3. Energy & Cell Processes

In eukaryotic cells, transcription cannot begin untila. the two DNA strands have completely separated and exposed the promoter.b. several transcription factors have bound to the promoter.c. the 5′ caps are removed from the mRNA.d. the DNA introns are removed from the template.

The RNA polymerase enzyme binds to , initiating transcription.a. amino acids;b. tRNA;c. the promoter sequence;d. the ribosome

In a particular bacterial species, temperature-sensitive conditional mutations cause expression of a wild-type phenotype at one growth temperature and a mutant phenotype at another—typically higher—temperature. Imagine that when a bacterial cell carrying such a mutation is shifted from low to high growth temperatures, RNA polymerases in the process of elongation complete transcription normally, but no new transcripts can be started. The mutation in this strain most likely affects:a. the terminator sequenceb. the start codonc. sigmad. one of the polypeptides of the core RNA polymerase

In a particular bacterial species, temperature-sensitive conditional mutations cause expression of a wild-type phenotype at one growth temperature and a mutant phenotype at another—typically higher—temperature. Imagine that when a bacterial cell carrying such a mutation is shifted from low to high growth temperatures, RNA polymerases in the process of elongation complete transcription normally, but no new transcripts can be started. The mutation in this strain most likely affects:a. the terminator sequenceb. the start codonc. sigmad. one of the polypeptides of the core RNA polymerase