Download Answers to Biological Inquiry Questions – Brooker et al ARIS site

Answers to Biological Inquiry Questions – Brooker et al ARIS site
Chapter 18
Figure 18.5
BIOLOGICAL INQUIRY QUESTION: Let's suppose a bacterial strain divides every 30 minutes. If a
single cell is placed on a plate, how many cells will be in the colony after 16 hours?
ANSWER: 16 hours is the same as 32 doublings. So, 232 = 4,294,967,296. (The actual number
would be much less because the cells would deplete the growth media, and grow more slowly than
the maximal rate).
Figure 18.8
BIOLOGICAL INQUIRY QUESTION: Would the results have been different if the pore size was
larger and allowed the passage of bacterial cells?
ANSWER: Yes. The two strains would have mixed together, allowing them to conjugate. Therefore,
there would have been colonies on the plates.
Figure 18.15
BIOLOGICAL INQUIRY QUESTION: From the perspective of the virus, what are the primary
advantages of the lytic and lysogenic cycles?
ANSWER: The advantage of the lytic cycle is that the virus can make many copies of itself and
proliferate. However, sometimes the growth conditions may not be favorable to make new viruses.
The advantage of the lysogenic cycle is that the virus can remain latent until conditions become
favorable to make new viruses.
Figure 18.20
BIOLOGICAL INQUIRY QUESTION: Researchers are trying to discover drugs that prevent prion
diseases. What are possible effects of a drug that would prevent the spread of the disease?
ANSWER: There is more than one possibility. A drug could specifically recognize the PrPSc
conformation and prevent it from binding to PrPC. It could convert PrPSc back to PrPC. It could
recognize PrPC and prevent the binding of PrPSc. It could bind to PrPC and stabilize its
conformation, thereby preventing PrPSc from changing it to the abnormal conformation. You may
also think of other interesting possibilities.