生物dna复制经典选择例题（Examples of classic selection of biological DNA replication）.docVIP

生物dna复制经典选择例题（Examples of classic selection of biological DNA replication） Radio In 1.1958 years, experiments on Meselson and StAhl using 15N and 14N labeled Escherichia coli DNA first demonstrated which of the following mechanisms? A.DNA can be copied The B.DNA gene can be transcribed into mRNA C.DNA gene can be expressed as protein D.DNAs mechanism of semi retained replication E.DNA total retention replication mechanism 2.DNA replicates in a semi - reserved manner. What happens if a fully labeled DNA molecule replicates two generations in a non - radioactive solution, producing four DNA molecules? A. two molecules are radioactive, two molecules are not radioactive B. is radioactive C. two in the chain half radioactive D. one of two strands having radioactivity No radioactivity was found in E. 3. if one of the following enzymes is absent, one of the nucleotides on the replication fork cannot be added. What kind of enzyme is this? A.DNA synthase I (polymerization activity) B.DNA polymerase (5 - 3 exonuclease activity) C.DNA polymerase III D.DNA ligase E.DNA polymerase II 4. what is the effect of thymine two, which occurs in DNA, as a mutation? A. does not terminate replication B. is repaired by a group of enzymes including ligase C. read by shift mutation D. is catalyzed by thymine two enzyme Covalent bonds between thymine strands on E. two strands of complementary nucleotides Which of the following enzymes is not needed for 5.DNA replication? A.DNA directed DNA polymerase. B.DNA directed RNA polymerase C. ligase D.RNA directed DNA polymerase E. helix enzyme (helieAse), topological isomerase (topoisomerAse) and helicase (gyrAse). Hui @ Jiao Zi $/xueHuiEdu.Com 6. which of the following statements about the reproduction of DNA is wrong? A. has DNA directed RNA polymerase to participate B. has RNA directed DNA polymerase to participate C. is a semi reserved copy D. is made from four kinds of dNTP E. has DNA directed DNA polymerase to participate When 7.DNA replicates,