Protein Synthesis

Prior Knowledge Protein: Large complex molecule that is essential to all life Synthesis: to build, put together Protein Synthesis: building of proteins Proteins are made from amino acids Sequence of nucleotides code for specific proteins Enzymes are proteins which control the chemical reactions in a cell DNA contains the codes therefore controls the cells. Ribosome: Place where proteins are assembled.

RNA Ribonucleic Acid “the workers” Take instructions from the DNA and build the proteins one amino acid at a time. Single Stands Sugar is Ribose Bases: Adenine, Uracil (pairs with Adenine), Guanine, Cytosine Three Types: mRNA tRNA rRNA

Types of RNA Messenger RNA (mRNA) Brings the DNA’s instructions from the nucleus to the cytoplasm to the ribosome. Ribosomal RNA (rRNA) Binds to mRNA and uses the instructions to assemble amino acids. Transfer RNA (tRNA) Brings amino acids to the ribosome to be assembled.

Transcription First step in the Protein Synthesis method DNA Helicase unzips the DNA Free RNA nucleotides pair with complimentary bases. A to U; C to G One portion of DNA is copied. RNA nucleotides bond together and form *ONE mRNA strand. * Different in DNA replication…two new strands are formed in DNA replication. mRNA strands leaves the nucleus and heads to the ribosomes. DNA strands reconnect.

Genetic Code mRNA contains a code using A’s, U’s, C’s, G’s. Complete instructions for building a protein Code must be converted into protein language

Genetic Code Codon: group of THREE nitrogenous bases code for ONE amino acid. Ex: UUU codes for Phenylalanine to be placed into a protein. Ex: UAA is a stop codon Ex: AUG is a start codon 64 combo’s are possible More than one codon can code for one amino acid UAU & UAC are both Tyrosine codons One Codon only codes for 1 amino acid UAU only codes for Tyrosine UCU only codes for Serine

Genetic Code ALL ORGANISMS USE SAME GENETIC CODE!!! SAME GENETIC CODE!!! First Base in Codon: C Second Base in Codon: A Third Base in Codon: U What does UAG code for? What does AGC code for? So…CAU codes for His (Histidine) Stop Serine

DNA Code: T A C /A C G /A T A/G T G /A T T A U G U G C U A U C A C U A A StartCystineTyrosineHistidineStop mRN Strand Protein

Translation Second Step in Protein Synthesis Occurs at the ribosomes Ribosome attaches to mRNA like a clothespin Sequence of bases is converted into sequence of amino acids Use Genetic Code Ex: CAU to Histidine Ex: UAG to Stop etc… tRNA brings needed amino acids to the ribosome to build the protein.

Translation tRNA has two sides amino acid side Nitrogenous base side Anticodon: 3 bases of tRNA on opposite end of amino acid Pair up with mRNA bases What is the anticodon for the following mRNA strand? A U G U A C

Translation Amino acids bond with each other Forms polypeptide bonds or PROTEINS!! This Process continues until a STOP codon is reached