30. Which peptide has greater absorbance at 280 nm ?
(A) Ser-Val-Trp-Asp-Phe-Gly-Tyr-Trp-Ala
(B) Gin-Leu-Glu-Phe-Thr-Leu-Asp-Gly-Tyr
(C) Asp-Tle-Asn-Pro-Thr-Arg-Asp-Val-Phe
(D) Asn-Phe-Gln-Met-Thr-Leu-Tyr-Lys-Tyr

23. Which of the following description purine and pyrimidine de novo synthesis INCORRECT? (A) The initial reaction of purine biosynthesis is forming phosphoribosyl pyrophosphate (PRPP). (B) Both adenosine monophosphate (AMP) and guanosine monophosphate (GMP) can be derived from inosine monophosphate (IMP). (C) The so-called orotate pathway of pyrimidine de novo synthesis involves using PRPP serves as a scaffold for the subsequent assembly of the pyrimidine ring to form uridine 5'-monophosphate (UMP). (D) Thymidylate synthase is the sole enzyme responsible for de novo biosynthesis of thymidine monophosphate (TMP). (E) Cross-regulation exists between purine and pyrimidine biosynthesis, suggesting coordinated control of their biosynthesis.

24. Which of the following nucleotide serves as a key second messenger in signaling pathway? (A)(B)(C)(D)(E)

25. Which of the following is a nucleotide, which is composed of a nitrogenous base, a pentose sugar and a phosphate? (A) Adenine (B) Guanylate (C) Thymidine (D) Deoxycytidine

26. In each of the following pairs of amino acids, identify which amino acid would be most soluble in water: (A) Glu, Ile (B) Tyr, Phe (C) Ser, Ala (D) Trp, His

1.Identify the components that is/are NOT a part of DNA. (A) Ribose (B) Base A, T, C, G (C) 5'-phosphate group (D) 3'-hydroxyl group (E) Deoxyribose

2.DNA is a structurally dynamic molecule that can exist in a variety of helical forms. Which of the following is/are NOT a known DNA structure? (A) A-DNA (B) B-DNA (C) , C-DNA (D) X-DNA (E) Z-DNA

複選題3. Which of the following enzymes is/are required for DNA replication? (A) Helicase (B) Topoisomerase (C) DNA polymerase (D) DNA ligase (E) Recombinase

複選題4.Which of the following statements about DNA replication is/are CORRECT? (A) 3' to 5' polymerase activity is used to synthesize both strands of DNA (B) DNA replication is semiconservative. (C) DNA polymerase needs a template and a RNA primer to initiate DNA synthesis. (D) Helicase is required to solve the supercoiled structure formed during DNA replication. (E) The 5' to 3' exonuclease proof-reading activity is required maintain the fidelity of DNA replication.

5. The 5' End is potentially lost during replication of linear eukaryotic chromosomal DNA. Which molecules or structures is/are required to prevent the shortening of the 5' end of DNA? (A) DNA gyrase (B) Telomere (C) Telomerase (D) DNA polymerase (E) Helicase

複選題6. Which physical or chemical factors in the following list can cause DNA mutation? (A) Heat (B) Ultra-violet light (C) Acridine (D) Nitrous acid (E) 5-Bromouracil