The "central dogma" of molecular biology, as explained by a bakery analogy скачать в хорошем качестве

The "central dogma" of molecular biology, as explained by a bakery analogy

Proteins are way cooler than cookies and cakes, but a more fun analogy the cake does make! So how do you open, manage, & shut down protein bakeries? Explaining GENE REGULATION the bumbling biochemist way! Which I think could make a great “Inside Out 2” that, instead of taking you into a brain, takes you inside a cell making proteins. blog form (adapted from past post): https://bit.ly/centraldogma_bakery Proteins are cellular “workers” made up of amino acid building blocks. I like to think of them as “baked goods” like cookies & cakes. Cells are constantly dealing w/different demands, to which they have to be able to adapt their supply to meet. There are many different ways in which they do this & the further down the protein production pipeline, the more quickly effects can be seen, but the less efficient the process (like turning off a faucet vs cleaning up the mess) The cellular nucleus is like the corporate headquarters that directs the opening of franchise bakeries by issuing messenger RNA (mRNA) copies of recipes for various protein “baked goods.” Cells can regulate how many bakeries in each chain they open (transcriptional control); how many bakers each chain hires & how efficient those bakers are (translational control); how long the bakery stays open (mRNA regulation); and how “well the product sells” and when it expires (post-translational control) The original recipes are written in DNA in the form of genes, bound together into “cookbook volumes” called chromosomes housed in a membrane-bound room in your cells called the nucleus. To make a protein, the cells make an messenger RNA (mRNA) copy of the gene-encoded recipe in a process called TRANSCRIPTION, then (if it passes the security check) the mRNA recipe gets sent out into the general part of the cell (CYTOPLASM) where they’re used to start “bakeries” where “bakers” called ribosomes turn it into a protein in a “baking” process called TRANSLATION. These “bakeries” are called mRNPs - messenger RNA containing ribonucleoprotein complexes. Short acronym for long words which tell you you have a group of proteins & RNAs bound to a protein recipe (mRNA). The only “constant” in the bakery is the recipe (mRNA) - binding partners vary throughout the mRNA’s lifetime depending on what needs to be done (e.g. swap out proteins that help w/start-up construction phase to ones that specialize in maximizing productivity to ones that help w/shutting down the bakery). The mRNA sequence is also the only “unique” part about the bakery, so the other components can be reused. So they have to be “cross-compatible” → they often bind to the “generic parts” of mRNAs. Most of the text in the mRNA is “templated” meaning that it comes word-for-word from the DNA version. But mRNA also has extra “generic” words put on in the form of a polyadenylate (poly-A) tail & a 7mG at the beginning. In addition to offering generic “latch-on” points for proteins, the cap & tail serve as a kind of “watermark” that tells the cell they’re legit. more here: http://bit.ly/mRNAbiochemistry & https://bit.ly/mrnalife The “bakers” are called RIBOSOMES & they’re complexes of proteins & ribosomal RNA (rRNA) molecules that read the recipe and link together the corresponding amino acids (protein letters). They know what to add because 3-letter RNA words (codons) spell one amino acid letter. The baker moves along the recipe & “calls out” the next amino acid to be added → biochemically, what’s happening is the ribosome is translocating along the mRNA (taking 3-nt-long steps) & as it does so it exposes the next codon in its A site. Then a tRNA “servant” brings it the corresponding amino acid. more here: https://bit.ly/proteintranslationwedding &    • Protein translation - it's an amino acid w...   There are 4 RNA letters (A, U, C, & G) so 64 codons - 1 (AUG) spells start (& methionine) & 3 spell stop → When a stop codon shows up, instead of tRNA binding, release factors bind (proteins pretending to be tRNA that come with scissors) → cut off growing chain and free the baker which can then start making another protein (either at this bakery or a different one) finished in comments