Category: Uncategorized

Which bacteria caused a problem for the fast food chain Jack in the Box in 1993?

Although the inner leaflet (half) of the gram-negative outer membrane is composed mainly of phospholipids, the outer leaflet of the outer membrane contains

All of the following are true about Pseudomonadaceae except:

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 isolated a cell that possesses the following: ribosomes, double-stranded DNA, and a cytoplasmic membrane composed of a phospholipid bilayer. Without any additional information, into which domain of living organisms would you classify this cell?

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.

Bacteria can have positive, neutral, or negative effects on humans and other macroorganisms. Which of the following would be a negative association?  

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

Consider the following chemical reaction:  C6H12O6 + 6O2 → 6CO2 + 6H2O  ΔG’ = -686 kcal/mol Which of the following statements is correct?