32P-end-labeled DNA fragment contains the AP-1–binding site sequence. The DNA was mixed with Fos, FosC (a fragment of Fos), or Jun (all of which would form a homodimer), or with a mixture of Fos and Jun or a mixture of FosC and Jun (both of which would form the two types of homodimer and the heterodimer). Reactions were analyzed by polyacrylamide gel electrophoresis, then autoradiography.  The results are shown below.   This technique is called:

Which of the following is NOT a characteristic of a riboswitch?

The phosphorylation of eIF2 inhibits translation initiation by:

______________ are DNA elements that stimulate transcription even when they are located a great distance from the transcription initiation site.

The presence of two copies of the X-chromosome in females but only one in males poses a potential problem for regulation of gene expression: everything else being equal, the higher copy number of the X-linked genes can lead to an imbalanced overproduction of their products in females compared to males. Organisms have evolved different ______  mechanisms to solve this problem. In mammals, for example, the almost complete inactivation of one of the X chromosomes provides the solution to the dosage problem.

Which of the following is NOT required during the elongation phase of translation in bacteria?

In the E. coli RecBCD pathway, in order for homologous recombination to occur, which of the following proteins coats the single stranded DNA tail produced by exonuclease activity?

In prokaryotes, the Shine Dalgarno sequence attracts ribosomes to the AUG site.

The upstream activator sequence for the GAL genes (UASGAL) is recognized by:

Studying the expression of a transcription regulatory protein in two cell types, you have performed experiments showing that the mRNA encoding the protein is present at comparable levels in the cytosol of both cell types. However, based on the expression of its target genes, you suspect that the protein activity might be significantly different in the two cell types. Which of the following steps in expression of the gene encoding this protein is more likely to be differentially controlled in these cell types?