BIO Chapter 7

25 July 2022
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Gene expression:
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the process of converting archived information into molecules that actually do things in the cell
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knock-out, null, or loss-of-function allels:
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Alleles that do not function
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Which of the following is(are) post-transcriptional modifications occurring in eukaryotic mRNAs? a) addition of a methyl-guanosine cap b) removal of introns c) addition of a poly (A) tail d) all of the above
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d
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What are the steps (in the correct order) that link a change in the base sequence of a gene to a change in the phenotype of an organism like a mouse or a human? a) Protein—>RNA—>DNA b) DNA—>RNA—>Protein c) RNA—>DNA—>Protein d) DNA—>Protein—>RNA
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b
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The idea that the sequence of bases in DNA specifies the sequence of bases in an RNA molecule, which specifies the sequence of amino acids in a protein, is _______. a) the central dogma b) the one-gene, one-enzyme hypothesis c) the codon hypothesis d) the Neurospora biosynthetic hypothesis e) the neutral theory
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a
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According to the original central dogma, what macromolecule or phenomenon is directly responsible for an organism's phenotype? a) mutation b) DNA c) protein d) transcription e) RNA
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c
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Which of the following is NOT synthesized from a DNA template? a) messenger RNA b) ribosomal RNA c) tRNA d) amino acids
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d
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In the process of transcription, _____. a) proteins are synthesized b) DNA is replicated c) RNA is synthesized d) mRNA attaches to ribosomes
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c
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Given the DNA template shown in the figure above, which of the following bases would you find in a complementary RNA strand and where would they be synthesized? a) A-A-A-A-A; ribosome b) A-A-A-A-A; nucleus c) U-U-U-U-U; ribosome d) U-U-U-U-U; nucleus
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b
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Genotype is to _____ as phenotype is to _____. a) gene regulation; translation b) DNA base sequence; physical traits that are products of the proteins produced c) transcription; amino acid sequence d) heredity; DNA base sequence
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b
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Once researchers identified DNA as the unit of inheritance, they asked how information was transferred from the DNA in the nucleus to the site of protein synthesis in the cytoplasm. What is the mechanism of information transfer in eukarotes? a) Transfer RNA takes information from DNA directly to a ribosome, where protein synthesis takes place. b) Messenger RNA is transcribed from a single gene and transfers information from the DNA in the nucleus to the cytoplasm, where protein synthesis takes place. c) DNA from a single gene is replicated and transferred to the cytoplasm, where it serves as a template for protein synthesis. d) Proteins transfer information from the nucleus to the ribosome, where protein synthesis takes place.
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b
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How does the simple primary and secondary structure of DNA hold the information needed to code for the many features of multicellular organisms? a) The width of the double helix changes at each gene due to differences in hydrogen bonds. b) The amino acids that make up the DNA molecule contain the information needed to make cellular proteins. c) The base sequence of DNA carries the information needed to code for proteins. d) The hydrogen bonding among backbone constituents carries coded information.
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c
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In eukaryotic cells, transcription cannot begin until _____. a) DNA nucleases have isolated the transcription unit b) the DNA introns are removed from the template c) the two DNA strands have completely separated and exposed the promoter d) the 5' caps are removed from the mRNA e) several transcription factors have bound to the promoter
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e
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Which of the following processes is central to the initiation of transcription? a) binding of DNA polymerase to the promoter region b) formation of a phosphodiester bond in the elongating RNA strand c) binding of sigma to the promoter region d) formation of a DNA primer
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c
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What is responsible for termination of transcription in eukaryotic protein-coding genes? a) three nonsense mutations in sequence b) a sigma factor c) a portion of the polymerase holoenzyme d) a termination loop composed of guanine e) a polyadenylation signal or poly(A)
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e
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5' caps and 3' poly(A) tails of eukaryotic mRNAs ______. a) protect mRNA from degradation and enhance transcription b) protect mRNA from degradation and enhance translation c) act as sites for the start and stop of translation, respectively d) mark the beginning and end of introns, respectively
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b
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Which one of the following statements about RNA processing is true? a) Ribozymes may function in RNA splicing. b) RNA splicing can be catalyzed by tRNA. c) A primary transcript is often much shorter than the final RNA molecule that leaves the nucleus. d) Exons are cut out before mRNA leaves the nucleus.
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a
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Suppose that an induced mutation removes most of the 5' end of the 5' UTR of an mRNA. What is most likely to happen? a) Removal of the 5' UTR also removes the 5' cap and the mRNA will quickly degrade. b) The 3' UTR will duplicate and one copy will replace the 5' end. c) The first exon will not be read because I1 will now serve as the UTR. d) Removal of the 5' UTR will have no effect because the exons are still maintained.
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a
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Refer to the figure above. The mRNA is smaller than the length of the DNA that codes for it because _____. a) bases are added to the tail of the primary transcript b) post-transcriptional modification removes the introns c) the regulatory regions (exons) of the gene are not transcribed d) post-transcriptional modification removes the exons
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b
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Starting at the 5' end, what is the base sequence of the RNA strand shown in Figure 4.3? a) CGAU b) UGAC c) TAGC d) UAGC
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d