1. What are these tiny particles? Pages 210 - 215
Viruses
What are these tiny particles?
Pages

2. 1.What is a Virus?
A tiny non-living particle that invades and then multiplies inside a living cell.
They are NOT cells
Do NOT have characteristics of organisms

4. 2. What does a virus need in order to multiply?
Viruses need a host that they can multiply within
The only way viruses are like organisms is that they can multiply
Host: A living thing that provides a source of energy for a virus or an organism.

6. 3. How is a parasite like a virus?
PARASITE: Organisms that live on or in a host and cause harm to it.
Viruses and parasites are similar because they both have hosts that they depend on for energy.
Almost all viruses destroy
their host cells!!!!

7. Parasite Examples Parasite living inside a human HOST
Parasite living on the outside of a
caterpillar HOST

8. 4. Characteristics of Living Things
1. Made of cells
2. Composed of Chemicals
3. Use Energy
4. Respond to Stimuli
5. Grow and Develop
6. Reproduce (Make more of themselves)
Mrs. Carey’s Fabulous Four
1.Reproduction
2.Metabolism
3.Response
4. Growth

9. Characteristics of Living Things
REMEMBER,THE
ORGANISM MUST
HAVE ALL OF THE
CHARACTERISTICS TO BE
CONSIDERED LIVING!

10. 5. Viruses, Living or Non-living?
NON-LIVING!!!! They do not have all the characteristics of living things!!!!
They MULTIPLY, no REPRODUCE!!!!!

11. 6. Structure Viruses come in various shapes and sizes A. Round B. Rod
C. Bricks
D. Thread
E. Bullets

12. Shapes of Viruses

13. Structure of Viruses 7. Some of more complex, like the bacteriophage.
BACTERIOPHAGE: A virus that only infects bacteria.

14. Bacteriophages Continued
8. Bacteriophage literally means “ bacteria eater”.

15. Capsid: Protein shell of a virus

16. Virus Similarities
9. Even though all viruses look different from each other, they all have similar structure.
10. Virsuses have two basic parts:
A. Protein Coat: Protects the virus
B. Inner Core: Made of genetic material
* A virus’s genetic material contains the instructions for making more viruses. *

17. Virus Structure

18. 11. Protein Coat Each virus contains a unique protein coat.
12. Like keys, virus’s proteins only fit into certain “locks” or proteins.
Only specific viruses fit with specific host cells.

19. Protein Coat
Example: Most cold viruses only affect cells in the nose and throat of humans.

20. How Viruses Multiply?
13. Once inside a cell, a virus’s genetic material takes over most of the cell’s functions.
Genetic material = DNA
The genetic materials instruct
the cell to produce virus’s proteins
and genetic material.

21. How Viruses Multiply? 15. Viruses cannot multiply without a HOST!
16. Active virus enters cells and immediately being to multiply.
Example: Like a copy machine left in the “on” position.

23. Lytic Cycle

24. Lytic Cycle – ACTIVE Viruses
Step #1 - Attachment: Virus attaches to the surface of a host cell
Step #2 - Injection: Virus injects genetic material into host cell
Step #3 - Production: Virus’s genetic material take over host cell and starts to produce proteins and genetic material
Step #4 - Assembly: Proteins and genetic material assemble new viruses
Step #5 - Release: Host cell bursts and releases new viruses

25. “Hidden Viruses”
18. Hidden viruses do not immediately become active. Instead the “hide” for a while.

26. Lysogenic – “Hidden” Viruses”
Step #1 - Attachment: Virus attaches to the surface of a host cell
Step #2 - Injection: Virus injects genetic material into host cell
Step #3 – Absorb/Incorporate: Virus’s genetic material becomes part of the host cells.
Step #4 – Separation: After some time, virus’s genetic material removes itself and becomes ACTIVE!
Step #5 – Production & Assembly: Cell produces new viruses
Step #6 - Release: Host cell bursts and releases new viruses

27. Lysogenic Cycle “Hidden Viruses”
Under certain conditions, the virus is activated!
Can stay in inactive state for years!
Example: Cold Sore – Virus remains hidden for years or months until it is activated. Then the result is a red and swollen area near the mouth.
VIRUSES MULTIPLY NOT REPRODUCE!!

28. Viruses and Diseases 20. Diseases can be spread in a variety of ways:
A. Direct contact with contaminated objects
B. Bites from infected animals (rabies)
C. Air born (Tiny droplets of moisture)
D. Contact with body fluid (blood)

29. Viruses and Diseases
21. There are currently no cures for viral diseases.
22. Over-the-counter medications simply relieve the symptoms.

30. Virus Treatment
23. The best treatment resting, drinking plenty of fluids, and eating a well balanced meals.
Staying away from other potential ways that diseases can spread.
Follow the food pyramid
Getting 8 full hours of sleep

31. Preventaion 24. One way to prevent getting sick is a vaccine.
25. Vaccine: A substance used in a vaccination that consists of a weakened or killed pathogen that can trigger the immune system into action.
By receiving a small portion of the virus, your body will learn how to fight it off. If your body comes in contact that virus again, it should know how to fight it off.

32. Prevention and Health
26. Another way to prevent disease is to keep your body healthy.
27. You can keep your body healthy by:
Working out
Eating healthy
Getting plenty of sleep

33. Vaccines 28. Why don’t vaccines cause diseases themselves?
They are a smaller portion, so a normal body can fight off and not get infected.
Dead portion of a pathogen so can no longer multiply.

34. What’s next?
What are Bacteria?

35. Bacteria!

36. The Bacteria Cell 1. Bacteria are: Prokaryotes (NO nucleus)
Single-celled
2. Discovered by accident by Leeuwenhoek
(first person to look at living things
under the microscope)

37. 3. Prokaryote or Eukaryote
Prokaryote: Lacks a nucleus
Eukaryote: Had a nucleus
Bacteria do NOT
have a nucleus so they are PROKARYOTES!

38. 4. Parts of a Bacterial Cell
Exterior View
1. Flagellum – Used for movement
Interior View
2. Ribosomes – Make proteins
3. Cell Wall – Used for Structure
4. Cell Membrane
5. Cytoplasm
6. Genetic Material – DNA

39. 4. Parts of a Bacterial Cell

40. Bacteria Movement
5. Some bacteria have a flagellum, which is a long, whip-like structure that can help a cell move.
6. Bacterial cells without a flagella cannot move on their own.

41. Bacteria Movement
7. Ways that bacteria can be carried from one place to the next:
A. Air
B. Water currents
C. Other objects

42. Bacteria Size 8. Bacteria vary greatly in size.
A. Size of the period at the end of a sentence.
B. One millionth of a meter

43. Bacteria Size

44. 11. Bacteria Shapes
Spiral Rod/Pill Round

45. Cocci
Found in pond scum

46. Bacilli Found in Yogurt

47. Spirilla
Found in Hot Springs

48. Obtaining Food and Energy
12. Bacteria must have a source of food and a way of breaking down the food to release its energy.
13. Some bacteria are autotrophs, which means they can make their own food.
14. Autotrophs can make their food in one of two ways:
Some capture sunlight (like plants)
Energy from chemical substances

49. Obtaining Food and Energy
15. Heterotroph: Organisms that do not have the ability to make their own food
Must consume energy! (Eat Food!)
16. Heterotrophic bacteria get food by:
Consuming milk and meat to decaying leaves

50. Obtaining Food and Energy
17. Bacteria need a constant supply of energy!
18. Bacteria get this energy by:
Breaking down food in process of respiration
Most bacteria need oxygen to break down food
A few bacteria will die in presence of bacteria

51. Obtaining Food and Energy
Aerobes: Need oxygen to break down food
Anaerobes: Do NOT need oxygen to break down food.
These bacteria will die if oxygen is present

52. Reproduction 19. Bacteria will reproduce frequently when:
Plenty of food
Right temperature
Other suitable conditions
20. Under the ideal conditions, bacteria can reproduce as often as every 20 minutes! (Doubling their population size!)

53. Asexual Reproduction
21. Asexual Reproduction: A reproductive process in which one cell divides to form two identical cells.
22. Binary Fission is a form of asexual reproduction.
23. During binary fission, a cell duplicates its genetic material, and then divides into two separate cells.

54. Sexual Reproduction 24. Some bacteria can also reproduce sexually.
25. Sexual Reproduction: Reproductive process where two parents combine their genetic material to produce a new organism, different from both parents.
26. Bacteria use a form of sexual reproduction called conjugation.

55. Conjugation

56. * CONJUGATION DOES NOT INCREASE THE NUMBER OF BACTERIA!*
27. During conjugation, one bacterium transfer genetic material to another using a thread like bridge.
* CONJUGATION DOES NOT INCREASE THE NUMBER OF BACTERIA!*

57. Endospore Formation
28. If conditions are unfavorable for bacterial growth, bacteria can form an endospore.
29. An endospore is a thick, rounded, thick- walled resting cell that forms inside a bacterial cell.
30. Endospore resists against:
Freezing
Heating
Drying

58. 31. Endospores are so light they can be carried by wind.
Endospore Formation
31. Endospores are so light they can be carried by wind.