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1.A bacterial operon contains all of the following features except:

a. multiple transcription start sites
b. multiple cistrons
c. multiple ribosome binding sites
d. multiple genes encoding enzymes involved in a related function

2. Which of the following types of DNA will reanneal at the fastest rate?

a. single copy DNA
b. moderately repeated DNA interspersed throughout the genome
c. short sequences repeated in tandem arrays
d. mobile DNA elements

3. Which of the following statements about minisatellite DNA is true?

a. it is present at only a single site in the genome
b. it consists of repeating units of 15 to 100 basepairs
c. it exists in tandem arrays approximately 100 kilobases in length
d. it is located on extrachromosomal DNA molecules

4. All of the following statements about transposons are true except:

a. they move via RNA intermediates
b. they include DNA that encodes transposase
c. they often contain a drug resistance gene
d. they contain insertion sequences

5. All of the following steps are performed by the enzyme transposase during nonreplicative transposition of bacterial insertion sequences except:

a. excision of the IS element from the donor DNA molecule
b. introduction of staggered cuts into the target DNA molecule
c. ligation of the IS element to the target DNA
d. synthesis of DNA to fill in the single stranded gaps

6. Describe the difference between a pseudogene and a processed pseudogene.

7. (2 pts) What characteristics of a DNA sequence would suggest that it is a transposon? How could you distinguish a transposon from an IS element?

8. (2 pts) How could you determine whether a newly-described mobile genetic element was a transposon or a retrotransposon? Describe an experiment that could address this question. Include the results you would expect to obtain in each case.

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