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2.3 Microbial Variation 〰️➰➿

microbiological variation

Introduction to microbial variation

Microbiological variation is a core JC1 topic in H2 BIO A levels. This topic follows the processes of how bacteria and viruses evolve. Bacteria utilizes horizontal gene transfer of which there are 3 mechanisms. Viruses utilizes antigenic drift as well as shift instead. This evolution is important to microbes because it contributes to their survival fitness. Therefore, it allows them to bypass host defenses so that they can replicate, which results in disease in humans.

Because of their impact in human health, this topic is also an important foundation towards the extension topics, immunology as well as infectious diseases.

Phrasing errors

  • F plasmid allows for the production of a sex pilus.
  • Transformation is the uptake of naked DNA from the external environment.
  • There are 2 types of plasmids F+ and F. F+ plasmid is transferred to F plasmid.
  • Plasmids undergo replication within the F+ cell and transfers the double stranded plasmid into the F cell via conjugation tube.

Exam tips

  • Origin of replication ≠ origin of transfer.
  • In bacterial horizontal gene transfer, remember there is always a donor and recipient, clarify this relationship clearly in your answers.