Microbiology Exam Study Guide: Step-by-Step Guidance

Q1. How do viruses compare with bacteria?

Background

Topic: Viruses vs. Bacteria

This question tests your understanding of the fundamental differences and similarities between viruses and bacteria, including their structure, replication, and roles in disease.

Key Terms and Concepts:

• Virus: A non-cellular infectious agent that requires a host cell to replicate.

• Bacterium: A unicellular, prokaryotic microorganism capable of independent life.

• Key differences: Structure, replication, metabolism, response to antibiotics.

Step-by-Step Guidance

1. List the structural differences between viruses and bacteria (e.g., presence of cell wall, organelles, genetic material).

2. Compare their methods of replication—consider which can reproduce independently and which require a host.

3. Discuss their metabolic capabilities—can they generate energy or synthesize proteins on their own?

4. Consider how each responds to antibiotics and why.

Try solving on your own before revealing the answer!

Q2. What role do viruses play in cancer development?

Background

Topic: Oncogenic Viruses

This question examines how certain viruses can contribute to the development of cancer in humans.

Key Terms and Concepts:

• Oncogenic virus: A virus that can cause cancer.

• Oncogene: A gene that has the potential to cause cancer.

• Transformation: The process by which a normal cell becomes cancerous.

Step-by-Step Guidance

1. Identify examples of viruses known to be associated with cancer (e.g., HPV, EBV, HBV).

2. Explain the mechanisms by which viruses can induce cancer (e.g., insertion of viral DNA, disruption of cell cycle regulation).

3. Discuss the difference between direct and indirect oncogenesis by viruses.

4. Consider the role of chronic infection and immune evasion in cancer development.

Try solving on your own before revealing the answer!

Q3. Discuss the structure of prions. Describe the mode of transmission, symptoms of disease, and any possible treatment for Creutzfeldt-Jakob disease (and variants).

Background

Topic: Prions and Prion Diseases

This question focuses on prions, their unique structure, how they cause disease, and specifics about Creutzfeldt-Jakob disease.

Key Terms and Concepts:

• Prion: An infectious protein that can cause neurodegenerative diseases.

• Creutzfeldt-Jakob disease (CJD): A fatal prion disease affecting the brain.

• Transmission: How prion diseases are spread (e.g., contaminated instruments, ingestion).

Step-by-Step Guidance

1. Describe the structure of a prion and how it differs from viruses and bacteria.

2. Explain how prions replicate and spread within the host.

3. List the common modes of transmission for CJD and its variants.

4. Summarize the typical symptoms and disease progression.

5. Discuss current treatment options and their limitations.

Try solving on your own before revealing the answer!

Q4. Discuss the steps of viral replication. What is the difference between lytic and lysogenic replication?

Background

Topic: Viral Replication Cycles

This question tests your knowledge of how viruses reproduce and the differences between two major replication cycles.

Key Terms and Concepts:

• Lytic cycle: Viral replication that results in host cell lysis and release of new virions.

• Lysogenic cycle: Viral DNA integrates into the host genome and replicates along with it.

• Steps: Attachment, penetration, biosynthesis, maturation, release.

Step-by-Step Guidance

1. List and briefly describe each step of the viral replication process.

2. Compare what happens to the host cell in the lytic versus lysogenic cycle.

3. Explain the significance of prophage formation in the lysogenic cycle.

4. Discuss how environmental factors can trigger a switch from lysogenic to lytic cycle.

Try solving on your own before revealing the answer!