举一反三
- Which of the following statements about non-coding DNA is true ()? A: DNA sequences that do not encode proteins B: DNA sequences that do not encode RNA and proteins C: DNA sequence without function D: DNA sequence without phenotype after deletion<br/>[单选题][2分][难度3]
- 以下哪个与基因表达激活有关 (Which of the following is associated with activation of gene expression ?) A: H3K4甲基化 (H3K4 methylation) B: H3K9甲基化 (H3K9 methylation) C: DNA promoter的甲基化 (Methylation of DNA promoter) D: 组蛋白的去乙酰化 (Deacetylation of histones)
- The B form DNA is the only natural conformation of DNA.()
- The A form and Z form DNA are not the natural conformation of DNA.
- The role of RNA primer during DNA replication is A: to guide DNA polymerase to bind with DNA template B: to provide 5’ phosphate end C: to provide attachment sites for four kinds of NTP D: to provide 3’-OH end to initiate synthesis of new DNA
内容
- 0
Which of the following are NOT true about DNA polymerase I in E. coli: A: It can repair the gap in the single-strand DNA. B: It can replace DNA polymerase III to add dNTP into DNA chain when DNA template is damaged. C: Using dNTP as substrate. D: It possesses activity of 5’→3’ endonuclease.
- 1
(+)DNA即是与mRNA序列互补的DNA.
- 2
Which is correct about DNA polymerase and RNA polymerase: A: RNA polymerases use nucleoside diphosphate instead of nucleoside triphosphate for synthesis of polynucleotide chains B: RNA polymerases need primer and add nucleotides in the 5 'end of the polynucleotide chain C: DNA polymerase can add nucleotides in both ends of the polynucleotide chain D: All of the RNA polymerases and DNA polymerases can only add nucleotides in the 3’ end of the polynucleotide chain
- 3
DNA replication requires: (1) DNA polymerase III, (2) helicase, (3) DNA polymerase I, (4) DNA-directed RNA polymerase, (5) DNA ligase, the correct order of their participation is: A: 2,3,4,1,5 B: 4,2,1,5,3 C: 4,2,1,3,5 D: 2,4,1,3,5
- 4
Which gene transfer technique involves a tiny needle which is used to inject DNA into a cell lacking that DNA sequence