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From Genes to Proteins. Biology 2121. Introduction. To produce a protein: Assemble amino acid – polypeptide chains DNA contains the necessary information DNA makes up chromosomes Chromosomes contain genes Chromosomes do not leave the nucleus
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From Genes to Proteins Biology 2121
Introduction • To produce a protein: • Assemble amino acid – polypeptide chains • DNA contains the necessary information • DNA makes up chromosomes • Chromosomes contain genes • Chromosomes do not leave the nucleus • Proteinsynthesis occurs on the surface of the ribosomes • Problem: How does the cell get the information to build a protein to the ribosomes?
Transcription • How is the language of DNA made available to the ribosomes to produce proteins? • DNA – genes are copied into mRNA • RNA differs from DNA • Adenine bonds with Uracil • “m” – messenger • Animation • Animation II
mRNA and Transcription • Transcriptionfactors loosen DNA histone proteins and bind to promoter • DNA strand to be copied – “template” • RNA-polymerase assembles nucleotides • RNA is processed • Pre-RNA • Exons: coding sections • Introns: non-coding sections spliced out
Translation • mRNA language is “translated” into the language of aminoacids. • mRNA triplet sections • Codon codes for one amino acid • Assembled on the ribosomes • tRNA – “transfer RNA” • Base pairs with the mRNA codon • Brings correct amino acid to the ribosome surface
The Genetic Code • Codons base pair with anti-codons on tRNA • Complete this mRNA segment: GGC CGA UUU • To identify the correct amino acid use the genetic code
Forming a polypeptide chain • Amino acids are assembled via peptide bonding
Protein Synthesis • Animation