Biochemistry Essay

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DNA REPLICATION DNA Replication and Protein Synthesis (Hudon-Miller, 2013) DNA Replication • DNA’s structure is a double helix. • Helicase breaks apart the strands of DNA and the single stranded DNA proteins keep the strands from joining together again. • RNA primase adds a RNA primer to each strand. This primer gives DNA polymerase III something to hold onto when it starts to add DNA nucleotides to the stands. • DNA polymerase III always moves in a 5’ to 3’ direction. • There are two strands that are formed: a leading strand and a lagging strand. • The leading strand allows DNA polymerase III to add nucleotides continuously. The lagging strand must have multiple RNA primers, though. This strand forms Okazaki fragments between the primers. • (Hudon-Miller, 2013) (Hudon-Miller, 2013) DNA Ligase • DNA polymerase I removes the RNA primers and places DNA nucleotides in its place. • DNA ligase then comes along to seal the spaces between the Okazaki fragments together. • (Hudon-Miller, 2013) (Wolfe, 2000) Protein Synthesis • Protein synthesis starts in the nucleus of a cell. RNA polymerase forms mRNA from a parent DNA strand. This is called transcription. Then the mRNA strand moves to the cytoplasm. • In the cytoplasm, mRNA will link up with two ribosomes to make a complete ribosome. These ribosomes will then link up tRNA with the mRNA and attach the amino acids carried by the tRNA to each other. This forms an amino acid chain, or a protein. This process is called translation. • (Wolfe, 2000) Death Cap Mushrooms • Death cap mushrooms are highly toxic • They contain a toxin called ⍺- amanitin, which inhibits RNA polymerase (Hudon-Miller, 2012). • If RNA polymerase is inhibited, mRNA will not be created and then ribosomes will not be able to link together amino acids to make proteins for the cells. • Without proteins, many chemical

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