Ribsome

• Ribosome is a very small structure found in all living cells that plays a crucial role in protein synthesis.
• Ribosome consists of two main subunits, comprised of RNA and proteins, which read genetic code and assemble amino acids into polypeptide chains.
• Small subunit of ribosome decodes genetic information started in MRNA.
• Large subunit of ribosome catalyzes the formation of peptide bonds between amino acids to form a polypeptide chain.
• Ribosome is highly ordered, with the RNA molecules forming a scaffold that positions the proteins in the correct orientation to carry out their functions.
• Ribosome is an intercellular structure made of RNA and protein, serving as the site of protein synthesis in cells.
• Ribosome reads the MRNA sequence and translates that genetic code into a specified string of amino acids.
• Amino acids grow into long chains that fold to form protein.
• Protein synthesis starts at AUG and initiator tRNA always carries formylmethionine, meaning all newly made proteins have methionine.
• Protein synthesis involves the elongation of a chain, which includes peptide bond formation, large-wide translocation, small-subunit translocation, and ribosome movement.
• Initiator tRNA remains at P site, A site is vacant and protein synthesis begins.
• Eukaryotic initiation factors (eIFs) are involved in the loading of the initiator tRNA-Methionine Complex into the small ribosomal subunit.
• Elongation in transcription involves RNA polymerase beginning to move down the DNA template in the 3' to 5' direction, adding complementary nucleotides.
• The start of protein synthesis is important as errors could result in misreading or functioning.
• Termination in transcription can occur as soon as the polymerase reaches the termination sequence, but in some cases a termination factor (protein) is also needed.
• Transcription regulation involves the binding of RNA polymerase and transcription factors to the DNA strand at a specific area that facilitates transcription, known as the promoter region.
• Small ribosomal subunit then binds to the 5' end of mRNA molecule and moves up 5' to find AUG.
• The insulin-producing cluster of the pancreas contains transcripts for insulin but bone cells do not despite carrying the gene for insulin.
• Initiation factors dissociate, allowing the large ribosomal subunit to assemble with complete ribosome.
• Initiator tRNA-Methionine Complex is loaded into small ribosomal subunit along with protein.
• Transcription is the process where nucleotide sequence spells out the sequence of AAs in proteins.
• The biological function of a protein is determined by its 3D structure which is determined by the linear sequence of the AAs.
• Bases pair up when free nucleotides attach to complementary bases along the new strands using RNA polymerase.
• mRNA is the most variable class of RNA.
• Each cell in a Multicellular organism carries the same DNA, its transcriptome Varies according to cell type & function.
• The 4-letter alphabet of DNA translates to a 20-letter alphabet of protein.
• More protein is synthesised in Active Cells (rapidly growing = high protein synthesis).
• The remaining mass of ribosomes consists of over 80 different proteins.
• A new backbone is formed when Sugar-phosphate is assembled to complete the RNA strand.
• The accuracy of protein synthesis can be maintained by ensuring that the correct reading name is ensured.
• RNA molecules (ribozyme/Catalytic RNA) direct the Catalytic steps of protein synthesis.
• RNA Polymerase II synthesises mRNA, which requires transcription factors to initiate transcription.
• DNA unzips when enzymes (enzymatic Scissors) split apart base pairs and unwinds the DNA double-helix.
• The life-span of mRNA transcripts can vary, for example, transcripts for signalling proteins may be degraded in 10mins, while transcripts for Structural proteins may remain intact for >10 his.
• Conveyor belt process of ribosomes involves the small (30s) and large (70s) subunits.
• DNA transcription involves a single-strand RNA Molecule complementary to one strand of the DNA double-helix sequence of bases in the RNA Molecule is the same as the sequence of bases in the DNA template.
• Many different mRNA molecules are present in a cell at any given time, with some mRNA abundant, others rare.
• mRNA cap is a highly methylated modification of the 5' end of RNA polymerase II transcribed RNA, which protects RNA from degradation, recruits complexes involved in RNA processing, export, translation, and marks Cellular mRNA as 'self' to avoid recognition by the innate immune system.