You Have Found a Strain of Escherichia Coli That Has

question 49

Multiple Choice

You have found a strain of Escherichia coli that has an unusually short doubling time of only 15 minutes, despite the fact that its complete DNA replication should take almost 35 minutes. You also find that there is only one replication origin on its chromosome from which two forks originate, just like the normal process described for E. coli. However, you discover that the origin of replication in this strain has a significantly shorter "refractory period," resulting in the reactivation of the origin before the previous round of replication is over. Based on this model, if you examine the chromosomes of this strain (under conditions of fast growth) , how many replication forks would you expect to observe per chromosome on average?

• A) Two, just like the wild-type strain
• B) Four
• C) Six
• D) Eight
• E) Ten

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Definitions:

M/M/1 Queue

A model describing a queueing scenario with a single server, where arrivals are determined by a Poisson process, and service times have an exponential distribution.

Units in the System

The total number of items or entities currently being processed or within a particular process or system at any given time.

Poisson Distribution

A statistical distribution describing the probability of a given number of events happening in a fixed interval of time or space, assuming events happen independently at a constant rate.

Exponential Distribution

A probability distribution that describes the time between events in a Poisson process, showing how a process is spread out over time.