The HIV virus is an example of a(n):

In what cavity is the brain found?

The plaque (microbial biofilm) that forms between your teeth is a highly anaerobic (oxygen-free) environment, even though the mouth is one of the most aerobic habitats in the body and most of the bacteria living there can use oxygen if it is available. Why is there no oxygen in the plaque between your teeth?

You have a pure culture of a given bacterium, and you want to determine its CFU, so you perform the following steps: Take 1 mL from the pure culture and add it to 9 mL of sterile saline in test tube 1; mix. Take 0.1 mL from test tube 1 and add it to 9.9 mL of sterile saline in test tube 2; mix. Take 0.1 mL from test tube 2 and add it to 9.9 mL of sterile saline in test tube 3; mix. Take 0.1 mL from test tube 3 and add it to the surface of a solid medium in a plate using the spread-plate method. Repeat step 4 using a second plate to obtain a duplicate. Incubate for 24 hours. After incubation, you count 178 colonies on one plate and 165 colonies on the other. What is the calculated CFU of the original pure culture?

Consider the following image showing the electron transport chain complexes that can be found in Escherichia coli.    Knowing that ATPase needs approximately 3.3 H+ to make 1 ATP molecule, how many more ATP molecules per NADH will be produced by E. coli when oxygen is used as the final electron acceptor compared to nitrate.

Gram staining is useful for bacterial identification. Which of the following is another way it is most useful?

Which of the groups listed below are prokaryotes that tend to be found in more extreme environments and are therefore commonly known as extremophiles?

A “redox tower” shows the redox potential of common metabolic half reactions. The tower predicts likelihood or relative gains from a reaction because:

Which of the following types of microscopy could be used to visualize the layers of the cell membrane and the cell wall?

Arrange Koch’s postulates in the correct order.