AP-Micro Microbiology: Microbial Ecology and Pathogenesis 2

Question 1

Which term describes the relationship where one organism benefits and the other is neither helped nor harmed?

Accepted Answer

Commensalism

Answer

Commensalism is a symbiotic relationship in which one partner benefits while the other experiences no significant effect.

Question 2

A bacterium that can only cause disease when the host's immune system is compromised is classified as a:

Accepted Answer

Opportunistic pathogen

Answer

Opportunistic pathogens exploit immunocompromised states and do not normally cause disease in healthy hosts.

Question 3

The term 'Koch's postulates' refers to criteria used to:

Accepted Answer

Establish causation between a microbe and a disease

Answer

Koch's postulates provide a logical framework for proving that a specific microorganism is the causative agent of a specific disease.

Question 4

Which of the following best describes a biofilm?

Accepted Answer

A structured community of microbes encased in a self-produced matrix

Answer

Biofilms are structured microbial communities embedded in an extracellular polymeric substance (EPS) matrix attached to surfaces.

Question 5

Nitrogen fixation in ecosystems is primarily performed by:

Accepted Answer

Certain bacteria and archaea

Answer

Prokaryotes such as Rhizobium, Azotobacter, and certain cyanobacteria contain nitrogenase and can fix atmospheric N₂ into usable ammonia.

AP Practice Test