Micro Exam 3: Chapter 8 Quiz

A gene is best defined as: A. A sequence of nucleotides in RNA that codes for a functional product. B. Any random segment of DNA. C. A sequence of nucleotides in DNA that codes for a functional product. D. Three nucleotides that code for an amino acid. E. The RNA product of a transcribed section of DNA.

According to the operon model, for the synthesis of an inducible enzyme to occur, the: A. End-product must not be in excess. B. Substrate must bind to the repressor. C. Repressor must not be synthesized. D. Repressor must bind to the operator. E. Substrate must bind to the enzyme.

An enzyme that copies DNA to make a molecule of RNA is: A. RNA polymerase. B. DNA polymerase. C. DNA helicase. D. DNA ligase. E. Transposase.

Conjugation differs from reproduction because conjugation: A. Replicates DNA. B. Transfers DNA vertically, to new cells. C. Transcribes DNA to RNA. D. Copies RNA to make DNA. E. Transfers DNA horizontally, to nearby cells without those cells undergoing replication.

DNA is constructed of: A. A single strand of nucleotides with internal hydrogen bonding. B. Two strands of identical nucleotides in a parallel configuration with hydrogen bonds between them. C. None of the ANSWERs is correct. D. Two strands of nucleotides running in an antiparallel configuration.

Genetic change in bacteria can be brought about by: A. All of the answers are correct. B. Mutation. C. Transformation. D. Conjugation. E. Transduction.

Table 8.1 Culture 1: F+, leucine+, histidine+ Culture 2: F-, leucine-, histidine- In Table 8.1, what will be the result of conjugation between cultures 1 and 2 (reminder: F+ has a different meaning than Hfr)? A. 1 will become F-, leu+, his+; 2 will become F+, leu-, his- B. 1 will become F-, leu-, his-; 2 will remain the same C. 1 will remain the same; 2 will become F+ and recombination may occur D. 1 will remain the same; 2 will become F+, leu+, his+ E. 1 will remain the same; 2 will become F+, leucine-, histidine-

Table 8.2 Codon on mRNA and corresponding amino acid UUA- leucine UAA- nonsense GCA- alanine AAU- asparagine AAG- lysine UGC- cysteine GUU- valine UCG, UCU- serine Refer to Table 8.2. The anticodon for valine is: A. CTT. B. GUU. C. CAA. D. GTA. E. CUU.

Table 8.2 Codon on mRNA and corresponding amino acid UUA- leucine UAA- nonsense GCA- alanine AAU- asparagine AAG- lysine UGC- cysteine GUU- valine UCG, UCU- serine Refer to Table 8.2. If the sequence of amino acids encoded by a strand of DNA is serine-alanine-lysine-leucine, what is the order of bases in the sense strand of DNA? A. 3' UGUGCAAAGUUA B. 5' AGAGCTTTGAAT C. 3' TCTCGTTTGTTA D. 5' TGTGCTTTCTTA E. 3' AGACGTTTCAAT

Synthesis of a repressible enzyme is stopped by the: A. End product binding to the promoter. B. Corepressor binding to the operator. C. Corepressor-repressor complex binding to the operator. D. Substrate binding to the repressor. E. Allosteric transition.

The cancer gene ras produces mRNA containing an extra exon that includes a number of UAA codons. Cancer cells produce ras mRNA missing this exon. This mistake most likely is due to a mistake by: A. Photolyases. B. UV radiation. C. DNA polymerase. D. A chemical mutagen. E. snRNPs.

The damage caused by ultraviolet radiation is: A. Repaired by DNA replication. B. Repaired during translation. C. Never repaired. D. Cut out and replaced. E. Repaired during transcription.

The initial effect of ionizing radiation on a cell is that it causes: A. The cells to get hot. B. DNA to break. C. Base substitutions. D. Bonding between adjacent thymines. E. The formation of highly reactive ions

The necessary ingredients for DNA synthesis can be mixed together in a test tube. The DNA polymerase is from Thermus aquaticus, and the template is from a human cell. The DNA synthesized would be most similar to: A. Human RNA. B. T. aquaticus DNA. Correct Answer C. Human DNA. D. T. aquaticus RNA. E. A mixture of human and T. aquaticus DNA.

Transformation is the transfer of DNA from a donor to a recipient cell: A. By crossing over. B. By cell-to-cell contact. C. By a bacteriophage. D. By sexual reproduction. E. As naked DNA in solution.

Which of the following pairs is mismatched? A. DNA gyrase — coils and twists DNA B. Transposase — insertion of DNA segments into DNA C. DNA polymerase — makes a molecule of DNA from a DNA template D. DNA ligase — joins segments of DNA E. RNA polymerase — makes a molecule of RNA from an RNA template

Which of the following statements is FALSE? A. DNA replication proceeds in only one direction around the bacterial chromosome. B. The lagging strand of DNA is started by an RNA primer. C. The leading strand of DNA is made continuously. D. DNA polymerase joins nucleotides in one direction (5' to 3') only. E. Multiple replication forks are possible on a bacterial chromosome.