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Question
What is the function of phosphoribosyltransferases?a. they are involved in the reversible reactions of purine salvage.
b. they mediate the degradation of AMP.
c. they are central to the re-synthesis of nucleotides from bases in salvage reactions.
d. they mediate the degradation of IMP.
e. they are competitive inhibitors employed in the salvage of purine nucleotides.
Answer
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Related questions
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In general, proteins whose folding is chaperone-dependent start the folding process first with ____ and then are passed as ____ folded intermediates to ____.
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b. Hsp90; un-; chaperonin
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d. Hsp40; partially; Hsp70
e. Hsp60; partially; Hsp40
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d. mutation in the huntingtin gene
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In a class I aminoacyl-tRNA synthetase, which of the following reacts with the acyl phosphate formed during the reaction of ATP with the amino acid?a. 5'-hydroxyl of the nucleotide on the 5' end of the tRNA moleculeb. 3'-hydroxyl of the nucleotide on the 5' end of the tRNA moleculec. 2'-hydroxyl of the nucleotide on the 5' end of the tRNA moleculed. 3'-hydroxyl of the nucleotide on the 3' end of the tRNA moleculee. 2'-hydroxyl of the nucleotide on the 3' end of the tRNA molecule
Q:
Each of the following statements regarding ways in which eukaryotic protein synthesis differs from prokaryotic protein synthesis is true EXCEPT:
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e. all of the above are true statements
Q:
Ribosome:mRNA:P-site tRNA complex, with the help of ____, is disassembled by ____ which is an excellent molecular mimic of a(n) ____.
a. ATP; tRNA terminator; GTP
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Q:
Termination of translation in prokaryotic cells requires:
a. binding of the terminator tRNA to the termination codon.
b. interaction of release factors with the termination codon.
c. ternary interaction of the release factor and the termination tRNA with the termination codon.
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Q:
Which of the following does not reqire GTP hydrolysis?
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b. the binding of the aminoacyl tRNA to the A site during elongation
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Q:
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Q:
Mitochondrial and chloroplastic ribosomes resemble ____ ribosomes.
a. prokaryotic
b. lower eukaryotic
c. higher eukaryotic
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b. asp; ala; polycationic
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Q:
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Q:
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Q:
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Q:
The genetic code is said to be degenerate, which means that:
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The linkage between the amino acid and the tRNA in an amino-acyl tRNA complex is:
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The araBAD operon allows for the use of what metabolite by E. coli?
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Q:
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Q:
Transcription of a typical gene encoding a polypeptide in eukaryotes involves all of the following EXCEPT:
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Q:
The base-pair edges in the ____ groove act as a(n) ____ identifiable through ____ with specific proteins.
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Q:
The eukaryotic transcription factor that exhibits a sequence specificity for the TATA box is:
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Q:
All are correct about enhancer sequences in eukaryotic cells EXCEPT:
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Q:
All are characteristics of catabolic activator protein (CAP) EXCEPT:
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The base in DNA that specifies the first base in the RNA transcript is called a(n) ____ and is numbered ____.a. promoter; -5b. enhancer; -35c. transcription start site; 0d. transcription start site; +1e. promoter complex; +5
Q:
Which of the following would most likely cause a frameshift mutation?
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b. a base analog such as 5-bromouracil
c. a chemical mutagen such as nitrous acid
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Q:
Which of the following statements explains why the adenine analog, 2-aminopurine (2-AP), can cause mutations in DNA when it is inserted in place of a site normally occupied by A?
a. 2-AP forms 2 hydrogen bonds with thymine
b. 2-AP undergoes oxidative deaminiation to hypoxanthine which basepairs with C
c. 2-AP can form a single hydrogen bond with C
d. 2-AP is often found as a schiff base that crosslinks with T
e. none of the above
Q:
Misincorporation of all subsequent amino acids results from ____ mutations.
a. chemical
b. base shift
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Q:
Mutations in DNA may result from all of the following EXCEPT:
a. spontaneous mutations due to errors in replication.
b. physical insults on the cell, such as UV light.
c. errors in transcription.
d. chemical mutagens.
e. introduction of a base analog into DNA.
Q:
A transition mutation would be replacing A by:
a. T.
b. C.
c. U.
d. G.
e. either T or C