A composite transposon integrated in a circular plasmid occasionally transposes the DNA comprising the original plasmid rather than the transposon’s central region. Explain how this is possible.

The E. coli genome contains 1009 Chi sequences. Do these sequences occur at random, and, if not, how much more or less frequently than random do they occur?

A replication fork encountering a single-strand lesion may either dissociate or leave a single-strand gap. The latter process is more likely to occur during lagging strand synthesis than during leading strand synthesis. Explain.

Why is the methylation of DNA to form $O^6$-methylguanine mutagenic?

What is the half-life of a particular purine base in the human genome assuming that it is subject only to spontaneous depurination? What fraction of the purine bases in a human genome will have depurinated in the course of a single generation (assume 25 years)? The DNAs of $\sim 4000$-year-old Egyptian mummies have been sequenced. Assuming that mummification did not slow the rate of DNA depurination, what fraction of the purine bases originally present in the mummy would still be intact today.

Explain how certain mutant varieties of Pol I can be nearly devoid of DNA polymerase activity but retain almost normal levels of $5^{\prime} \rightarrow 3^{\prime}$ exonuclease activity.

A box contains N identical gas molecules equally divided between its two halves. Does the time spent in the central configuration increase or decrease with an increase in N?

For following, write the Lewis structure(s), predict the molecular structure (including bond angles), and give the expected hybridization of the central atom.

$$\mathrm{O}_3$$

Using cylindrical coordinates, prove that the centroid of a right circular cone of height h and radius R is located at height

$$\frac { h } { 4 }$$

on the central axis.

The weights of the fish caught by a fisherman were in pounds:

$$1.7,1.8,3.0,1.8,3.5,3.1,3.3$$

Which measure of central tendency would the fisherman use to represent his fishing most favorably?

Work each problem.

Find the radius of a circle in which a central angle of $\dfrac{\pi}{6}$ radian determines a sector of area $64 \mathrm{~m}^2$.

What shape do you expect for a molecule with a central atom and the following pairings? Two bonding pairs of electrons and two non-bonding pairs of electrons

For following, write the Lewis structure(s), predict the molecular structure (including bond angles), and give the expected hybridization of the central atom.

$$\mathrm{SeBr}_4$$