1. Viruses, Bacteria, Protists, Fungi
Chapter 7
Grade 7 Science

2. 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

3. Structure of Viruses Viruses have three distinct shapes: _________
All viruses have two basic parts:
1. A __________ that protects the virus
2. A ___________ made of genetic material
round
rods
threads
Protein coat
Inner core

4. 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

5. 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

6. 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

7. 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
Drops of moisture
bites
Body fluids
Vaccine
preventative

8. 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

9. Bacteria – Structure

10. Bacteria - Size

11. Obtaining Food and Energy
Bacteria must have :
_____________
______________
Some Bacteria are __________ - self feeders
Bacteria make their food in 2 ways:
_______________________________________
Some bacteria are __________ - other feeders that feed on other organisms or the food that other organisms make.
Source of food
Energy supply
autotrophs
Suns energy
Energy from chemical substances in the environment
heterotrophs

12. 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

13. Reproduction Bacteria need the following for reproduction: ___________
_______________
________________ - 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
food
temperature
Suitable conditions
Asexual Reproduction
Binary fission

14. 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
heating
drying

15. 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 cleanup
Health maintenance
Medicine Production
Autotrophic bacteria
stable

16. 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

17. 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.
Decomposing bacteria
roots
Nitrogen-fixing bacteria

18. 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

19. 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
protozoans
heterotrophs
unicellular
move
live

20. 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

22. 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

23. 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

25. 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
mutualism
symbiosis

26. Protozoans that are Parasites

27. 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
reproduction
multicellular

28. 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

29. 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

30. 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

31. 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

32. 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
unicellular
colonies
Fresh water
Salt water
chlorophyll
plant

33. 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
green
orange
yellow
forests

34. 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 walls
Use spores to reproduce
Slime molds
Water molds
Downy mildews

35. Fungi Characteristics of fungi:
_________ - organism whose cell contains a nucleii
____________ - other feeder
_____________
________________
_________________________
eukaryotes
heterotrophs
Absorb their food
Reproduce by spores
Need moist , warm places to grow

36. 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

37. 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

38. 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
asexually
hyphae
spores
budding
Sexual reproduction

39. Role of Fungi in Nature 1. _____________
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

40. Lichens