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
RNA Polymerase:
Can synthesize RNA chains de novo (without a primer)
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
Which of the following statements about ribosomes is true?
There are two major subunits, each with multiple proteins
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
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