CHAPTER 8

A gene is best defined as ___

• a segment of DNA

• three nucleotides that code for an amino acid

• a transcribed unit of DNA

• a sequence of nucleotides in RNA that codes for a functional product

• a sequence of nucleotides in DNA that codes for a functional product

Which of the following pairs is mismatched?

• Transposase – insertion of DNA segments into DNA

• DNA gyrase – coils and twists DNA

• RNA polymerase – makes a molecule of RNA from an RNA template

• DNA polymerase – makes a molecule of DNA from a DNA template

• DNA ligase – joins segments of DNA

An enzyme that makes covalent bonds between nucleotide sequences in DNA is ___

• DNA gyrase

• Topoisomerase

• DNA polymerase

• DNA ligase

An enzyme that copies DNA to make a molecule of RNA is ___

• Topoisomerase

• DNA ligase

• RNA polymerase

• DNA gyrase

• DNA Polymerase

An enzyme that synthesizes, proofreads and repairs DNA is ___

• DNA gyrase

• DNA Polymerase

• Topoisomerase

• DNA ligase

• RNA polymerase

Which of the following statements is false?

• Multiple replication forks are possible on a bacterial chromosome.

• DNA replication proceeds in one direction around the bacterial chromosome.

• The lagging strand of DNA is started by an RNA primer.

• DNA polymerase joins nucleotides in one direction only.

• The leading strand of DNA is made continuously.

DNA is constructed of ___ .

• nucleotides bonded A–C and G–U

• nucleotides bonded A–C and G–T

• two strands of identical nucleotides with hydrogen bonds between them

• a single strand of nucleotides with internal hydrogen bonding

• two strands of nucleotides running antiparallel

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 ___ .

• human RNA

• a mixture of human DNA and T. aquaticus DNA

• human DNA

• T. aquaticus RNA

Which of the following is NOT a product of transcription?

• rRNA

• A new strand of DNA

• none of these choices

• mRNA

• tRNA

The antibiotic chloramphenicol binds the 50S ribosome. From this information you can conclude that chloramphenicol ___ .

• prevents transcription in prokaryotes

• prevents translation in prokaryotes

• prevents translation in eukaryotes