ellthompso55-
T/F E. Coli Sigma Factors all recognize one E. Coli gene
F
-
T/F E. Coli sigma factors all bind to the core RNA polymerase
T
-
T/F Bacterial mRNAs contain sequences for sigma factor binding
F
-
T/F mRNA never contains the nucleotide sequence encoding just one protein
F
-
T/F mRNA always contains the nucleotide sequence encoding just one protein
F
-
T/F There are 64 codons that each code for one of the standard 20 amino acids
F
-
T/F Each tRNA has its own aminoacyl tRNA synthetase
F - each amino acid has its own tRNA
-
T/F The wobble position is the third base in a codon
T
-
T/F Leucine has 6 different codons that are about equal in abundance in E. Coli
T
-
T/F Some of the nucleotides in tRNA are routinely modified
T
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RNA Polymerase:
Can synthesize RNA chains de novo (without a primer)
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Which of the following statements about E. Coli RNA polymerase is false?
The core enzyme has no polymerizing activity until the sigma subunit is bound
-
The sigma factor of E. Coli RNA polymerase
Combines with the core enzyme to confer specific binding to a promoter
-
The mRNA for a polypeptide chain of molecular weight 50,000 has a minimum length of:
14,000 (50,000/110
*3)
-
A single base change in an mRNA may result in
all of the above
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Which of the following statements about ribosomes is true?
There are two major subunits, each with multiple proteins
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Housekeeping genes in bacteria are commonly expressed constitutively, but not all of these genes are expressed at the same level (the same number of molecules per cell). What is a primary mechanism responsible for variation in the level of constitutive enzymes?
Different genes have slightly different promoters, with different affinities for RNA polymerase holoenzyme
-
The operator region normally can be bound by:
repressors
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The DNA binding motif which is crucial to the interaction of many prokaryotic regulatory proteins, as exemplified by the lac repressor is:
helix-turn-helix
