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Genetics Chapter 12

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livelove90's version from 2012-04-02 16:02

Section

Question Answer
When considering the initiation of transcription, one often finds consensus sequences located in the region of the DNA where RNA polymerase(s) bind. Which are common consensus sequences?
A)CAAT, TATA
B)GGTTC, TTAT
C)TTTTAAAA, GGGGCCCC
D)any trinucleotide repeat
E)satellite DNAs
A
What is the name given to the three bases in a messenger RNA that bind to the anticodon of tRNA to specify an amino acid placement in a protein?
A)protein
B)anti-anticodon
C)cistron
D)rho
E)codon
E
An intron is a section of
A)protein that is clipped out posttranslationally.
B)RNA that is removed during RNA processing.
C)DNA that is removed during DNA processing.
D)transfer RNA that binds to the anticodon.
E)carbohydrate that serves as a signal for RNA transport.
B
The genetic code is fairly consistent among all organisms. The term often used to describe such consistency in the code is
A)universal.
B)exceptional.
C)trans-specific.
D)overlapping.
E)none of the above
A
Which of the following sets of two terms relates most closely to split genes?
A)5'-cap, 3'-poly-A tail
B)introns, exons
C)elongation, termination
D)transcription, translation
E)heteroduplex, homoduplex
B
Significant in the deciphering of the genetic code was the discovery of the enzyme polynucleotide phosphorylase. What was this enzyme used for?
A)the manufacture of synthetic RNA for cell-free systems
B)ribosomal translocation
C)peptide bond formation
D)production of ribosomal proteins
E)degradation of RNA
A
In 1964, Nirenberg and Leder used the triplet binding assay to determine specific codon assignments. A complex of which of the following components was trapped in the nitrocellulose filter?
A)ribosomes and DNA
B)free tRNAs
C)charged tRNA, RNA triplet, and ribosome
D)uncharged tRNAs and ribosomes
E)sense and antisense strands of DNA
C
What is the initiator triplet in both prokaryotes and eukaryotes? What amino acid is recruited by this triplet?
A)UAA; no amino acid called in
B)UAA or UGA; arginine
C)AUG; arginine
D)AUG; methionine
E)UAA; methionine
D
Select three posttranscriptional modifications often seen in the maturation of mRNA in eukaryotes.
A)5'-capping, 3'-poly(A) tail addition, splicing
B)3'-capping, 5'-poly(A) tail addition, splicing
C)removal of exons, insertion of introns, capping
D)5'-poly(A) tail addition, insertion of introns, capping
E)heteroduplex formation, base modification, capping
A
The genetic code is said to be triplet, meaning that
A)there are three amino acids per base in mRNA.
B)there are three bases in mRNA that code for an amino acid.
C)there may be three ways in which an amino acid may terminate a chain.
D)there are three "nonsense" triplets.
E)none of the above
B
When scientists were attempting to determine the structure of the genetic code, Crick and co-workers found that when three base additions or three base deletions occurred in a single gene, the wild-type phenotype was sometimes restored. These data supported the hypothesis that
A)the code is triplet.
B)the code contains internal punctuation.
C)AUG is the initiating triplet.
D)the code is overlapping.
E)there are three amino acids per base.
A
When examining the genetic code, it is apparent that
A)there can be more than one amino acid for a particular codon.
B)AUG is a terminating codon.
C)there can be more than one codon for a particular amino acid.
D)the code is ambiguous in that the same codon can code for two or more amino acids.
E)there are 44 stop codons because there are only 20 amino acids.
C
The relationship between a gene and a messenger RNA is that
A)genes are made from mRNAs.
B)mRNAs are made from genes.
C)mRNAs make proteins, which then code for genes.
D)all genes are made from mRNAs.
E)messenger RNA is directly responsible for making Okazaki fragments.
B
A class of mutations that results in multiple contiguous (side-by-side) amino acid changes in proteins is probably caused by the following type of mutation:
A)frameshift.
B)transversion.
C)transition.
D)base analog.
E)recombinant.
A
Introns are known to contain termination codons (UAA, UGA, or UAG), yet these codons do not interrupt the coding of a particular protein. Why?
A)UAA, UGA, and UAG are initiator codons, not termination codons.
B)Exons are spliced out of mRNA before translation.
C)These triplets cause frameshift mutations, but not termination.
D)More than one termination codon is needed to stop translation.
E)Introns are removed from mRNA before translation.
E
It has been recently determined that the gene for Duchenne muscular dystrophy (DMD) is over 2000 kb (kilobases) in length; however, the mRNA produced by this gene is only about 17 kb long. What is a likely cause of this discrepancy?
A)The exons have been spliced out during mRNA processing.
B)The DNA represents a double-stranded structure, while the RNA is single-stranded.
C)There are more amino acids coded for by the DNA than the mRNA.
D)The introns have been spliced out during mRNA processing.
E)When the mRNA is produced, it is highly folded and therefore less long.
D
If one compares the base sequences of related genes from different species, one is likely to find that corresponding ________ are usually conserved, but the sequences of ________ are much less well conserved.
A)exons; introns
B)introns; exons
C)introns; chaperons
D)chaperons; exons
E)introns; proteins
A
Three posttranscriptional modifications often seen in the maturation of mRNA in eukaryotes occur in which cellular organelle? A)nucleus
B)cytoplasm
C)mitochondrion
D)lysosome
E)Golgi
A
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