34. HOW MANY of the following techniques can be used to detect mRNAs?
a. Northern blotting b. In situ hybridization c. Real-time PCR d. Sanger sequencing
(A) 1
(B) 2
(C) 3
(D) 4

30. Which one described below is true for post-translational modification (PTM) of proteins?(A) Phosphorylation but not dephosphorylation plays an important role in signal transduction.(B) The activity of histone can be regulated by methylation but not acetylation at its lysine residue.(C) The conformation and also biological activity of protein can be regulated by PTM.(D) Ubiquitination would decrease the molecular weight (size) of protein.

31. Which one of the following statements is true for protein misfolding?(A) May increase the protein stability(B) May reduce the water solubility of protein.(C) Would easily aggregate in the cytoplasm.(D) All of the above.

32. Which of the following is true of the lagging strand during DNA replication?(A) It is made in the same direction as the replication fork in opening.(B) It contains Okazaki fragments.(C) It is made much more slowly than the leading strand.(D) It is made in the 3' to 5' direction.

33. Which of the following statements about epigenetic modifications are correct?a. Epigenetic modifications are not influenced by underlying DNA sequenceb. Epigenetic modifications are stable over timec. X-chromosome inactivation occurs in female mammal onlyd. DNA methylation always negatively correlated with gene expression on the promoter regions of a gene.e. Epigenetic modifications can be influenced by the environmental factors, such as nutrition.(A) a, b, d, e(B) e only(C) a, b, c, d, e(D) a, d, e

35. Which of the following statement is wrong about alternative splicing? (A) Alternative splicing is a process that exons of a gene are differentially joined or skipped (B) Multiple protein isoforms can be encoded by a single gene during the process (C) The process can produce two or more proteins that differ in their function (D) The alternatively splicing events are often differentially regulated among individuals and populations, but not across tissues

36. Which buffer molecule does NOT carry a positive charge?(A) Tris(B) phosphate(C) imidazole(D) none of the above

37. Which of the following enzymes is NOT responsible for assimilation of ammonia?(A) glutamine amidotransferase(B) glutamate dehydrogenase(C) glutamate synthase(D) carbamoyl phosphate synthetase

38. Which symptom is a consequence of vitamin B12 deficiency?(A) anemia(B) homocysteinemia(C) neurological disorder(D) all of the above

39. Which enzyme is defective in patients with maple syrup urine disease?(A) branched-chain a-amino acid aminotransferase(B) branched-chain a-amino acid dehydrogenase(C) branched-chain a-keto acid dehydrogenase(D) branched-chain a-keto acid decarboxylase

40. 2',3'-dideoxycytidine (ddC), can serve as a drug for HIV infections because of the absence of a_____group which is required for______.(A) 2'-hydroxyl; transcription(B) 3'-hydroxyl; replicative chain elongation(C) 5'-hydroxyl; translation(D) 2'-hydroxyl; replicative chain elongation