Last period we discussed how DNA relates to the ADAPTATIONS in any organism and how these adaptations influence FITNESS. We learned that your elderly granny has demonstrated more fitness in her youth than you presently have and we explored how DNA TRANSCRIPTION and TRANSLATION turns a one dimensional genomic "sentence" into a three dimensional protein or POLYPEPTIDE CHAIN.
We learned that DNA is a code with an alphabet of only four nucleotide letters: ATCG and RNA differs only in the pyrimidine Uracil for AUCG. RNA is like DNA in another coding language. Also, The "words" that these nucleotides form are called CODONS and a group of CODONS can be translated into a strand of molecular pearls called a polypeptide chain made out of little "pearls" the AMINO ACIDS. The actors who orchestrate all this: The RIBOSOMES who read the RNA, AND THE tRNA who fetch the correct amino acid.
These AMINO ACIDS are polar and thus their positive and negative poles cause the strand of pearls to bend and fold into a meaningful SHAPE. This is the shape, colour and texture of life: The feathers, the colours, the textures, spider silk, eye lash, the retina of an elephant, blood protein. The shape of the protein is critical for its function, especially if that protein is an ENZYME.
An ENZYME is a biochemical catalyst and its SHAPE allows it to catalyze chemical reactions. If an enzyme changes shape it ceases to function. If all of our enzymes did that....it is a death sentence.
IN SUMMARY
DNA to RNA: TRANSCRIPTION
RNA to polypeptide chain: TRANSLATION
polypeptide chain folds into a correct 3D shape: PROTEIN SYNTHESIS
The Environment selects some organisms to live and some to die in an elimination game: NATURAL SELECTION
Next period: The Details of transcription , translation and protein synthesis
In addition to our Cartooon notes distributed in class, Here are some review materials for you.
DNA and Protein Synthesis, a summary of DNA replication (a review), and the Central Dogma of DNA, RNA and protein synthesis
DNA and Protein Synthesis worksheet
Fun converting DNA to RNA and RNA to Amino Acids
