Multiple Choice, 2 pts each:

1. Down syndrome is usually the result of
   1. trisomy 21. (YOU BET!)
   2. a missing X chromosome. (incorrect)
   3. a missing Y chromosome. (incorrect)
   4. an extra X chromosome. (incorrect)
   5. an extra Y chromosome. (incorrect)
      Hint
2. If a female carrier mates with a male who has an X-linked disorder, what is the probability of a son having the disorder?
   1. 0% (incorrect)
   2. 25% (incorrect)
   3. 50% (K!)
   4. 75% (incorrect)
   5. 100% (incorrect)
      Hint
3. DNA synthesis occurs in the
   1. 5' to 3' direction on the lagging strand. (OBVIOUSLY!)
   2. 3' to 5' direction on the leading strand. (incorrect)
   3. 3' to 5' direction on the lagging strand. (incorrect)
   4. 1' to 5' direction on the lagging strand. (incorrect)
   5. 1' to 5' direction on the leading strand. (incorrect)
      Hint
4. Synthesis of a new DNA strand usually begins with
   1. an RNA primer. (SWEET!)
   2. a DNA primer. (incorrect)
   3. an Okazaki fragment. (incorrect)
   4. DNA ligase. (incorrect)
   5. a thymine dimer. (incorrect)
      Hint

Fill In, 2 pts each:

5. DNA polymerization occurs in segments called Okazaki fragments on the                     strand.
   Hint