Helicase is the enzyme that unwinds the DNA double helix, allowing the transcription machinery to access the template strand.

RNA polymerase is the enzyme that synthesizes the RNA molecule by adding nucleotides to the growing RNA chain.

Eukaryotes have three types of RNA polymerase: RNA polymerase I, RNA polymerase II, and RNA polymerase III, each with specific roles in transcribing different types of RNA molecules.

The promoter region is a region of DNA located upstream of the transcription start site that contains binding sites for transcription factors, serves as the site of transcription initiation, and is part of the DNA that is transcribed.

MicroRNA (miRNA), small interfering RNA (siRNA), and long non-coding RNA (lncRNA) are all types of RNA molecules that can regulate gene expression through various mechanisms.

Transcriptional repression, translational repression, and gene silencing are all mechanisms by which gene expression can be turned off or reduced.

Operons are a common mechanism for regulating gene expression in prokaryotes, where multiple genes are transcribed as a single unit and their expression is controlled by a single promoter.

Introns are non-coding sequences within eukaryotic genes that are removed during RNA processing (splicing) and are not part of the final mature RNA molecule.

Splicing, polyadenylation, and capping are all types of post-transcriptional modifications that can affect gene expression by altering the stability, localization, and translation of RNA molecules.

Transcription factors are proteins that bind to specific DNA sequences and regulate transcription initiation by either promoting or repressing the binding of RNA polymerase to the promoter region.

DNA methylation, histone acetylation, and histone methylation are all types of epigenetic modifications that can affect gene expression by altering the structure of chromatin and the accessibility of DNA to transcription factors and RNA polymerase.

Translation is the process by which a protein is synthesized from an mRNA molecule. During translation, the mRNA molecule is read by ribosomes, which use the genetic code to assemble amino acids into a polypeptide chain.

Transfer RNA (tRNA) is a type of RNA molecule that carries amino acids to the ribosome during translation. Each tRNA molecule is specific for a particular amino acid and recognizes the corresponding codon on the mRNA molecule.

The ribosome is a complex structure that assembles amino acids into a polypeptide chain during protein synthesis. It reads the mRNA molecule and uses the genetic code to determine the order of amino acids in the protein.

Phosphorylation, glycosylation, and ubiquitination are all types of post-translational modifications that can affect protein function by altering the protein's structure, activity, or localization.