viruses, bacteria, protists, fungi chapter 7 grade 7 science
TRANSCRIPT
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
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
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