4. The Ds transposable element of maize cannot transpose on its own because it lacks
(A) origin of replication.
(B) inverted repeats.
(C) transposase.
(D) antibiotic resistance.
(E) Tn10.

120. ( A )漫步在 / ( B )斜風細雨中 / ( C )僅有 / ( D )一番情趣

1. Which of the following statements is true concerning DNA replication inprokaryotes?(A) DNA replication is conservative.(B) DNA replication is discontinuous.(C) DNA replication is RNA dependent.(D) DNA replication requires only one enzyme.(E) There are two origins of replication.

2. Which of the following mammalian cell DNA polymerases is NOT correctlymatched with its function?(A) DNA Pol a-priming DNA synthesis(B) DNA Pol ẞ-DNA repair(C) DNA Pol y elongation of both strands(D) DNA Pol &-ligation of DNA strands(E) DNA Pol ɛ-DNA repair

3. West and colleagues used gel mobility shift assays to demonstrate that________could bind to and resolve Holliday junctions.(A) RecA(B) RecB(C) RuvA(D) RuvB(E) RuvC

5, Which of the following transposons does not contain inverted repeats or LTRs at its ends? (A) Tn3 (B) Ds (C) copia (D) Ty (E) Alu elements

6. Sarah has performed a chromatin immunoprecipitation experiment using a specific antibody that recognizes a specific protein that can bind to TATA box in E. coli. This protein is likely (A) TFIID (B) RNA polymerase-II (C) Sigma factor (D) TBP (E) Helicase

7. Which of the following mechanism is most used to repair a single stranded DNA break? (A) Mismatch repair (B) Homologous recombination (C) Nucleotide excision repair (D) Base excision repair (E) Non-homologous end joining

8. Which modified nucleotide base is part of the 5'cap on eukaryotic mRNAs?(A) cytosine(B) guanine(C) adenine(D) uracil(E) thymidine

9. Which of the following limits the use of PCR to detect and isolate genes? (A) The sequence at the beginning and end of the DNA to be amplified must be known. (B) It also produces large numbers of copies of sequences beyond the 5' or 3' end of the desired sequence. (C) It cannot be used to amplify cDNAs or mRNAs. (D) It will amplify only sequences present in multiple copies in the DNA sample. (E) Quantitation can be applied by adding modified fluorescent nucleotides.

10. Unlike DNA, which typically forms a helical structure, different molecules of RNA can fold into a variety of three-dimensional shapes. This is largely because_________. (A) RNA contains uracil and uses ribose as the sugar. (B) RNA bases cannot form hydrogen bonds with each other. (C) RNA nucleotides use a different chemical linkage between nucleotides compared to DNA. (D) RNA is single-stranded.