1. 7th Grade - Mrs. Boguslaw Microorganisms, Fungi, and Plants Chapter 2
Bacteria and Viruses
7th Grade - Mrs. Boguslaw
Microorganisms, Fungi, and Plants Chapter 2

2. Bacterial Cell

3. Bacterial Cell
Capsule: extra protection for the cell

4. Bacterial Cell
Cell Wall: support and structure for the cell

5. Bacterial Cell
Cell Membrane: controls nutrients and wastes entering and leaving the cell

6. Bacterial Cell
Cytoplasm: fluid that fills the cell

7. Bacterial Cell
Nucleoid: central region of DNA

8. Bacterial Cell
Ribosomes: make proteins

9. Bacterial Cell
Flagella: helps the cell move through the environment

10. Bacterial Cell
Pili: allow bacteria to attach to surfaces, including other bacteria

11. Three Common Shapes Bacilli - rod shaped, large surface area
Pro: helps take in nutrients
Con: dries out easily

12. Three Common Shapes Cocci - spherical
Don’t dry out as quickly as rod- shaped

13. Three Common Shapes Spirilla - long and spiral- shaped
Use flagella at both ends to move like a corkscrew

14. Bacterial Reproduction
Binary fission
asexual
single-celled organisms only
one cell divides into two cells that are the same size

15. Endospores Most bacteria like warm, moist places
If it’s dry or cold, some bacteria will die…others will become inactive and form endospores
Endospore: thick protective spore that forms inside a bacterial cell and resists harsh conditions
When conditions improve, endospore breaks open and bacteria becomes active again

16. How are bacteria classified?
By how they get food
Decomposers, Consumers, or Producers

17. Cyanobacteria Producers Usually live in water
Can have different pigments to help in photosynthesis - green, blue, red
Scientists theorize that plants may have come from cyanobacteria living inside larger cells - bacteria provided food, cells provided protection

18. Archaea
Live in EXTREME environments, often where nothing else can live
Different from bacteria - might not have a cell wall, and if they do, it is chemically different
Three main types:
heat lovers - ocean vents and hot springs
salt lovers - Great Salt Lake, Dead Sea
methane makers - swamps and animal intestines

19. Bacteria’s Role in the Environment
Chapter 2, Section 2

20. Good for the Environment
Nitrogen Fixation
Nitrogen gas makes up 78% of the air, but most plants can’t use it directly
Nitrogen-fixing bacteria take in air from the environment and change it to a form plants can use

21. Good for the Environment
Recycling
Decomposer bacteria break down dead plant and animal matter
This makes nutrients available for other living things

22. Good for the Environment
Cleaning up
Bioremediation: the biological treatment of hazardous waste by living organisms
Changes harmful chemicals into harmless ones
Cleans up hazardous waste from industries, farms, and cities
Can clean up oil spills

23. Good for People Bacteria in Food
Lactic-acid producing bacteria break down the sugar in milk, which adds flavor and preserves the food
Cheese, yogurt, buttermilk, sour cream
Other non-dairy foods: sauerkraut, sourdough bread, olives, dill pickles, soy sauce, salami

24. Good for People Making medicines
Antibiotics: medicine used to kill bacteria and microorganisms
Many antibiotics are actually made by bacteria

25. Good for People Making medicines
Insulin - used by the human body to break down and use sugar and carbohydrates
People with diabetes do not make enough insulin
Scientists put genes to make insulin into bacteria - they then separate the bacteria from the insulin and give the insulin to people who have diabetes

26. Good for People Genetic engineering
Scientists can change the genes of bacteria by adding genes from other organisms
We can engineer bacteria to make many products, including insecticides, cleansers, and adhesives

27. Harmful Bacteria Pathogenic bacteria: bacteria that cause disease
Pathogenic bacteria get inside a host organism and take nutrients from the host’s cells
Vaccines and antibiotics are ways humans fight

28. Harmful Bacteria
Bacteria can attack plants, animals, protists, fungi, and even other bacteria
Can damage crops
Odd colored spots and soft rot in plants can be caused by bacteria

29. Viruses
Chapter 2, Section 3

30. Virus
a microscopic particle that gets inside a cell and often destroys the cell
tiny, smaller than the smallest bacteria
5 billion virus particles could fit in a drop of blood
Change VERY rapidly
Hard to fight

31. Are viruses alive?
If something is alive, what can it do?

32. Are viruses alive?
Viruses contain protein and genetic material, but can’t…
eat
grow
break down food
use oxygen
Reproduce on their own

33. Are viruses alive?
…no.

34. Are viruses alive? A virus cannot function on its own
needs a host to survive and reproduce
host: an organism from which a parasite takes food or shelter
Viruses use a host’s cell as a tiny factory - forces cell to make viruses instead of healthy new cells

35. Classifying Viruses
Viruses can be grouped by their shape, the type of disease they cause, their life cycle, or the kind of genetic material they contain (DNA or RNA).
Every virus is made of genetic material inside a protein coat
Protein coat protects the genetic material and helps a virus enter a host cell
Many viruses have a protein coat that matches the characteristics of their particular host

36. Virus shapes Four main types: Spacecraft (Bacteriophage) Cylinder
Crystal
Spheres

37. Lytic Cycle
A virus attacks living cells and turns it into a virus factory

38. Lysogenic Cycle
Virus acts as a “time bomb” - puts in its genetic material but doesn’t build virus parts; each time the cell divides it passes down the virus’ instructions.
May enter the lytic cycle at any time

39. Lysogenic Cycle

40. Treating a Virus Antibiotics DO NOT work!
Antiviral medications can stop viruses from reproducing
Because many viral diseases do not have cures, prevention is key - vaccines, good hygiene, staying away from wild animals
If you’re sick, rest and get plenty of fluids