RNA Splicing and the Expanded Genetic Code (Biology Mind Map)

RNA Splicing and the Expanded Genetic Code (Biology Mind Map)

Description: This diagram displays the process of RNA Splicing, which occurs on mRNA strands within eukaryotic cells (ie. those with a nucleus) in the time between transport from the nucleus to the cytoplasm. DNA segments are often broken into "introns" and "exons", the former being rather useless for the functional protein and the latter being crucial to creating a functioning protein. Splicesomes, groups of proteins and RNAs, attach to the necessary points in order to remove introns from the original mRNA. The modified mRNA containing only exons is then ready to be translated. It is translated by ribosomes in groups of three which pair an amino acid based on the reading for that group of three (ex. AUG). Which amino acid this will be depends on the expanded genetic code which was cracked in 1961 by Marshall Warren Nirenberg and J. Heinrich Matthaei. The diagram states that "the genetic code is redundant but not ambiguous." This means that while multiple triplets may pair to a single amino acid, every single triplet is paired to only a single amino acid. The diagram also contains an image for the "one gene - one enzyme" hypothesis which states that one gene is related to one phenotype. While this was an earlier idea of geneticists, today we find that the situations are oftentimes more complex.