Chapter 7!Viruses, Bacteria, Protists, &

Fungi!p. 208

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Vocabulary• virus!• bacteria!• protist!• fungi!• vaccine!• pasteurization!• protozoan!!

• parasite!• host!• pseudopod!• flagellum!• cilia!• decomposer

Virus - a non-living particle that invades

and multiples inside a living cell

Viruses

Is a virus alive? !!

Is it an organism?

A Flu Virus

• non-living!• multiply differently

than organisms!• multiplies inside host!• act like parasites

Characteristics of Viruses

Host - organism on which a virus lives!

!

Parasite - organism that lives on host

and causes it harm

• smaller than cells!• vary in size and shape: rods,

bricks, threads, etc.!• protein coat: protects virus!• inner core made of genetic

material: contains instructions for making new viruses!

• envelope: outer membrane on some viruses

Structure of Viruses

Rod-shaped viruses

Structure of VirusesEach virus contains unique surface proteins. The shape of the surface proteins allows to the virus to attach to certain cells in the host. This “lock and key” action is specific to each virus.

1. Virus attaches to cell!2. Virus enters cell!3. Virus’s genetic material takes

over cell functions!4. Instructs cell to produce

virus’s surface proteins and genetic material!

5. Proteins and genetic material assemble into new viruses

How Viruses Multiply

Active Viruses - !go into action immediately!

Ex. Flu,Colds

A !Common

Cold !Virus

Hidden Viruses - !Genetic material becomes part of cell’s genetic material, but does not appear to affect cell

functions; may stay inactive for years until conditions are just

right to become active!!

Ex. Cold sores!Shingles

Viruses can affect people, plants, and

animals.

A Plant Virus

There are no cures for viral diseases.

How to Treat Viral Diseases!1. Rest!2. Drink fluids!3. Eat wellWhy do you think

each of these helps treat the virus?

Vaccine - substance introduced into the

body to destroy specific disease causing viruses

Preventing Viruses

M-M-R Vaccine

What Diseases Does M - M - R help prevent?

1. Flu!2. Polio!3. Chicken pox!4. Measles

Vaccines

What are these diseases? !Use iPads to learn about them.

Bacteria - !single celled

organisms without a nucleus

Bacteria

Microscopic view of bacteria

Are bacteria alive? !

How do you know?

Hint: Characteristics of

Life…!Do you remember?

Are Bacteria…!1. Made of Cells?!2. Composed of Chemicals?!

!

Do Bacteria…!4. Need Food & Energy?!5. Reproduce?!6. Grow & and Develop?!7. Respond to their Environment?!8. Release Waste?

• Autotrophs or heterotrophs!Who remembers? !Autotrophs vs. heterotroph…!• Conduct respiration and

break down food for energy

Bacteria Need !Food and Energy

Structure of Bacteria

• No nucleus!• Vary in size: largest

about as big as a period at the end of a sentence; some only one millionth of a meter

Bacteria magnified on the

head of a pin

• Shapes: spheres, rods, spirals!

• May have a flagellum

Structure of Bacteria

Flagellum - !whip-like structure that

helps a cell move

Structure of Bacteria

Role of Bacteria1. Produce Oxygen!2. Produce Foods!3. Decomposers!4. Environmental Recycling &

Cleanup!5. Health & Medicine

Not all Bacteria are Bad!

As Autotrophic Bacteria use the sun’s

energy to produce their food, they release

oxygen into the air

Autotrophic bacteria releases oxygen

Cyanobacteria in water is

autotrophic

As Bacteria grow in certain substances they produce foods such as…!• cheese!• pickles!• yogurt!• sour cream

Some bacteria cause food to spoil when they break

down the foods’s chemicals. Spoiled food

usually smells & tastes foul and can make you sick. !To prevent this you can

refrigerate or heat the food.

Pasteurization - heating food to kill bacteria

Louis Pasteur!French scientist!

(1822 - 1895)!Also developed

vaccines for anthrax and

rabies

What do you probably drink every day that is

pasteurized?

And the Answer is…

Hetereotrophic Bacteria in the soil are decomposers -

organisms that break down dead organisms !

They are nature’s “recyclers”.!!

Some bacteria can clean oil or chemicals and help with

environmental cleanup.

Oil-eating bacteria can help clean oil

spills.

Did you know many bacteria living in your body keep you

healthy?!!

• Bacteria in intestines help digest food!

• Bacteria compete for space with harmful bacteria!

• Bacteria is used to produce human insulin which helps those with diabetes

Protists

Protist - !one celled organism

with a nucleus

Protists

1. Animal - like!2. Plant -like

Protozoan - animal-like protist!

• With pseudopods!• With cilia!• With flagella!• Parasites

Animal-Like Protists

Pseudopod - !temporary bulge or

“false foot”, for movement!

!

Amoeba with Pseudopods

Amoeba Feeding

Cilia - !tiny hairs used for

movement

Paramecium with Cilia

Flagellum - !whip-like structure used for movement

Euglena with Flagellum

Who remembers -What is a parasite?

Flea

Tick

Plant-Like Protists

• Diatoms!• Dinoflagellates!• Euglenoids!• Algae

When diatoms die, they slowly sink to the seabed. The buildup of trillions of these shells forms a

crumbly white sediment which is used in manufacturing pool filters and abrasives, !

including toothpaste.

Fungus-Like Protists• Slime Molds!• Water Molds!• Mildews

Slime Mold

Bread Mold

Mildew on Leaf

Fungi - !multi celled organisms

Characteristics of Fungi!• Eukaryotes!• Cell Walls!• Heterotrophs!• Feed by absorbing

Food!• Use spores to

reproduce

Mushrooms

Fungi on Tree

Role of Fungi!• Food!• Decomposers!• Fight diseases!• Cause some plant

diseases!• Help some plant roots!• Lichens

Alexander Fleming!Scotland!

1881 - 1955

Nobel Prize 1945

Lichen = fungus + algae or autotrophic bacteria living in mutualism;!

Pioneer species

Lichens on tree!!

Mutualism!!

Fungus gets food produced by the algae or bacteria. Algae or bacteria get shelter, water,

and minerals from the fungus.