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Which of the following describes the approximate chromosomal location of the termination of...

Question:

Which of the following describes the approximate chromosomal location of the termination of replication in bacteria?

a. Termination occurs at oriC once the replication fork has advanced the entire length of the chromosome.

b. Termination occurs at a location one-quarter around the chromosome.

c. Termination occurs at a location halfway around the chromosome.

d. Termination occurs at random locations where replication forks collide.

e. Termination occurs at the first Ter site encountered by the replication fork.

Bacterial Chromosome Structure:

A bacterial cell typically has one double-stranded circular chromosome, although it may exist in multiple copies in a single cell. DNA replication begins at the origin, a DNA sequence called oriC. Then, DNA replication is bidirectional, with two replication forks forming and moving in both directions away from the origin around the chromosome. Both parental DNA strands of the chromosome are used as template to synthesize complementary DNA strands.

Answer and Explanation: 1

The statement that best describes the approximate chromosomal location of the termination of replication in bacteria is that

c. Termination occurs at a location halfway around the chromosome.

  • Because DNA replication of a circular bacterial chromosome is bidirectional from oriC, the two replication forks meet approximately 180 degrees, or halfway around the circular chromosome.

Choice a. is incorrect because termination of replication does not proceed around the entire length of the chromosome. Because DNA replication is bidirectional, termination occurs halfway around the chromosome where the two replication forks meet.

Choice b. is incorrect because termination of replication occurs halfway, not one-quarter of the way, around the circular chromosome.

Choice d. is incorrect because termination of replication does not happen at random locations around the chromosome. Rather, it occurs halfway around the chromosome because that is where replication forks collide.

Choice e. is incorrect because termination does not occur at the first Ter site encountered by the replication form. Rather, it a bacterial chromosome has multiple Ter sites in each direction to ensure termination of replication.


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Bacterial Chromosome: Definition & Structure

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Chapter 18 / Lesson 20
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Learn about the bacterial chromosome and compare the bacterial chromosome function to the human chromosome. Understand the bacterial chromosome structure.


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