複選題
24.Which of the following is/are included in the universal features of DNA replication?
(A) Release of PPi from a nucleoside triphosphate.
(B) Synthesis from the 5' end to the 3' end.
(C) Base pairing of A to U and G to C.
(D) Use of a primer.
(E) None of the above.

20.Which of the following events occurs in prokaryotes but not in eukaryotes? (A)Post-transcriptional splicing (B) Translation in the absence of a ribosome (C) Concurrent transcription and translation (D) Post-translational modification (E) Alanine can be added to polypeptide chain by tRNA with different codon.

21.A class of mutations that results in multiple contiguous (side-by-side) amino acid changes in proteins is/are probably caused by which the following types of mutations? (A) recombinant (B) base analog (C) transversion (D) frameshift (E) transition

複選題22. Which of the following is/are functional elements of a plasmid? (A) centromere (B) drug-resistance gene (C) polylinker sequence (D) origin of replication (E) autonomously replicating sequence

複選題23. Unlike bacterial mRNA, eukaryotic mRNA must undergo______before it may be used for translation. (A) folding mRNA into hairpin loops (B) export to the cytoplasm (C) capping (D) splicing (E) polyadenylation

25. 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) CRISP/cas9. (E) site-directed mutagenesis.

複選題26.Which of the following statements is/are TRUE? (A) Protein synthesis in prokaryotes always starts with a methionine residue. (B) A Shine-Dalgarno Sequence is a sequence of nucleotides in an mRNA that interacts with the small subunit of a ribosome to begin translation. (C) In bacteria, translation of the mRNA begins during the synthesis of the mRNA. (D) A polysome is a polypeptide chain in the process of being formed. (E) The ribosome is actually a ribozyme.

複選題27. Intracellular second messengers include all of the following? (A) Ca2+. (B) diacylglycerol (DAG). (C) cATP. (D) nitric oxide (NO). (E) cGMP

複選題28. Which of the following statements is/are TRUE? (A) A nucleosome contains 6 histones within its core. (B) Chromatin is composed of DNA and protein. (C) Nucleosomes are composed of about 100 bp of DNA wrapped around a histone core. (D) DNA methylation is the only known natural modification of DNA. It affects cytosine bases. (E) Histones have highly conserved sequences among eukaryotes.

複選題29. Which of the following residues can be phosphorylated by protein kinases? (A) Serine (B) Lysine (C) Threonine (D) Tyrosine (E) Alanine.

複選題30.Which of the following statements is/are TRUE of supercoiling? (A) The relaxed form of DNA is more stable and is therefore the preferred form in the cell. (B) Most organisms maintain their DNA in a slightly overwound state in order to enhance strand separation during transcription and replication. (C) Overwound DNA is in the B form so relaxed DNA has less turns than B-form DNA. (D) Most organisms maintain their DNA in a slightly underwound state in order to compact their DNA. (E) The relaxed form of DNA can only be maintained if the DNA is a closed circle.