1 PROTEIN PROTEIN SYNTHESIS SYNTHESIS copyright cmassengale DNA DNA and and Genes Genes 2copyright cmassengale DNA DNA • DNA contains genes, sequences of nucleotide bases • These Genes code for polypeptides (proteins) • Proteins are used to build cells and do much of the work inside cells 3copyright cmassengale 4 Genes & Proteins Genes & Proteins  Proteins are made of amino acids linked together by peptide bonds  20 different amino acids exist copyright cmassengale 5 Amino Acid Structure Amino Acid Structure copyright cmassengale 6 Polypeptides Polypeptides • Amino acid chains are called polypeptides copyright cmassengale 7 DNA Begins the Process DNA Begins the Process • DNA is found inside the nucleus • Proteins, however, are made in the cytoplasm of cells by organelles called ribosomes • Ribosomes may be free in the cytosol or attached to the surface of rough ER copyright cmassengale 8 Starting with DNA Starting with DNA • DNA ‘s code DNA ‘s code must be must be copied copied and taken to the cytosol and taken to the cytosol • In the cytoplasm, this In the cytoplasm, this code code must be read must be read so so amino acids amino acids can be assembled to make can be assembled to make polypeptides (proteins) polypeptides (proteins) • This process is called This process is called PROTEIN SYNTHESIS PROTEIN SYNTHESIS copyright cmassengale RNA RNA 9copyright cmassengale 10 Roles of RNA and DNA • DNA is the MASTER PLAN • RNA is the BLUEPRINT of the Master Plan copyright cmassengale [...]... Translation copyright cmassengale 25 Pathway to Making a Protein DNA mRNA tRNA (ribosomes) Protein copyright cmassengale 26 Protein Synthesis  The production or synthesis of polypeptide chains (proteins)  Two phases: Transcription & Translation  mRNA must be processed before it leaves the nucleus of eukaryotic cells copyright cmassengale 27 DNA → RNA → Protein Nuclear membrane DNA Transcription Eukaryotic... for a specific protein • Made up of 500 to 1000 nucleotides long • Sequence of 3 bases called codon • AUG – methionine or start codon • UAA, UAG, or UGA – stop 16 codons copyright cmassengale Ribosomal RNA (rRNA) • rRNA is a single strand 100 to 3000 nucleotides long • Globular in shape • Made inside the nucleus of a cell • Associates with proteins to form ribosomes • Site of protein Synthesis copyright... cmassengale 13 Three Types of RNA • Messenger RNA (mRNA) copies DNA’s code & carries the genetic information to the ribosomes • Ribosomal RNA (rRNA), along with protein, makes up the ribosomes • Transfer RNA (tRNA) transfers amino acids to the ribosomes where proteins are synthesized copyright cmassengale 14 Messenger RNA • Long Straight chain of Nucleotides • Made in the Nucleus • Copies DNA & leaves through... processed before it leaves the nucleus of eukaryotic cells copyright cmassengale 27 DNA → RNA → Protein Nuclear membrane DNA Transcription Eukaryotic Cell Pre-mRNA RNA Processing mRNA Ribosome Translation Protein copyright cmassengale 28 Transcription • The process of copying the sequence of one strand of DNA, the template strand • mRNA copies the template strand • Requires the enzyme RNA Polymerase copyright . polypeptides (proteins) • Proteins are used to build cells and do much of the work inside cells 3copyright cmassengale 4 Genes & Proteins Genes & Proteins  Proteins. assembled to make polypeptides (proteins) polypeptides (proteins) • This process is called This process is called PROTEIN SYNTHESIS PROTEIN SYNTHESIS copyright