BIO NMDCAT

RNA polymerases possess the unique biochemical capacity to initiate the synthesis of a new polynucleotide chain completely de novo.

Uncharged tRNAs lack attached amino acids; their buildup indicates that the cell is running low on amino acids to fuel protein translation.

The physical stress of the hairpin combined with the weak hydrogen bonds of the U-rich stretch forces the transcript to detach from the DNA template.

The A (aminoacyl) site welcomes the newly arrived, charged tRNA molecule carrying the next amino acid to be added to the growing peptide chain.

The P (peptidyl) site retains the tRNA molecule attached to the evolving polypeptide chain before transferring it to the incoming A-site tRNA.

Capping enzymes require the 5' triphosphate terminal structure of the nascent RNA transcript to successfully link the inverted guanosine cap.

The anticodon loop exposes three nucleotide bases designed to form anti-parallel hydrogen bonds with the matching mRNA codon triplet.

Eukaryotic structural genes are organized as split sequences where protein-coding regions (exons) are interrupted by non-coding regions (introns).

The coding (sense) DNA strand matches the mRNA transcript sequence exactly, with the sole exception that thymine (T) is replaced by uracil (U).

A polysome (or polyribosome) consists of a single mRNA strand being translated simultaneously by several moving ribosomes to amplify protein yield.

Nucleic acid strands align anti-parallelly; therefore, the 5'-AUG-3' codon pairs with the 3'-UAC-5' (or 5'-CAU-3') anticodon.

Transcription produces an RNA strand complementary and anti-parallel to the DNA template strand, replacing thymine with uracil.

The chemical reactivity of the 2'-OH group allows RNA to participate in catalytic mechanisms, giving rise to ribozymes.

The 23S rRNA located in the large (50S) prokaryotic ribosomal subunit acts as the peptidyl transferase ribozyme.

RNA viruses possessing RNA-dependent RNA polymerase can replicate their RNA directly from an RNA template without creating a DNA intermediate.

Alpha-amanitin, a toxin from the death cap mushroom, is a highly specific inhibitor of eukaryotic RNA Polymerase II.

A nonsense mutation converts an amino acid-specifying codon into a termination codon (UAA, UAG, or UGA), shortening the final protein.

Rho factor is an ATP-dependent helicase that tracks along the growing RNA transcript to unwind the RNA-DNA hybrid and terminate transcription.

Transcription initiation begins with a nucleoside triphosphate without clearing the pyrophosphate, leaving a 5'-triphosphate terminal.