Practice Questions

The ribosome checks only the codon-anticodon match. The 3'-UUG-5' anticodon will pair with a 5'-AAC-3' codon, incorrectly introducing methionine.

In basic solutions, the 2'-OH group of ribose is deprotonated, launching a nucleophilic attack on the adjacent phosphorus atom that breaks the RNA backbone.

The sigma subunit is a transient initiation factor that grants the core prokaryotic RNA polymerase structural specificity to bind promoters.

In historical genetic code experiments, UUU was discovered to be the specific codon that codes for the amino acid phenylalanine.

Small nucleolar RNAs (snoRNAs) reside within the nucleolus and act as guide RNAs that direct the biochemical modification and splicing of pre-rRNA.

The structural domains of rRNA inside the A and P binding sites form precise non-covalent contacts to align the tRNA for peptide synthesis.

Double-stranded RNA is a hallmark of viral replication; eukaryotic cells use the Dicer and RISC pathways to recognize and destroy it.

The D-loop gets its name from containing dihydrouracil and plays a key structural role in recognition by aminoacyl-tRNA synthetase.

The size and weight of an mRNA molecule depend entirely on the length of the specific polypeptide chain it is meant to code for.

Short-lived mRNA allows bacteria to quickly shut down old metabolic pathways and transcribe new genes when conditions change.