Download 分子生物學小考(一) 範圍ch3~ch7

分子生物學小考(一)
範圍 ch3~ch7
單選題(每題 2 分, 總分 30 分)
1. RNA differs from DNA in that RNA
(A) contains ribose as its sugar
thymine
(B) all found only in the cytoplasm
(D)A and C are correct
(C) contains uracil instead of
(E) A, B, and C are correct
2. A particular triplet of bases in the coding sequence of DNA is AGT. The corresponding codon for the
mRNA transcribed is (A) AGT
(B) UCA
(C) TCA
(D) AGU
(E) ACU
3. Which of the following is correct about a codon?
(A) it catalyzes RNA synthesis
regions
(B) it consists of two nucleotides
(C) it consists of discrete amino acid
(D) it may code for the same amino acid as another codon
(E) all above are incorrect
4. The role of tRNA in gene expression is
(A) to house the codons that specify the amino acid sequence in a protein.
(B) to bring the amino acids into sequence within a protein.
(C) to carry the instructions for making a protein that are originally encoded in the DNA.
(D) all of the above
(E) none of the above
5. The enzyme involved in the elongation of mRNA during transcription is
(A) ligase
(B) RNA polymerase
(C) helicase
(D)transferase
(E) primase
6. In RNA processing after transcription, which segments of the mRNA transcript are removed?
(A) exons
(B) introns
(C) 5’-caps
(D) poly (A) tails
(E) methyl group
7. Which of the following lead(s) to a point mutation?
(A) deamination of a cytosine base into a uracil base
thymine base
(B) benzo(a)pyrene conversion of guanine to a
(C) deamination of 5-methyl cytosine into thymine
(D) all of the above
8. All of the following statements about mitochondrial DNA are true except
(A) All mammalian mitochondrial DNA contains introns.
(B) In mice, 99.99 percent of mitochondrial DNA is maternally inherited.
(C) Mitochondrial DNA encodes rRNAs and tRNAs.
(D) The human mitochondrial genome is smaller than the yeast mitochondrial genome.
(E) mitochondria contains several circular DNA
9. Most eukaryotic genes are controlled at the level of
(A) transcription initiation.
(B) transcription elongation.
(C) transcription termination.
(D)
translation initiation.
(E) translation termination.
10. Which of the following does not require protein enzymes?
(A) RNA editing
introns
(B) excision of group II introns
(C) trans-splicing
(D) excision of group III
(E) amino acid activation
11. If Hershey and Chase found S35 in progeny phages rather than P32, their experiment would have
demonstrated that (A) proteins contain phosphorus.
the host cell.
(D) phage protein enters the host cell.
(B) DNA contains sulfur.
(C) phage DNA enters
(E) None of the above.
12. In the Meselson and Stahl experiment, what percentage of the DNA is labeled with light nitrogen after
three generations of replication?
(A) 25%
(B) 50%
(C) 75%
(D) 100%
(E) None of the above.
13. Which of the following mammalian cell DNA polymerases is not correctly matched with its function?
(A) DNA Pol ε—DNA repair
(B) DNA Pol δ—ligation of DNA strands
(C) DNA Pol γ—elongation of both strands
(D) DNA Pol β—DNA repair
(E) DNA Pol α—priming DNA synthesis
14. Which of the following is the best definition of translation?
(A) a process by which pre-mRNA is transformed into mature mRNA
(B) the process by which pre-mRNA is translated by ribozymes to produce proteins
(C) a process by which a gene is converted into mRNA
(D) a process by which a gene is converted into a protein
(E) the process by which ribosomes read the genetic message to produce a protein
15. RNA molecules that exhibit catalytic activity are called
(A) microRNAs
(B) ribonucleases
(C) ribosomes
(D) ribozymes
(E) ribonucleotides