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๐ŸงฌAP Biology Review

QR code for AP Biology practice questions

Bacteria & Viruses

๐ŸงฌAP Biology
Review

Bacteria & Viruses

Written by the Fiveable Content Team โ€ข Last updated September 2025
Verified for the 2026 exam
Verified for the 2026 examโ€ขWritten by the Fiveable Content Team โ€ข Last updated September 2025

Resources

In this session, we discuss bacteria and viruses. We begin by covering the purposes of learning about bacteria and viruses (students need to know the differences between the two and knowing these helps you understand the immune system). We begin with bacteria, highlighting that bacteria have all the characteristics of life (whereas viruses are not living things) and discuss the structure of bacteria and the 3 common shapes (spherical, rod-shaped and spiral). We cover 5 uses for bacteria and discuss pathogenic bacteria (harmful bacteria that makes up less than 1% of bacteria) and the diseases brought about by Pathogenic bacteria. We move on to viruses, discussing the 3 characteristics, the basic structure of viruses and how viruses work. We also explain the Lysogenic and Lytic cycles, as well as list some diseases caused by viruses. We also discuss protection against viruses, antibiotics (which target specific things but kill good bacteria), antivirals and vaccinations. We end the session comparing and contrasting viruses and living cells (structure, reproduction, genetic material, growth and development, how they obtain and use energy, response to environment and change over time).