Ribonucleic acid (RNA)

In eukaryotes, RNA Polymerase I is specialized for transcribing the major ribosomal RNA genes within the nucleolus.

The large ribosomal subunit contains rRNA that acts as a ribozyme (peptidyl transferase) to catalyze peptide bond formation.

Introns are non-coding regions that must be excised, and exons are the coding sequences that are ligated together to form mature mRNA.

Written from the 3' to 5' direction (or 5'-CCA-3' read towards the 3' terminus), this terminal sequence attaches to the specific amino acid.

Aminoacyl-tRNA synthetase is the specific enzyme that catalyzes the esterification of a specific amino acid to its cognate tRNA.

The poly-A tail protects mRNA from 3' exonucleases, extending its operational lifespan within the cytoplasm.

Without a nuclear envelope separating DNA from ribosomes, prokaryotes can simultaneously transcribe and translate a genetic message.

AUG is the universal start codon that codes for methionine in eukaryotes and formyl-methionine in prokaryotes.

Complementary bases within the single-stranded tRNA bend back and form hydrogen bonds, creating its characteristic shapes.

A nucleoside consists only of a sugar and a base; adding a phosphate group converts it into a nucleotide.

Ribose contains a hydroxyl group (-OH) at the 2' carbon position, distinguishing it from deoxyribose which has a hydrogen atom instead.

Uracil is a pyrimidine base specific to RNA that pairs with adenine, replacing the thymine found in DNA.

Phosphodiester bonds form the sugar-phosphate backbone by connecting the 3' carbon of one ribose to the 5' carbon of the next.

The nucleolus is a specialized region within the nucleus dedicated to the transcription of rRNA and the assembly of ribosomal subunits.

Messenger RNA (mRNA) serves as a linear transcript of the genetic blueprint to guide amino acid sequencing during translation.

Ribosomal RNA is the most abundant form of RNA in the cell because ribosomes are present in vast numbers to meet translational demands.

Messenger RNA is synthesized as a single-stranded linear molecule to allow ribosomes to read its codons sequentially.

The 3' end of tRNA terminates in a conserved CCA sequence, where the hydroxyl group of the terminal adenine binds to an amino acid.

Purines are double-ringed nitrogenous bases, which include adenine and guanine in both DNA and RNA.