1. What are dideoxynucleoside triphosphates, and what is their purpose?
2. For the three steps of a Polymerase Chain Reaction, indicate the temperature of each step, and what happens during that step.
i)
ii)
iii)
3. Alchemase is an enzyme found in some geese that converts lead into gold.
This is a restriction map of the goose alchemase gene:

The SalI restriction site in the box is polymorphic. Geese with a functional alchemase gene secrete gold into the egg white when they are fed a diet rich in lead. A functional alchemase gene, ALC+ (which is dominant to a mutation that inactivates the gene) has that SalI site. Most geese have a mutation that inactivates the alchemase gene (alc-), and that mutation also eliminates the SalI site. These geese do not lay golden eggs, and will die if fed large amounts of lead. Someone tries to convince you to buy a goose that supposedly lays golden eggs, but before buying it you manage to get a DNA sample from the goose. After digesting the goose's DNA with SalI, you run it on a gel and blot it. You have PCR primers that will amplify the region of DNA identified in the figure. You radioactively label this PCR product and use it as a probe of your Southern blot. What result(s) would you see on the blot in these three cases:
a) the goose is an alchemase mutant, and you should not buy it.
b) the goose is heterozygous for alchemase, and you should buy it.
c) the goose is homozygous for a functional alchemase gene, and you should buy it.