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Question
Which of the following weak acids would make the best buffer at pH = 5.0?a. acetic acid (Ka = 1.74 x 10-5, pKa = 4.76)
b. H2PO4- (Ka = 1.38 x 10-7, pKa = 7.20)
c. bicarbonate (Ka = 6.3 x 10-11, pKa = 10.24)
d. tris-hydroxymethyl aminomethane (Ka = 8.32 x 10-9, pKa = 8.07)
e. lactic acid (Ka = 1.38 x 10-4, pKa = 3.86)
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 ____.
a. Hsp40; un-; Hsp70
b. Hsp90; un-; chaperonin
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d. Hsp40; partially; Hsp70
e. Hsp60; partially; Hsp40
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Which of the following is responsible for Alzheimer's disease?
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c. extracellular deposits of amyloid-ï¢ and intracellular neurofibrillary tangles of microtubule-binding protein tau
d. mutation in the huntingtin gene
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Q:
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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b. prokaryotes use a 30S small ribosomal subunit, while eukaryotes use a 40S small ribosomal subunit
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Q:
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Q:
Termination of translation in prokaryotic cells requires:
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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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Q:
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Q:
Mitochondrial and chloroplastic ribosomes resemble ____ ribosomes.
a. prokaryotic
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c. higher eukaryotic
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Q:
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e. arg; lys; polyanionic
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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b. An anticodon can interact with more than one codon in the mRNA in which the codon may differ in any or all of the three nucleotides.
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d. The code is universally used by virtually all species.
e. None are true.
Q:
The linkage between the amino acid and the tRNA in an amino-acyl tRNA complex is:
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d. an ether
e. an ester
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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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c. transcription of DNA corresponding to both introns and exons.
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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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Q:
Characteristics of rho factor include all EXCEPT that it:a. recognizes and binds C-rich regions of RNA transcripts.b. binding regions must be ribosome free.c. advances in the 5'->3' direction to the transcription bubble.d. unwinds transcript and template to free nascent RNA.e. all are true.
Q:
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
d. an intercalation agent such as acridine orange
e. none of the above
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?
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b. 2-AP undergoes oxidative deaminiation to hypoxanthine which basepairs with C
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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
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e. all are true
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