Chapter 9

A geneticist has discovered a yeast cell, which encodes a DNA polymerase that may add nucleotides in both the \(5^{\prime}\) to \(3^{\prime}\) and \(3^{\prime}\) to \(5^{\prime}\) directions. Which of the following structures would this cell NOT likely generate during DNA replication? (A) RNA primers (B) Okazaki fragments (C) Replication fork (D) Nicked DNA by topoisomerases

A eukaryotic gene, which does not normally undergo splicing, was exposed to benzopyrene, a known carcinogen and mutagen. Following exposure, the protein encoded by the gene was shorter than before exposure. Which of the following types of genetic rearrangements or mutations was likely introduced by the mutagen? (A) Silent mutation (B) Missense mutation (C) Nonsense mutation (D) Duplication

DNA replication occurs through a complex series of steps involving several enzymes. Which of the following represents the correct order beginning with the earliest activity of enzymes involved in DNA replication? (A) Helicase, ligase, RNA primase, DNA polymerase (B) DNA polymerase, RNA primase, helicase, ligase \(\quad\) (C) RNA primase, DNA polymerase, ligase, helicase \(\quad\) (D) Helicase, RNA primase, DNA polymerase, ligase

If a messenger RNA codon is UAC, which of the following would be the complementary anticodon triplet in the transfer RNA? (A) ATG (B) \(\mathrm{AUC}\) (C) \(\mathrm{AUG}\) (D) ATT

During post-translational modification, the polypeptide from a eukaryotic cell typically undergoes substantial alteration that results in (A) excision of introns (B) addition of a poly(A) tail (C) formation of peptide bonds (D) a change in the overall conformation of a polypeptide

Which of the following represents the maximum number of amino acids that could be incorporated into a polypeptide encoded by 21 nucleotides of messenger RNA? (A) 3 (B) 7 (C) 21 (D) 42

A researcher uses molecular biology techniques to insert a human lysosomal membrane protein into bacterial cells to produce large quantities of this protein for later study. However, only small quantities of this protein result in these cells. What is a possible explanation for this result? (A) The membrane protein requires processing in the ER and Golgi, which are missing in the bacterial cells. (B) Bacteria do not make membrane proteins. (C) Bacteria do not use different transcription factors than humans, so the gene was not expressed. (D) Bacteria do not have enough tRNAs to make this protein sequence.

BamHI is a restriction enzyme derived from Bacillus amyloliquefaciens that recognizes short palindromic sequences in DNA. When the enzyme recognizes these sequences, it cleaves the DNA. What purpose would restriction enzymes have in a bacterium like Bacillus? (A) They are enzymes that no longer have a purpose because evolution has produced better enzymes. (B) They destroy extra DNA that results from errors in binary fission. (C) They protect Bacillus from invading DNA due to viruses. (D) They prevent, or restrict, DNA replication when the cell isn't ready to copy its DNA.

Viruses and bacteria have which of the following in common? (A) Ribosomes (B) Nucleic acids (C) Flagella (D) Metabolism

Griffith was a researcher who coined the term transformation when he noticed that incubating nonpathogenic bacteria with heat-killed pathogenic bacteria produced bacteria that ultimately became pathogenic, or deadly, in mice. What caused the transformation in his experiment? (A) DNA from the nonpathogenic bacteria revitalized the heat-killed pathogenic bacteria. (B) Protein from the pathogenic bacteria was taken up by the nonpathogenic bacteria. (C) DNA from the pathogenic bacteria was taken up by the nonpathogenic bacteria. (D) DNA in the nonpathogenic bacteria turned into pathogenic genes in the absence of pathogenic bacteria.

A biologist systematically removes each of the proteins involved in DNA replication to determine the effect each has on the process. In one experiment, after separating the strands of DNA, she sees many short DNA/RNA fragments as well as some long DNA pieces. Which of the following is most likely missing? (A) Helicase (B) DNA polymerase (C) DNA ligase (D) RNA primase