In Ecoli,the Adenine in the Sequence GATC Is Methylated by the the Dam

question 65

Multiple Choice

In E.coli,the adenine in the sequence GATC is methylated by the Dam enzyme.In the same cells a restriction endonuclease recognizes and cleaves dsDNA with GATC on either strand.Why does E.coli have these two enzymes?

• A) The enzymes cut the E. coli genome into pieces that bind to viral particles and inhibit viral replication.
• B) The enzymes increase the rate of mutation and genome rearrangement, thus increasing the likelihood that E. coli cells will mutate and become resistant to viral infection.
• C) The enzymes encourage lysogeny because the cleavage sites are recognized by viral integrases.
• D) The enzymes protect E. coli from infection by preferentially degrading viral or other exogenous DNA that is not methylated.

---

Definitions:

Personal Freedom

The rights and liberties that allow individuals to act freely without undue restraint or interference from government or other individuals.

Prohibition

The period from 1920 to 1933 in the United States when the manufacture, sale, and transportation of alcoholic beverages were banned by constitutional amendment.

Equal Rights Amendment

A proposed amendment to the U.S. Constitution aiming to guarantee equal legal rights for all American citizens regardless of sex, which has not been ratified.