27. Which of the following statements regarding stem cells (SCs) is correct?

(1) A stem cell can divide to one copy of itself and to one differentiated cell.

(2) The pluripotent SCs showed higher differentiation potency than the totipotent and multipotent SCs.

(3) Stem cells could be used to test new drug.
(A) (1)
(B) (2)
(C) (3)
(D) (1) and (3)
(E) (2) and (3)

複選題23. Translation defines the cellular proteome； which statement is correct? (A) Translational control has nothing to do with mRNAs. (B) The Cer4-Not complex affects mRNA translatability. (C) The elongation of translation is a uniform process. (D)Ribosome pausing increases translation efficiency. (E) The regulation of translation is independent of cell status and environment.

24.Consider the canonical nuclear localization sequence (cNLS) mediated protein transport mechanism； which statement is correct? (A) The cargo-carrier import complex is assembled in the nucleus. (B) The cargo protein utilizes its cNLS direct contact with the importinβ. (C) The RanGDP protein is more concentrated within the cytoplasm than the nucleus in preparation for cargo protein transport. (D) The RanGDP protein is essential to export the importin from the nucleus. (E) The cargo protein translocation is through the nuclear pore complex in the endoplasmic reticulum.

25. Vesicular transport describes vesicles bud off from one compartment and fuse with another. Most transport vesicles form from specialized, coated regions of membranes. They therefore bud off as coated vesicles. Which statement(s) is correct regarding coated vesicles?(1) Clathrin-coated vesicles mediate transport originating from the Golgi apparatus, endosome, and the plasma membrane. (2) COPI-coated vesicles contribute to the ER-to-Golgi transport, comprising large protein subcomplexes that are made of seven different protein subunits.(3) The retromer complex has been shown to mediate retrieval of various transmembrane receptors, such as the cation- independent mannose 6-phosphate receptor. (A) (3) only (B) (I) and (2) (C) (2) and (3) (D) (1) and (3) (E) All of above are correct.

26. Which of the following statement(s) is cotrect regarding to protein endocytosis or exocytosis? (1)Clathrin-mediated endocytosis involves cargo recognition and coat assembly, followed by membrane inv finally pinching off to deform membranes.(2) Proteins being internalized move to the lysosome and recycling endosome for protein degradation and reuse, respectively.(3) Neurotransmitters are typically released from synaptic vesicles into the synaptic clett via exocytosis, which is the fusion of vesicles with the plasma membrane. (A) (1) and (2) (B) (2) and (3) (C) (1) and (3) (D) (3) only (E) All of above are correct.

28. Which of the following statement regarding neurotransmitter is correct? (1) A neurotransmitter can be re-uptaken back to the presynaptic neuron. (2) Gamma aminobutyric acid (GABA) is the principal inhibitory neurotransmitter in the brain. (3) The role of a neurotransmitter agonist is to mimic or enhance the effects of specific neurotransmitters. (A) (1) and (2) (B) (1) and (3) (C) (2) and (3) (D) all of the above (E) none of the above

29. Which of the following statement about membrane potential and action potential propagation is NOT correct? (A) The resting membrane potential of animal neurons depend largely on non-gated K+ channels. (B) The resting potential of a typical neuron is -30 mV. (C) During an action potential, opening of voltage-gated Na+ channels happens first (D) Repolarization during the refractory period is largely due to opening of voltage-gated K+ channels. (E) All above are incorrect.

30. Which strategy is the current immune checkpoint blockade for cancer immunotherapy? (A) Anti-CTLA4 antibody (B) CAR-T therapy (C) Cancer vaccine (D) Bi-specific antibody (E) Antibody-dependent cytotoxicity

31. Re-replication during S phase results in DNA damage and genomic instability. Which one does NOT prevent the origin re-replication during DNA replication? (A) ORC, CDC6, CDT1, and MCM are the origin licensing factors. (B) Geminin directly binds to CDT1 to inhibit its licensing activity. (C) Dephosphorylation of pre-RC complex, MCM, ORC1, CDC6, and CDT1, represses reactivation of origins. (D) Cullin-based E3 ligases mediate the degradation of ORC1 and CDT1. (E) APC/C targets the degradation of CDC6 and CDT1

複選題32. Which one is responsible for DNA damage checkpoint? (A) APC/C E3 complex (B) Cul3-KLHL20 E3 ligase (C) Motor proteins (D) ATM kinase (E) ATR kinase

33. Which repair mechanism is primarily responsible for fixing thymine dimers caused by UV radiation? (A) Base excision repair (B) Mismatch repair (C) Nucleotide excision repair (D) Homologous recombination (E) Non-homologous end joining