• Microbes are beneficial in different ways.
  
  
• Microbes that possess virulence factors are pathogens.
  
  
• Epidemiology is the study of factors that influence transmission and distribution of diseases in a population.

1. How do microbes directly benefit you?
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2. What makes some microbes virulent?
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3. What are the different ways you can catch an infectious disease?
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• Viruses are not cellular and have to reproduce inside a living host.
  
  
• Viruses cause many human diseases such as influenza, the common cold, and measles.
  
  
• Prions are infectious proteins that can cause disease.

1. Are viruses alive? How can they replicate?
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2. Why aren't you always immune to influenza even if you had it before?
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3. What diseases are caused by herpes viruses?
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4. What does chickenpox have to do with shingles?
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Essential Study Partner

• Characteristics of Viruses
• Viral Replication

Concept Quiz

• Viruses

Bioethical Focus

• Testing of HIV Vaccines

• Bacteria are single celled organisms that lack a nuclear membrane and other membranous organelles.
  
  
• Bacteria can be categorized as gram-positive or gram-negative.
  
  
• Bacteria cause many human diseases including strep infections, food poisoning, and tuberculosis.

1. What is the structure of bacteria and how does the cell wall of bacteria differ?
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2. What complications are possible after a strep infection?
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3. Why is tuberculosis on the rise today?
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4. What are the two major types of food poisoning?
   Answer

Essential Study Partner

• Characteristics of Bacteria
• Diversity of Bacteria

Art Labeling Activity

• Bacterium Cell (27.0K)

• Fungi, protozoans, and worms can also cause disease.

1. What types of diseases are caused by fungi?
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2. What is the most widespread and dangerous protozoan disease?
   Answer
   
   
3. Why isn't schistosomiasis prevalent in this country?
   Answer