The promoters of positively controlled operons require activator proteins, because
A) RNA polymerase easily recognizes the consensus sequence.
B) they are required to inactivate the repressor proteins.
C) the promoters have nucleotide sequences that bind RNA polymerase weakly, which are not close matches to the consensus sequence.
D) they are needed to bind to the allosteric site of RNA polymerase.
Answer: C
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In plant cells, auxin binds to a
a. cell surface receptor and triggers the ras/raf pathway. b. nuclear receptor that changes its shape so that it can bind to and activate genes. c. receptor ubiquitin ligase that stimulates the degradation of transcriptional repressors, resulting in activation of genes. d. cell surface molecule that stimulates fluid uptake.
If a pygmy were to mate with an African of normal size, the offspring would likely be intermediate in size.
a. true b. false
Enzymes that keep a constant amount or concentration with varying concentrations of substrate is known as:
Retroviruses have the enzyme ________ that catalyzes the synthesis of DNA from viral RNA.
What will be an ideal response?