Viruses, Bacteria, Protists, Fungi

Chapter 7Grade 7 Science

Viruses

• _____ - a tiny, non-living particle invades and then multiplies inside of a living cell.

• Viruses can only multiply when they are _____ of a living cell.

• ______ - a living thing that provides the energy source for a virus.

• ________ - organisms that live on or in a host and can cause it harm.

• Viruses act like parasites but they are not ___________.

Virus

inside

host

parasite

organisms

Structure of Viruses

• Viruses have three distinct shapes:– _________– _______– ________All viruses have two basic parts:1. A __________ that protects the virus2. A ___________ made of genetic material

round

rods

threads

Protein coatInner core

Virus Structure and Host Cells

• Viruses are like ______ that fit into ______ which is a protein on the surface of a host cell.

• ______________ - the shape of surface proteins allows the proteins to fit into a only certain proteins that are located on the surface of the host.

• ______________ - a virus that infects bacteria and has a robot-like shape.

keys locks

Lock and Key action

bacteriophage

How Viruses Multiply

• After a _________ attaches to a ________ it enters the cell.

• After the virus enters the cell, the ____________ takes over many of the cell’s functions.

• The ___________ instructs the cell to produce the virus’s proteins and genetic material.

• The ________ and ___________ continue to multiply into new viruses

virus Host cell

genetic material

genetic material

proteins genetic material

Active Viruses

• ___________ - enter cells and immediately begin to multiply leading to the quick death of the invaded cells.

• _____________ - “hide” for a while before becoming active inside of the host cell. The hidden virus hides inside of the host cells ___________ before it becomes active.

Active Viruses

Hidden Virus

Genetic material

Viruses and Diseases

• ________ cause ________• Viral diseases are spread through ________,

_________, _____________, and ___________.

• _________ - a substance introduced into the body to stimulate the production of chemicals that destroy specific disease causing viruses and organisms – a ___________ measure.

Viruses diseases

contact

bites Drops of moisture

Body fluids

Vaccine

preventative

Bacteria

• ________________ - discovered bacteria in the late 1600’s.

• __________ - single celled organisms with no nucleus.

• __________ - the genetic material is not contained in the nucleus.

• Bacteria cells have _______ and __________

Anton van Leeuwenhoek

bacteria

prokaryotes

Cell wall Cell membrane

Bacteria – Structure

Bacteria - Size

Obtaining Food and Energy

• Bacteria must have :1. _____________2. ______________Some Bacteria are __________ - self feedersBacteria make their food in 2 ways:3. ______________4. _______________________________________Some bacteria are __________ - other feeders that

feed on other organisms or the food that other organisms make.

Source of foodEnergy supply

autotrophs

Suns energyEnergy from chemical substances in the environment

heterotrophs

Respiration

• _________ comes from breaking down food in the process of __________.

• Some bacteria need ________ for respiration• Others do not need ________ - these bacteria

are called __________ and will die in the presence of oxygen.

energy

respiration

oxygen

oxygen

anaerobic

Reproduction

• Bacteria need the following for reproduction:1. ___________2. ___________3. _______________________________ - reproductive process that

requires only one parent.- ___________ - one cell divides to form two identical cells – each cell gets its own complete copy of the parents cell’s genetic material, ribosomes and cytoplasm

foodtemperatureSuitable conditions

Asexual Reproduction

Binary fission

Reproduction Continued

• ______________ - two parents combine their genetic material to produce a new organisms.– _________ - one bacterium transfers some genetic

material to another and then the cells separate.– Bacteria can survive harsh conditions by forming

__________ - a small, round, thick-walled, resting cell that forms inside a bacterial cell.- endospores can resist _________, _______, and______ - they can survive for many years

Sexual reproduction

conjugation

endospores

freezing heatingdrying

Bacteria in Nature

• Bacteria are involved in:– ______________________– ___________________________– _________________– _________________Scientists believe that _________________ were

responsible for adding oxygen to the Earth’s atmosphere.

Bacteria keep oxygen levels in the air ________.

Oxygen and food production

Environmental recycling and cleanupHealth maintenance

Medicine Production

Autotrophic bacteria

stable

Food Production / Environmental Recycling

• __________- named after Louis Pasteur, is a process where beverages such as milk and juices are heated to a temperature high enough to kill harmful bacteria without destroying the taste.

• ___________ - are “nature’s recyclers” – return basic chemicals such as ______ to the environment for other living things to use.

Pasteurization

Decomposers

nitrogen

Recycling and Nitrogen-Fixing

• ________________ break down chemicals in leaves and branches that drop to the ground. Once these materials are broken down, they mix with soil and can be absorbed from _______ of nearby plants.

• ________________ live in soils and convert nitrogen gas from the air to nitrogen products that plants need to grow.

Nitrogen-fixing bacteria

roots

Decomposing bacteria

Health and Medicine

• Bacteria _______________• Bacteria ____________• Good bacteria can help harmful bacteria from

making your sick.• ________________ - purified and made into

medicine for people that cannot make their own.

Help to digest food

Make vitamins

Insulin-making bacteria

Protists

• ___________ - eukaryotes that cannot be classifies as animals, plants, or fungi

• All protists live in _____ surroundings.• Animal-like protists - ________ are

__________ - other feeders.• Protozoans are __________ - one celled• Protozoans are classified into 4 groups based

on the way they ________ and ________

Protists

moist

heterotrophsprotozoans

unicellular

move live

Protozoans with Pseudopods

• ________ - sarcodines that live in either water or soil.

• __________ - move and feed by forming pseudopods.

• Pseudopod means “__________” – temporary bulges in the cell

• Pseuodopds move when the _______ flows in one direction and the rest of the organism follows

amoeba

Sarcodines

False foot

cytoplasm

Pseudopds

• Sarcodines use pseudopds to __________.• The pseudopds are extended on both sides of

the food particle until the pseudopods join together and the particle is trapped.

• _______________ - a structure that collects extra water that is taken into the cells of protozoans that live in fresh water such as _______ - the water is then expelled so that the amoeba will not burst.

Trap food

Contractile vacuole

amoeba

Protozoans with Cilia

• ____ - hair like projections from cells that move in a wavelike motion.

• _______ use cilia to _____ and obtain _____.• __________ - ciliates that are complex – two

_____________ and more than one _______• Paramecium reproduce __________ by

___________or ___________

cilia

ciliates move food

paramecium

Contractile vacuoles nucleus

asexually

Binary fission conjugation

Protozoans with Flagella

• Protists that use long, whip-like structures to move - _______

• Some _________ live inside of the bodies of other organisms.

• The relationship where one organism is helped is called ________. (ex. Flagellate that lives inside of the intestine of termites)

• The relationship where both organisms are benefited is called ________ - a type of _________

flagella

protozoans

symbiosis

mutualismsymbiosis

Protozoans that are Parasites

Plantlike Protists

• Plantlike protists are called _____.• Algea are __________.• Algea are _________ and / or ____________• _______ are groups of unicellular organisms

that live together – some cells in the colony are specialized for certain functions such as ____________

• Some algea are also __________

algae

autotrophs

Food sources Oxygen producers

colonies

multicellular

reproduction

Diatoms

________ are unicellular protists with glasslike cell walls.

Diatoms are a _________ for ___________organisms in waters – diatoms either float or attach to objects in shallow waters.

Diatoms move by oozing chemicals from their cell walls and then gliding in the slime.

Diatoms

Food source

heterotrophic

Dinoflagellates

• _____________ - unicellular algea surrounded by stiff plates

• Dinoflagellates have two _______ that are held in between their plates.

• Dinoflagellates whirl through the water with their flagella and some are ______________.

• Found on the surface of _______ waters

dinoflagellates

flagella

Glow in the dark

ocean

Euglenoids

• ________ are green unicellular algea that are found in fresh water.

• Euglenoids have one animal-like characteristic – they can be ___________ when sunlight is not available.

• ________- a common euglenoid that has a long whip-like flagellum that helps it to move..

• _______ - helps the euglena to find light sources – valuable for autotrophs.

Euglenoids

heterotrophic

euglena

eyespot

Red Algae

• Almost all red algae are __________• Red _________ absorbs small amounts of light

that is able to reach deep below the oceans surface.

• Red algae is used by humans in products such as _________, _________, and other nutrient rich foods in Asia.

multicellular

pigment

Ice cream conditioner

Green Algae

• Green algae contain ____________ and are very diverse.

• Green algae can be _________, form _________, or be multicellular.

• Live in either ____________ or __________.• Green algae and plants share the same type of

___________• There is a debate over whether green algae

belongs in the ______ kingdom.

Green pigment

unicellularcolonies

Fresh water Salt water

chlorophyll

plant

Brown Algae

• ____________ are brown algae.• Brown algae contain ________, ________,

_________, and _______ pigments.• Cool, rocky waters• Brown algae can form underwater _____ and

provide valuable habitat for underwater creatures.

• Some humans eat brown algae and use it in products such as thickeners in foods.

Sea weeds

brown greenyellow orange

forests

Fungi-like Protists

• Third group of protists (animal-like and plant-like protists)

• Fungus-like protists are _________, __________, and _________________.

• Three types of fungus-like protists include:• _________ - forest floors, moist shady places• __________ - decomposers of dead aquatic

organisms, parasites of fish and other animals• ___________ - parasites of many food crops

heterotrophs have cell wallsUse spores to reproduce

Slime molds

Water molds

Downy mildews

Fungi

• Characteristics of fungi:– _________ - organism whose cell contains a

nucleii– ____________ - other feeder– _____________ – ________________– _________________________

eukaryotes

heterotrophsAbsorb their food

Reproduce by spores

Need moist , warm places to grow

Cell structure

Fungi can be either _________ or ___________The cells of all fungi are surrounded by a

_______All fungi, except for yeast, have _____ -

branching thread-like tubes Hyphae are useful in the process of

____________

unicellular multicellular

Cell wall

hyphae

Food absorption

Obtaining Food

• First the fungi grow the _______ into the food source – ex. Fungi on dead trees

• Next, the hyphae release a chemical into the food source to help break the food down

• Then the hyphae ______ the food that has been broken down by the digestive chemicals that were released

hyphae

absorb

Reproduction

• Fungi reproduce by _____ - asexual and sexual• Fungi make spores _______ - cells at the tips of

the _______reproduce to form _______• Yeast is an exception – yeast cells reproduce

through _______ - similar to a bud growing on a tree branch – no spores are formed.

• _____________ - the hyphae of two fungi grow together and the genetic material is exchanged.

spores

asexuallyhyphae spores

budding

Sexual reproduction

Role of Fungi in Nature

• 1. _____________• 2. _________________ - decomposers• 3.________________ - penicillan• 4. _______________ - parasites on plants,

Dutch elm disease, corn smut, wheat rust, athlete’s foot, ringworm

• ______ - fungal and bacterial relationship – “pioneer” organisms.

Foods for people

Environmental Recycling

Disease fighting fungi

Disease Causing Fungus

Lichens

Lichens