The Restriction Enzymes of Bacteria Protect the Bacteria from Successful

question 23

Multiple Choice

The restriction enzymes of bacteria protect the bacteria from successful attack by bacteriophages, whose genomes can be degraded by the restriction enzymes. The bacterial genomes are not vulnerable to these restriction enzymes because bacterial DNA is methylated. This situation selects for bacteriophages whose genomes are also methylated. As new strains of resistant bacteriophages become more prevalent, this in turn selects for bacteria whose genomes are not methylated and whose restriction enzymes instead degrade methylated DNA. Over the course of evolutionary time, what should occur?

• A) Methylated DNA should become fixed in the gene pools of bacterial species.
• B) Nonmethylated DNA should become fixed in the gene pools of bacteriophages.
• C) Methylated DNA should become fixed in the gene pools of bacteriophages.
• D) Methylated and nonmethylated strains should be maintained among both bacteria and bacteriophages, with ratios that vary over time.
• E) Both the first and second responses are correct.

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Definitions:

Short-Term Assets

Assets expected to be converted into cash, sold, or consumed within one year or the operating cycle, whichever is longer.

Aggressive Working Capital Policy

A strategy emphasizing minimal cash and inventory levels and maximizing short-term liabilities to fund operations and investments.

Permanent Working Capital

Permanent Working Capital is the minimum amount of capital that a company needs to operate effectively and continuously over the long term.

Financing Current Assets

The process of obtaining funds to cover short-term operational needs such as inventory, accounts receivable, and day-to-day expenses.