BIO201- Ch7 Review

The figure shows a typical bacterial growth curve with the y-axis indicating the log of the number of bacteria and the x-axis indicating time in culture. In the figure, which section (or sections) of the graph illustrate an exponential change in cell numbers?

• A and B

• B and C

• B and D

• A and C

• C and D

Tags

NGSS.HS-LS2-4

Which section (or sections) of the graph would be expected to illustrate a growth phase where the number of cells dying equals the number of cells dividing?

• A only

• A and C

• B only

• C only

• B and D

Tags

NGSS.HS-LS1-4

In which phase would you expect to observe the MOST endospores in a Bacillus cell culture?

• death phase

• lag phase

• log phase

• log, lag, and death phases would all have roughly the same number of endospores.

During which phase would penicillin, an antibiotic that inhibits cell-wall synthesis, be most effective?

• Death phase

• Lag phase

• Log phase

• Stationary phase

If a culture starts with 50 cells, how many cells will be present after five generations with no cell death?

• 100

• 250

• 500

• 1600

• 3200

Tags

NGSS.HS-LS1-4

Which of the following environments would harbor psychrophiles?

• mountain lake with a water temperature of 12 °C

• contaminated plates left in a 35 °C incubator

• yogurt cultured at room temperature

• salt pond in the desert with a daytime temperature of 34 °C

A soup container was forgotten in the refrigerator and shows contamination. The contaminants are probably which of the following?

• thermophiles

• acidophiles

• mesophiles

• psychrophiles

An organism has an optimal growth rate when the hydrogen ion concentration is very low. This organism is a(n)...

• osmotolerant

• acidophile

• alkalophile

• aerotolerant anaerobe

• neutrophile

A microbiology student noticed that a culture broth tube was very turbid at the surface but clear throughout the rest of the tube. She can conclude that the...

• organisms are aerobes.

• organisms should be grown in an anaerobic chamber.

• organisms cannot produce superoxide dismutase and/or catalase.

• organisms cannot tolerate oxygen.

• broth is sterile.

Tags

NGSS.HS-LS2-3

In order to look for bacteria that degrade petroleum, a culture medium containing crude oil, sodium nitrate, phosphate buffer, and magnesium sulfate are inoculated with soil. This medium is:

• Chemically defined

• Simple

• Complex

• Liquid