1. Chapter 19 Viruses and Bacteria

2. Viruses Viruses are NOT cells! A virus is made up of: Nucleic acid
(RNA or DNA)
2. Protein coat

3. Bacteriophage = virus that
What is a virus?
Made of nucleic acid (DNA OR RNA), protein coat (capsid) and sometimes lipids
MUST enter living cells in order to reproduce
Very small
Range from a few to 100s of genes
Bacteriophage = virus that
infects bacteria

4. Viruses: Living or Non-living?
No cell membrane or other living cell components
Host cells required for reproduction
Do not metabolize or respond to stimuli
BUT, they do have genetic info and can change over time
NON-LIVING!!!!

5. Virus Infection: Lytic vs. Lysogenic Cycles
Lytic Cycle: virus enters cell, makes copies of itself, and causes the cell to “lyse” or burst
Lysogenic Cycle: virus integrates into host cell DNA and viral genetic info is copied along with host cell’s DNA

6. Lytic Cycle
The viral infection that rapidly kills the host cell is the lytic cycle.

7. Lytic Cycle of a Cold or Influenza Virus
The cold or flu virus infects cells lining of the nose and throat, reproducing more cold viruses and destroying body cells.

8. What are the two things all viruses have?
Are viruses living or non-living?
What are the two ways viruses infect a living host cell?
What are the two ways viruses can reproduce?

9. Review Lytic and Lysogenic Cycles…

10. Retrovirus A virus that contains RNA instead of DNA
CAPSID
A virus that contains RNA instead of DNA
Human Immunodeficiency Virus (HIV) is a retrovirus
HIV causes AIDS
ENVELOPE
RNA

11. HIV Virus and Immune System
The thymus gland by the heart and the bone marrow produce the white blood cells that protect us from infection.
HIV attacks the T cell of the immune system.

12. Retroviruses
When enter cells, produce DNA copy of RNA then integrate into host cell
Can remain dormant until replicate and burst open cell
“Retro” because genetic info is copied backwards RNA => DNA

13. Destroys helper T cells
Makes getting other diseases really easy
Transmitted by blood, breast feeding, sexually, and other bodily fluids
Can happen to anyone!
Mouth sores common to AIDS patients

14. Viruses as Parasites
Take advantage of host cell’s respiration, nutrition and other cellular functions
Depends entirely on another organism for its existence

15. Types of Viral Diseases
Must know
Names
Symptoms
Transmission

16. West Nile Symptoms Transmitted by Fever Headache Body ache
infected mosquitoes

17. Chicken Pox Symptoms Transmitted by Fever and weakness Red, itchy rash
Direct contact
Droplet inhalation

18. Common Cold Symptoms Transmitted by Sneezing Sore throat Fever
Muscle and headaches
Transmitted by
Direct contact
Droplet inhalation

19. Warts/HPV Symptoms Transmitted by
Noncancerous growths on skin; can become cancerous
Transmitted by
Direct contact
Sex

20. Hepatitis Symptoms Jaundice Fatigue Abdominal pain Diarrhea and nausea
Transmitted by
Human waste, contaminated food and water (Hep A)
Contact w/ bodily fluids (B & C)

21. Herpes Symptoms Transmitted by
Blister like sores (can actually be on any part of the body)
Fever
Fatigue
Transmitted by
Direct contact
Sex

22. Measles Symptoms Transmitted by High fever Sore throat Rash
Swollen eyelids
Transmitted by
Droplet inhalation

23. Polio Symptoms Transmitted by Fever Headache Muscle weakness
Difficulty swallowing
Transmitted by
Droplet inhalation

24. Smallpox Symptoms Transmitted by High fever Fatigue Rash Contact
Droplet inhalation

25. Virus Prevention Vaccination Hygiene Safe sex Abstinence
Injection of weakened or dead pathogen
Hygiene
Wash your hands!
Safe sex
Use condoms or other
prophylactic contraceptives
Abstinence
Only method that is 100% effective against transmission of sexually transmitted viruses

26. Bacteria Bacteria are small PROKARYOTIC cells.
They have a cell wall and DNA.
Some bacteria are beneficial and some are pathogenic.
*Pathogenic = disease causing

27. Bacteria Used as a common name to describe prokaryotes
Usually range from 1-5 micrometers!
Divided into two kingdoms: eubacteria and archaebacteria
Staphylococcus epidermidis

28. Eubacteria Largest bacterial Kingdom
Wide range; many lifestyles, live almost anywhere
Usually have cell wall for shape and protection - cell wall contains peptidoglycan
Have cell membrane- sometimes an extra membrane outside of it as well
Escherichia coli

29. Archaebacteria
Look similar to eubacteria under microscope but chemically different
No peptidoglycan & different membrane lipids
DNA more like eukaryotes (Share a more recent common ancestor)
Live in extreme/harsh environments

30. How Are Bacteria Identified?
Identified by:
Shape
Movement techniques
Way of obtaining energy
Oxygen Needs
Mode of Reproduction

31. Shape Rod-shape: Bacilli Spherical shape: Cocci
Spiral and corkscrew: Spirilla

32. Movement Not all prokaryotes can move Ones that move
Propelled by flagella (whiplike structures for movement)
Lash, snake or spiral
Glide along layer of slime
Escherichia coli

33. Metabolic Diversity: Heterotrophs vs. Autotrophs
Most are heterotrophic!
If autotrophic:
Some are photoautotrophs (similar to plants)
Some are chemoautotrophs (make organic molecules from CO2
If heterotrophic:
Most are chemoheterotrophs (Take in organic molecules for energy and carbon supply)
Humans are chemoheterotrophs, too!
Some are photoheterorophs (photosynthetic but need organic compounds for carbon source)

34. Oxygen Needs Facultative anaerobes Obligate anaerobes Obligate aerobes
Can survive with or without oxygen
Obligate anaerobes
Must live in the absence of oxygen
Obligate aerobes
Require constant supply of oxygen to live

35. Growth and Reproduction
Conjugation
Hollow bridge forms between two cells and genes move from one cell to the other; increases genetic diversity
IS a sexual process (NOT REPRODUCTION – does not produce gametes)
Binary Fission
Grows to where it doubles in size then replicates DNA and divides in half

36. Bacteria’s Importance
Producers
Nitrogen Fixation
Human Uses
Food and beverage production
Industry
Drug and chemical production
Live in our intestines; provide vitamins
Biotechnology
Decomposers
Recycle nutrients in ecosystem
Sewage treatment

37. Bacterial Diseases Two ways bacteria causes diseases:
Break down organism’s cells for food
Release toxins that affect the organism’s body

38. Examples of Bacterial Diseases
Streptococcus
Symptoms – fever, sore throat, swollen glands
Diphtheria
Symptoms – sore throat, low grade fever
***Both cause disease by releasing TOXINS

39. Circulatory System
Bacteria can infect the heart valves and the lining of the ventricles.
The circulatory system brings oxygen and nutrients to all body cells.
Left ventricle

40. Beneficial Bacteria in the Digestive System
Bacteria like E. coli make digestive enzymes and vitamin K in the large intestine.

41. Nervous System
Brain
Spinal cord
The nervous system responds to changes in the external and internal environment. It is “the communicator”.
Spinal& peripheral nerves

42. Nervous System Infections
Both bacteria and viruses can infect the brain causing such diseases as meningitis and encephalitis.
Nerve cells or Neurons

43. Controlling Bacteria Food storage and processing Disinfectants
Chemical solutions that kill bacteria
Sterilization
Method to control growth of bacteria by heat
Vaccines
Weakened or killed pathogens
Sometimes prompts body to produce immunity
Antibiotics
Block growth of bacteria

44. Comparing VIRUSES and BACTERIA
Which is a virus?
Which is a bacteria?
Which is living?
Which is non-living?

45. Kingdoms LIST THE 6 KINGDOMS GIVE 2 DETAILS FOR EACH ONE….EX:
prokaryotic or eukaryotic?
autotroph or heterotroph?
cell wall or no cell wall?
unicellular or multicellular?
What kingdom is a virus in?