CHAPTER 7“BACTERIA” (P. 186)

• 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.

Two Kingdoms of Bacteria

1) Eubacteria

Phylum Bacteria

Phylum Cyanobacteria

- can make their own food.

2) Archebacteria

- oldest.

- live in extreme conditions. (page 191)

Bacteria was discovered by van Leeuwenhoek in 1684.

There are three shapes of bacteria (p. 187)

1) cocci- round

2) bacilli

-rod shaped

3) spirilla

- spiral shaped

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)

They can also reproduce sexually

• called conjugation.- an exchange of

genetic materials.

Bacteria coloniesBacteria colonies

Bacteria Structure

No nucleus.

Flagella for movement.

- the outermost layer is the capsule.- for protection.

- some create an endospore (or wall).- it protects against high

temperatures.

Draw and label the structures of bacteria

Bacteria decays our food.

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

To prevent decay:

2) High temperatures

- cook / boil / bake

- kills bacteria

3) Cold temperatures- freeze / refrigeration.- stops or slows bacteria growth.

4) Canning

- boiling

- then air-tight covering

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

6)Pasteurization

- heating to 1500 then quick cooled to 450.

- stored at low temps.

Ex. milk / apple juice

7) Seal it- bacteria cannot get in.

Bacteria are very “tough”.

Can live in:- hot springs

3500 F- ice- ocean depths- in your intestines- without oxygen

- anaerobic

ASSIGNMENT:BOOK QUESTIONS

PAGE 191: 1 / 2 / 4

PAGE 199: 3 / 4

Some Bacteria can cause disease:

ex. pneumonia / anthraxPathogen

- any organism which causes disease.

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

Antibiotics (against life)

- used to kill or slow the growth of bacteria.

Ex. penicillin amoxocillin

What is antibiotic resistance?

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.

There are different pigments which give cyanobacteria their color.

They are a source of food for other organisms.

They are the cause of the ‘green slime’ on the surface of ponds.

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’

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…

ASSIGNMENT:

WORKSHEET“BACTERIA”

HELPFUL BACTERIAHELPFUL BACTERIA1) Keeps the

environment free of dead material.

- decays plants and animals.

-breaks down our sewage and garbage.

-returns nutrients to the soil.

Saprophyte

- any organism which uses dead material for food.

2) Found in our intestines.

- helps break down our food.

3)3) Nitrogen fixersNitrogen fixers

- put nutrients back - put nutrients back into the soil.into the soil.

4) Economically important.

- cheese, butter, and yogurt are made from milk ‘soured’ by bacteria.

- different bacteria make a different type of cheese.

Harmful Bacteria1) Can cause fatal

diseases.

ex. Pneumonia, anthrax.

2) Can spoil food

- could lead to starvation.

ASSIGNMENT:WORKSHEET

‘BACTERIA IN YOUR LIFE’

VIRUSES ( p. 52 - 55 )

• are not cells- there is not a nucleus, cytoplasm, etc.

• spread disease.• very small -

microscopic.• many different

shapes. (p. 52)

Viruses are not considered to be alive.

- are not in any kingdom.

- cannot respond to stimuli.

- can reproduce only inside a living cell.

A VIRUS IS MADE UP OF TWO PARTS:

1)Protein coat - the outside.- for protection

2)Nucleic Acid- genetic

material.

cccc

HOW DO THEY CAUSE HOW DO THEY CAUSE DISEASE?DISEASE?

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

2) Invade

- the virus injects its nucleic acid into the host cell

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.

Chicken pox, AIDS, the common cold, measles, and small pox are all caused by viruses.- spread by water, touch, air, and insects.

ASSIGNMENT:WORKSHEET

“VIRUS ATTACK”

Latent viruses - may “hide” in the host cell for years before “taking over”.

ex. cold sore

AIDS

Active viruses enter and take over a cell immediately.

VACCINES• made of a weakened

or damaged virus that cannot cause the disease.

• cannot cure viral diseases

- it prevents them from happening.

First created by First created by Edward JennerEdward Jenner in 1796 in 1796 to fight smallpoxto 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

- 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.

Vaccinations have almost eradicated many diseases.

Example: Polio- attacks the nervous system.

President Franklin Roosevelt (FDR)

Example II:

Smallpox

- thought to be eradicated in 1981.

The body does have natural defenses against viruses.

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

Vaccines can prevent Vaccines can prevent epidemicsepidemics.- the rapid spread

of a disease through an area.Ex. influenza (1917 - 1919)

-killed 10 million world wide.

“Black Death” or Bubonic Plague.- 1300’s in Europe.

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.

ASSIGNMENT:

WORKSHEET“VIRUSES”

Viruses may someday help :

Ex. Gene therapy- a gene is ‘defective’ and has 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.

ASSIGNMENT:Using Vocab.P. 204 1 - 6

Checking ConceptsP. 204 8 - 15