Isolated and purified hepatitis B virus surface antigen can be used to synthesize ________ vaccine.

Activation of C3a results in ________.

The classical pathway for complement activation is initiated by:

A patient infected with a new virus shows strong NK-cell activity on day 2 but no CTL response yet. Which is the best explanation?

All of the following contribute to a pathogen's pathogenicity except:

Some antimicrobial chemicals are considered disinfectants and antiseptics.

Differentiate exotoxins and endotoxins in the following aspects (5 points): 

Source – Which types of bacteria produce each?

Chemical composition – What are they made of? 

Heat stability – Are they heat-stable or heat-labile?

Toxicity and lethality – Which is more potent and lethal, and why?

Mechanism of action – How are they released? How do they cause damage to host cells?

Examples of diseases – Name at least one disease caused by each.

Choose 2 out of the 3 questions to answer. If you answer all 3, the last question will automatically be skipped for grading. (4 points each, 8 points in total)

 a, Select one DNA or RNA virus family and a representative human virus from that family. Describe:

The virus family name and genome type (DNA/RNA, single or double-stranded, enveloped or non-enveloped).

The disease(s) it causes and its main route of transmission.

Whether the infection is acute, chronic, latent, or persistent, and how this relates to its viral replication mechanism.

One treatment or prevention strategy (e.g., antiviral, vaccine, or public health measure) and why it is effective.

b. Define the term virulence as it applies to a pathogen, and explain how it contributes to disease severity. Address the following points:

Definition – What is virulence, and how is it different from pathogenicity?

Factors influencing virulence – Name 4 pathogen traits that affect virulence 

Mechanisms countering host defenses – Name and explain at least two ways pathogens increase virulence by evading or resisting host defenses 

Example – Provide one pathogen example that demonstrates one or more of these virulence factors.

c. Differentiate between vertical and horizontal gene transfer in bacteria. Address the following points:

Definition and direction of transfer

Vertical gene transfer: describe how genetic material is inherited from parent to offspring during reproduction.

Horizontal gene transfer: name and briefly describe the three main mechanisms. 

Bioengineering application -- Identify which process is most commonly used to create recombinant bacteria and explain why it is useful in genetic engineering.

Name two classes of antimicrobial drugs and compare them in the following aspects (5 points):

Drug class name – Identify each antimicrobial class.

Targeted microbes – What type of microbe does each drug act against (bacteria, fungi, virus, or parasite)?

Mechanism of action – How does each drug interfere with microbial survival (e.g., inhibits cell wall synthesis, protein synthesis, nucleic acid synthesis, or cell membrane function)?

Example drug – Provide one example from each class.

Example disease treated – State at least one infection or condition each drug is commonly used for.

Explain the endosymbiotic theory and summarize the evidence supporting it. Address the following points (3 point):

Definition – What does the endosymbiotic theory propose about the origin of eukaryotic cells?

Key events – Which organelles are believed to have originated through endosymbiosis?

Evidence – Describe at least three pieces of evidence that support the theory and provide one example of a modern eukaryotic organelle that supports this theory.