29. Which of the following statements regarding stem cells is incotrect? 

(1) Endoderm and ectodern cells are pluripotent stem cells.

(2) Cord blood stem cells are multipotent stem cells.

(3) Lymphoid progenitors are oligopotent stem cells.
(A) 1 only
(B) 2 only
(C) 3 only
(D) 1 and 3
(E) 2 and 3

25. Which of the following statement(s) is correct regarding to intracellular protein trafficking?(1) Vesicular transport is tightly regulated by small GTPase that cycles between GDP-bound and GTP-bound state.(2) COPII vesicles transport proteins from ER to Golgi while COPI vesicles transport proteins from Golgi to the plasma membrane.(3) Membrane fusion step is driven by GTP hydrolysis for the dissociation of SNARE protein complexes. (A) 1 only (B) 1 and 2 (C) 1 and 3 (D) 2 and 3 (E) All of above are correct.

26. Which of the following statement(s) is corect regarding to protein endocytosis or exocytosis?(1) Clathrin forms the triskelion structure for the polymerization of a polygonal lattice.(2) The acidic pH of endosomes causes receptor-ligand complexes to dissociate. The best example to describe the phenomenon is the endocytosis of transferrin receptor.(3) Transmission of nerve impulses at chemical synapses depends on the exocytosis of neurotransmitter-filled synaptic vesicles. (A) I and 2 (B) 2 and 3 (C) 1 and 3 (D) 3 only (E) All of above are correct.

27. Which of the following statements regarding G protein or G protein-mediated signal transduction is incotrect?(1) Epinephrine binding to the beta-adrenergic receptor causes an activation of adenylyI cyclase through the activation of a stimulatory G protein.(2) Gi alpha submit of the trimeric G proteins can inhibit adenylyl cyclase(3) Gq alpha submit of the trimeric G proteins can stimulate Pl-phospholipase C (A) I and 2 (B) I and 3 (C) 2 and 3 (D) all of the above. (E) none of the above.

28. Which of the following statement about membrane potential and action potential propagation is correct?(1) The resting potential of a typical neuron is -30 my.(2) The resting membrane potential of animal neurons depend largely on nongated K+ channels.(3) During an action potential, opening of voltage-gated Cazt channels happens first.(4) Repolarization during the refractory period is largely due to opening of voltage-gated K+ channels. (A) I and 3 (B) 2 and 4 (C) 1,2 and 4 (D) 1, 3 and 4 (E) 2. 3 and 4

30. Which method is NOT for detecting dead cells? (A) Trypan blue (B) Annexin V (C) Ki67 (D) Comet assay (E) Cleaved caspase-3

31. Which method can determine cells at the S phase? (A) PARP1 immunoblotting (B) Cyclin D immunoblotting (C) CFSE staining (D) BrdU incorporation (E) Cohesion cleavage

32. What kind of treatment does anti-PD1 or anti-PDL1 antibody work for cancer immunotherapy? (A) mRNA vaccine (B) Immune checkpoint blockade (C) CAR-T cell therapy (D) Precision medicine (E) autoimmunity

33. Which of the following repair pathway is mainly a response for repairing DNA double-stranded breaks? (A) base excision repair (B) nucleotide excision repair (C) mismatch repair (D) homologous recombination repair (E) proofreading polymerases

34. In the large-scale production of a particular human protein in insect cells, the cDNA corresponding to the protein was modified so that the expressed protein would have six histidine residues at the C-terminus. The purpose of this modification was to (A) facilitate transfer of the cDNA into the insect cells. (B) provide a promoter for the transcription of the cDNA in insect cells. (C) facilitate purification of the expressed protein though binding to an affinity column containing chelated nickel atoms. (D) prevent degradation of the expressed protein by insect cell proteases. (E) provide the protein solubility

35. What method can be used to functionally inactivate a gene without altering its sequence? (A) gene knockout (B) RNA interference (C) dominant negative mutation (D) CRISPR-Cas9 genome editing (E) only B and C