28. The molecular weight of protein or peptide can be determined by__________.
(A) Isoelectric focusing electrophoresis (IEF)
(B) Ion-exchange liquid chromatography
(C) Mass spectrometry
(D) Circular dichroism (CD)

24. What material plays a role of radical initiator in formation of sodium dodecyl sulfate (SDS) polyacrylamide gel? (A) Ammonium persulfate (B) Tetramethylethylenediamine (C) SDS (D) Acrylamide

25. Which of the following method can NOT be used to study the sequence of monosaccharides, position and configuration of glycosidic bonds? (A) Hydrolysis with strong acid (B) Enzymatic hydrolysis with specific glycosidases (C) NMR (D) mass spectrometry

26. Which method is NOT the common way to denature a protein?(A) by miscible organic solvents(B) by extremes of pH environments(C) by urea(D) by filtration

27. The information needed for the structure of a protein is determined by__________.(A) Amino acid composition(B) Primary structure(C) Secondary structure(D) Tertiary structure

29. Which one described below is NOT true for protein structure?(A) Hydrogen bonds are most important in secondary structure of protein.(B) Reverse turn is often found connecting the strands of an antiparallel ẞ-sheet.(C) The overall folding of a single protein subunit is called quaternary structure.(D) A domain is a folded region of protein, often shared by proteins and has specific biological function.

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

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