30. Ribosomes attached to rough ER are the site for synthesis of many types of secretary proteins. Which of the following mechanism is typically used for nascent protein insertion into the mammalian ER membrane?
(A) Pretranslational.
(B) Cotranslational.
(C) Post-translational.
(D) Cotranscriptional.
(E) All of the above.

26. Which one of the following components is NOT necessary in an expression plasmid to be useful in the construction of recombinant DNA? (A) A multiple cloning site. (B) A tag coding sequence. (C) A promoter and a terminator. (D) Multiple cloning sites. (E) A coding sequence that is for antibiotic resistance.

27. Inheritance of phenotype sometimes does not directly involving the nucleotide is termed epigenetic inheritance. The epigenetic inheritance (A) only refers to genomic imprinting. (B) only effects female offspring. (C) only effects male offspring. (D) only refers to X inactivation. (E) can result in the expression of different alleles in different generations.

28. Which of the following is a possible application of tandem mass spectrometry? (A) Cell-specific gene expression. (B) Gene regulation. (C) Elucidation of metabolic pathways. (D) Tumor profiling. (E) Determination of the amino acid sequence of a peptide.

29. Which of the following is NOT correct regarding homeotic genes? (A) Homeotic genes encode transcription factors. (B) Homeotic genes are the only genes that contain the homeobox. (C) Homeotic genes are found in clusters called complexes. (D) The proteins encoded by homeotic genes contain DNA-binding domain. (E) Homeotic genes activate other developmental genes.

31. MPF is a cyclin-Cdk complex that was discovered first in Xenopus egg. Its activity fluctuates during cell cycle. Which of the following is NOT its characteristic? (A) Fluctuation of the cyclin concentration is the same as MPF activity. (B) The peak of the MPF activity is G2 phase. (C) The peak of the MPF activity is M phase. (D) The breakdown of the MPF occurs abruptly during M phase. (E) The activity of the MPF promotes mitosis by phosphorylating various proteins. .

32. Which of the following human DNA polymerases is responsible for replicating the mitochondrial DNA? (A) Alpha. (B) Beta. (C) Gamma. (D) Delta. (E) Theta.

33. Which one is the correct sequence of protein synthesis? 1. An aminoacyl-tRNA binds to the A site 2. A peptide bond forms between the new amino acid and a polypeptide chain 3. tRNA leves the P site, and the P site remains vacant 4. A small ribosomal subunit binds with Mrna 5. tRNA translocates to the P site(A) 5,4,3,2,1 (B) 2,4,5,1,3 (C) 4,1,2,5,3 (D) 4,1,3,2,5 (E) 1,3,2,4,5

34. Which one is correct for the description of transposons? (A) It occurs only in bacteria. (B) Some transposons do jump from one genome location to another, in what is called replicative transposition. (C) It plays little or no role in evolution. (D) Few can move to many alternative locations in the DNA. (E) None of the above.

35. Proto-oncogenes can change into oncogenes that cause cancer, which one can best explain the characteristic of proto-oncogenes? (A) p53 gene and ras gene belong to one of proto-oncogenes. (B) Pro-oncogenes are the normal cellular genes. (C) Cells produce proto-oncogenes as they age. (D) All of the above. (E) None of the above.

36. Which one of modifications is likely to alter the rate at which a DNA fragment moves through a gel during electrophoresis? (A) Altering the charges of the DNA fragment. (B) Increasing or decreasing the length of the DNA fragment. (C) Increasing the concentration of a gel. (D) Methylating the cytosine base within the DNA fragment. (E) All of the above.