11. What are genes?

A. The functional unit of inheritance
B. A fragment of DNA
C. A portion of a chromosome
D. All of the above

12. Which of the following is not a transcription factor?

A. Helix-turn-helix proteins
B. Zinc finger proteins
C. Leucine zipper proteins
D. Steroid hormones

13. Sex determination in Drosophila involves

A. alternate splicing
B. methylation
C. gene amplification
D. none of these

14. Enhancers differ from promoters in that

A. they initiate transcription
B. they are adjacent to the start codon
C. their orientation can be inverted without effect
D. they are restricted to a specific gene

15. Methylated gene are

A. active
B. silent
C. dynamic
D. either (a) or (b)