DISEASE?

• Attach
• -the virus attaches itself to a host cell of an
  organism.

2) Invade - the virus injects its nucleic
acid into the host cell
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• 3) Copy
• - the virus nucleic acid takes-over the host
  cell.
• - it forces the cell to make copies of the virus
  instead of new cells.

4) Release - the cell finally bursts.
Hundreds of new viruses are released to attack
new cells.
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• Chicken pox, AIDS, the common cold, measles, and
  small pox are all caused by viruses.
• - spread by water, touch, air, and insects.

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ASSIGNMENTWORKSHEET VIRUS ATTACK
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Latent viruses

• may hide in the host cell for years before
  taking over.
• ex. cold sore
• HIV
• Active viruses enter and take over a cell
  immediately.
• ex. common cold

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VACCINES

• made of a weakened or damaged virus that cannot
  cause the disease.
• cannot cure viral diseases
• - it prevents them from happening.

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First created by Edward Jenner in 1796 to fight
smallpox.

• He noticed the milkmaids did not have the
  scars from smallpox.
• All had clear skin but did have cowpox before.
• He used the sores from cowpox

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- the body reacts and destroys the weak virus.

• -the body produces an antigen which remembers
  the virus and will destroy it when enters the
  body again.

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Vaccinations have almost eradicated many diseases.

• Example Polio
• - attacks the nervous system.
• President Franklin Roosevelt (FDR)

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• Example II
• Smallpox
• - thought to be eradicated in 1981.

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VACCINES
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The body does have natural defenses against
viruses.

• Interferon
• - a chemical which slows down the reproduction
  of viruses.
• - now used in cancer treatments.

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Vaccines can prevent epidemics.

• the rapid spread of a disease through an area.
• Ex. influenza (1917 - 1919)
• -killed 10 million world wide.

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• Black Death or Bubonic Plague.
• - 1300s in Europe.

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Viruses can change or mutate.

• there are thousands of types of the common cold.
• Scientists are now worried about bird flu
• mutating into a human disease.

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ASSIGNMENTWORKSHEETVIRUSES
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Viruses may someday help

• Ex. Gene therapy
• - a gene is defective. ex.sickle-cell anemia
• - a virus nucleic acid will be replaced with
  healthy DNA.
• - the virus attacks and replaces the bad DNA

May help people with genetic diseases.
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ASSIGNMENTUsing Vocab.P. 204 1 - 7Checking
ConceptsP. 204 9 - 15Skip 12
59
CHAPTER SEVEN I CANS BACTERIA AND VIRUSES 1. I
can explain the different ways to protect our
food from bacteria. 2. I can discuss the
reasons why bacteria are helpful and
harmful. 3. I can list examples of bacterial
diseases and how they can be treated.   4. I
can identify the steps of virus reproduction. 5.
I can explain how vaccinations prevent
disease.