A bacterial broth culture is diluted by a factor of 100,000, and 0.1 mL of the dilution is spread over the surface of an agar plate. The next day, 123 colonies are observed on the plate. What was the concentration of bacteria in the broth?
What will be an ideal response?
We want to determine the number of colony-forming units (cfu) per mL. Since 123 colonies are observed on the plate, this means that there were 123 bacterial cells (cfu) in 0.1 mL of the 100,000X dilution. Thus, in the original culture, there were 123 cfu × 100,000 (dilution factor) × 10 = 1.23 × 108 cfu/mL.
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Describe three molecular effects high pressure has on the physiology of organisms
What will be an ideal response?
When a cell nucleus from an adult organ (eg. heart, muscles) is inserted to another enucleated cell, it gives rise to a new replacement tissue for that organ. This procedure is known as
A) Embryo cloning B) Adult cloning C) Therapeutic cloning D) None of the above
Which of the following is not a good example of a housekeeping protein?
(a) DNA repair enzymes (b) histones (c) ATP synthase (d) hemoglobin
Which of the following are likely to predispose patients to fungal infections?
A) Cancer B) All of these choices are correct C) Malnutrition D) Tuberculosis E) AIDS