Exam 5: Environmental Influences and Control of Microbial Growth

Why do some microorganisms produce antibiotics, and how do they avoid being harmed by the antibiotics they produce?

Which of the following is NOT true concerning irradiation of foods?

__________ are commonly used to control microbial growth in foods.

__________ enzymes are stable in part because they contain relatively low amounts of the amino acid glycine.

An organism that grows at the top of a tube of thioglycolate broth medium is probably a(n):

__________ have evolved to survive multiple extreme environments.

An organism that requires full oxygen tensions of 21% for growth is:

Describe the studies with Salmonella that showed that in vitro conditions do not always model what happens in vivo (in this case in the phagocytic vacuole).

Special channels for helping water move across the membrane quickly are called:

Why is oxygen so dangerous for cells and how do cells deal with these problems?

Why is death a logarithmic function and not an instantaneous event upon treatment?

The fastest growth rate for a species occurs at temperatures where a cell's __________ work most efficiently.

The proteins and cell components of halophiles have remarkably high intracellular levels of _________________, which helps to maintain their cell structure.

The D-value of a bacterial culture heated to 100°C is the time it takes to kill __________% of the population.

No one ever expected to find microbes thriving in our stomachs. What organism was found there, what problem does it cause, and how does it survive there?

Which category best describes E. coli?

Microbes accumulate __________ in the cell to prevent cell water loss in a hypertonic environment.

__________ is a measure of the number of solute molecules in solution and is inversely related to water activity.

Which of the following typically will survive autoclaving under standard laboratory operating conditions?

All of the following are true about microbes and temperature EXCEPT: