Gene Expression, Genetic Code, and Mutations

Revision: Gene Expression in Prokaryotes vs. Eukaryotes\n\n* Prokaryotic Gene Expression:\n * DNA gene is directly transcribed into a messenger RNA (mRNA) molecule.\n * The mRNA molecule does not undergo any processing.\n * Information is immediately translated into the amino acid sequence of a polypeptide by a ribosome.\n\n* Eukaryotic Gene Expression:\n * More complex process involving several steps of RNA processing.\n * Transcription: RNA polymerase transcribes DNA gene into a pre-messenger RNA (pre-mRNA) transcript within the nucleus.\n * Pre-mRNA Modifications (within the nucleus):\n * Addition of a poly-A tail at the 3' end.\n * Addition of a 5' cap at the 5' end.\n * Splicing: Non-coding intron regions are cut out, and coding exon regions are spliced together to form the functional coding segment.\n * Mature mRNA: The fully processed mRNA molecule exits the nucleus through a pore in the nuclear envelope and enters the cytoplasm.\n\n# The Process of Translation\n\n* Aminoacyl tRNA Synthetases:\n * These are a group of 20 enzymes, one for each amino acid, located in the cytoplasm.\n * Their function is to connect specific amino acids to their corresponding transfer RNA (tRNA) molecules.\n * Each tRNA molecule has a specific anticodon that is complementary to the codon for its designated amino acid.\n * Once an amino acid is attached to the correct tRNA, the