18. The first group of researchers to correctly identify the double-helix structure of DNA were _____
(A) McClintock and Franklin
(B) Hershey and Chase
(C)Pauling and Avery
(D) Watson and Crick

14. Gene duplications, such as the ultra bar-eye phenotype of Drosophila, may be caused by which of the following? (A) the crossing over of misaligned chromosomes (B) deletion of important genetic information (C)reciprocal translocations (D) position effect

15. The production of gene families, such as the globin genes, is the result of _____(A) inversions (B) deficiencies (C)gene duplications (D) simple translocations

16. Given the following sequence of genes on a chromosome, determine what change in chromosome structure occurred. (the * indicates the centromere) (A) reciprocal translocation (B) pericentric inversion (C)paracentric inversion (D) gene duplication

17. According to Chargaff's rule, if the DNA of a species contains 20% adenine, what percent of guanine will it contain? (A) 20% (B) 30% (C)50% (D) 75%

19. You have discovered a strain of E. coli that grows very slowly-the generation time is nearly 12 hours compared to the normal 20-30 minutes. Upon further investigation, you find a mutation in the DNA polymerase III gene. What subunit of the holoenzyme, does this mutation affect the most. (A) α (B) β (C)γ (D) ψ

20. Okazaki fragments do which of the following? (A) assist in forming the replication fork (B) bind to the oriC region (C)assist in the synthesis of DNA from the lagging strand (D) reform the double-helix following replication

21. Which of the following is an example of a processive enzyme? (A) DNA polymerase I (B) DNA polymerase III (C)DNA ligase (D) Okazaki fragments

22. Most eukaryotic genes are collinear. (A) True (B) False (C)Because they are driven by a promoter (D) B and C are right

23. An R loop experiment was performed on two different mRNA's. The first showed one R loop, while the second showed two R loops separated by a region of double-stranded DNA. What is the composition of these two mRNA's? (A) The first contains no introns and the second two introns (B) The first contains no introns and the second one intron (C)The first contains one intron and the second two introns (D) The first contains two introns and the second one intron

24. What enables the splicing of group I and II introns? (A) spliceosomes (B) ribozymes (C)snRNA (D) poly-A tail