複選題

23. Which of the following describe an instance in which weak chemical bonds are useful in biological systems?
(A) The bonding of antibodies to the antigens they recognize
(B) Folding of proteins into their active conformation
(C) Stabilization of DNA double-stranded helices
(D) Formation of polypeptide chains through amide bond
(E) A gecko's ability to climb surfaces such as glass

複選題19.Select the CORRECT statements. (A) Epigenetic trait means the changes in DNA sequences. (B) Nucleosome is the DNA wrapped around eight histones (H2A, H2B, H3, H4) (C) Histone H3 can be methylated at serine. (D) Histone H3 can be acetylated at threonine. (E) An imbalance in the equilibrium of histone acetylation is associated with tumorigenesis and cancer progression.

複選題20. Select the FALSE statements. (A) Ligands bind to membrane receptors to activate downstream signaling. (B) Steroid hormone is a lipid-soluble molecule, and can cross the plasma membrane to reach nuclear receptor. (C) Her2/neu is a ligand and also an oncogene. (D) The mutated EGFR can constitutively activate the downstream signaling. (E) In case of Wnt signaling, beta-catenin phosphorylation is for survival.

21. Which of the following is NOT a component of a ribonucleotide? (A) Glucose (B) Ribose (C) Uracil (D) Thymine (E) Adenine

22. Which of the following modifications found on amino acids is also used to modify nucleic acids? (A) Phosphorylation (B) Glycosylation (C) Methylation (D) Acetylation (E) Hydroxylation

24. Which of the following is NOT a feature of the DNA helix proposed by Watson and Crick? (A) Double-stranded (B) Right-handed (C) Antiparallel (D) Complementary base pairing (E) Two grooves of equal dimensions

複選題25. Which of the following is a function of RNA? (A) Catalytic roles in translation and splicing (B) As transient carriers of genetic information. (C) As a carrier of amino acids to the site of protein synthesis. (D) Viral genomes having double-stranded RNA helices. (E) Targeting specificity in CRISPR-Cas9 genome-editing system

26. Why is green fluorescent protein (GFP) so useful in visualizing fusion proteins in eukaryotes? (A) The reaction is only dependent on the presence of GFP and one other cofactor. (B) It is easily cloned and expressed in eukaryotes. (C) The presence of just a few molecules of GFP fusion proteins can be sufficient for observing the proteins microscopically allowing the study of its location and movements in the cell. (D) It is derived from fire flies, which are easy to cultivate in the lab. (E) The GFP protein recognizes and binds to fusion proteins allowing the location of the fusion protein to be determined.

複選題27. Which of the following is correct regarding yeast three-hybrid analysis? (A) A useful tool in analyzing RNA-protein interactions (B) It contain a fusion protein of LexA, which binds the reporter construct, and MS2 which specifically binds an RNA tag that has been added to every RNA produced by the plasmid library. (C) It needs a plasmid library that contains random sequences from the genome tagged with a unique hairpin sequence that MS2 will bind. (D) It requires a reporter construct that contains a LexA operator (binding site) and a reporter gene. (E) It needs a fusion protein of the protein of interest and two tags - the calmodulin binding site and protein A.

28. Which of the following is a function of telomeres? (A) Serve as an attachment site for the proteins of the kinetochore. (B) They are sequences at the ends of the linear eukaryotic chromosome that protect the ends from proteases. (C) They are sequences of the eukaryotic chromosome that ensure proper distribution during mitosis. (D) In most eukaryotes, telomeres are protected from shortening by a protein-RNA complex called telomere terminal transferase. (E) Drosophila species maintain telomere lengths by the regulated insertion of retrotransposons into telomeres.

29. Which of the following is the function of histone H1? (A) Stabilizing nucleosomes (B) Promoting higher order chromosome structure (C) Modulating the repression of transcription by nucleosomes (D) Binding to regions undergoing active RNA synthesis (E) Mediating epigenetic regulation