25. The first three bases of the 6-base recognition cleavage site of HindIII, a palindromic restriction enzyme, are AAG. What is the complete sequence of this 6 bp site?
(A) AAGAAG.
(B) AAGCTT.
(C) AAGGAA.
(D) AAGCUU.

21. What is   NOT   true about Sanger sequencing? (A) It was developed by Frederick Sanger and colleagues in 1977. (B) The most widely used sequencing method for approximately 40 years. (C) A method based on in vitro DNA digestion. (D) Incorporation of chain-terminating dideoxynucleotides.

22. What is an "Okazaki fragment"? (A) The strand of nascent DNA which is synthesized in the same direction as the growing replication fork. (B) A short single-stranded nucleic acid utilized by all living organisms in the initiation of DNA synthesis. (C) Short sequences of DNA nucleotides which are synthesized discontinuously and later linked together by the enzyme DNA ligase to create the lagging strand during DNA replication. (D) A particular sequence in a genome at which replication is initiated.

23 The following DNA sequence is a region of a human genome that expresses a protein. If you want to down regulate the gene expression of this protein by making a 30 bp deletion in DNA, which position would be the most appropriate? (A) B. (B) C. (C) E. (D) All of the above. 

24. Following the figure in questions 3, if you want to truncate this protein by making a point mutation in DNA, which position would be the most appropriate? (A) B. (B) C. (C) E. (D) All of the above.

26. Plasmids used in recombinant DNA technology typically (A) possess a gene for antibiotic resistance. (B) replicate independently of the host genome. (C) are circular double stranded molecules. (D) All of the above.

27. What is the advantage of adding SDS to gel electrophoresis? (A) SDS colors the proteins for visualization. (B) SDS reduces disulfide bonds. (C) SDS allows proteins to be separated on the basis of approximate mass. (D) None of the above.

28. For identification of a gene using Southern blot analysis, against which strand of DNA must the probe complement? (A) either the top or bottom strand. (B) only the coding strand. (C) only the template strand. (D) None of the above.

29. Which of the following affect(s) the sedimentation of a particle? (A) mass. (B) shape. (C) the density of the solution. (D) All of the above.

30. "Footprinting" or DNase protection is a technique used to identify (A) a region of DNA that has been damaged by mutation. (B) E. coli cells that contain a desired, cloned piece of DNA. (C) the position of a particular gene of a chromosome. (D) the specific binding site of a repressor, polymerase, or other protein on the DNA.

1. Characteristic of simple epithelium is that they (A) are arranged indiscriminately (B) continue to divide and help in organ function (C) Make a definite layer (D) None of above