Journal #4: In DNA, which nucleotide pairs with Adenine? Guanine? Which DNA nucleotide is not represented in RNA? Fun Fact: Every human spent about half an hour as a single cell Objective 3: Summarize the process of protein synthesis Homework: Transcription & Translation Diagrams

Gene Activation & Protein Synthesis Pgs

Gene Activation Each DNA molecule houses thousands of genes tightly coiled around histones –Genes have instructions to make proteins Genes uncoil and histones are removed when a gene becomes active –Promoters: start each gene Histones uncoil 2 complimentary DNA strands unzip –RNA polymerase binds to the promoter –Transcription occurs Messenger RNA is made mRNA leaves goes to the cytoplasm to synthesize protein

Transcription of mRNA Step 1: DNA strands separate and RNA polymerase attaches to the template strand (complimentary triplets- codons) Step 2: RNA polymerase begins attaching the complimentary nucleotides to the mRNA chain –Adenine, Guanine, Cytosine, & Uracil (instead of Thymine as in DNA) Step 3: At the stop codon the mRNA detaches from the DNA strand

RNA Processing Introns- nonsense regions of mRNA Exons- coding segments Before the mRNA leaves the nucleus the introns must be snipped out and the exons spliced together –Regulation of this “editing” is not yet explained by science

Translation AKA: Protein Synthesis Reading the code from the mRNA to make a protein Starts with codon-AUG for start – The anticodon UAC brings the amino acid methionine to start the amino acid chain Ribosomes (in the cytoplasm) join the amino acids together as directed by the tRNA to form the directed protein Ends with a stop codon

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