Genetics Unit Module 9: Transcription and Translation   Copyright 2013 University of Washington. All rights reserved. Content developed by the Institute for Science and Mathematics Education, University of Washington, Seattle, Washington, U.S.A. ©2013 Educurious Partners. All rights reserved. www.educurious.org

Basic Molecular Biology Information in cells flows from DNA to RNA to protein Transcription: Synthesis of messenger RNA (mRNA) Uses DNA as template Takes place in nucleus Translation: Synthesis of protein via transfer RNA (tRNA) and amino acids Uses mRNA as template Takes place in ribosomes ©2013 Educurious Partners. All rights reserved. www.educurious.org

Steps of Transcription Double strands of DNA “unzip” by protein action 2. mRNA strand is built, using DNA as template following base-pairing rules 3. mRNA leaves nucleus for the ribosomes in the cytoplasm Image from http://www.lba.cnptia.embrapa.br/Bioinf/gui/content/tools/fasta/transcription.gif ©2013 Educurious Partners. All rights reserved. www.educurious.org

©2013 Educurious Partners. All rights reserved. www.educurious.org mRNA mRNA is similar in structure to DNA EXCEPT THAT mRNA IS: Single stranded Sugar = ribose, instead of deoxyribose Uses the nitrogenous base uracil instead of thymine ©2013 Educurious Partners. All rights reserved. www.educurious.org

Protein Synthesis: Translation 1. mRNA is used to synthesize amino acids in the ribosome. Every 3 letters of the mRNA is a codon sequence. 2. Codons are equated (using base-pairing rules) by tRNA into anticodons. 3. Anticodons are translated into amino acids, brought to the ribosome by tRNA. http://commons.wikimedia.org/wiki/File:Peptide_syn.png ©2013 Educurious Partners. All rights reserved. www.educurious.org

Protein Synthesis: Translation 4. Amino acids are strung together forming a polypeptide, which makes up part of, or a whole, protein. http://en.wikipedia.org/wiki/File:Main_protein_structure_levels_en.svg ©2013 Educurious Partners. All rights reserved. www.educurious.org

Protein Synthesis: Structure The sequence of amino acids in a polypeptide determines the primary structure of the protein, through: Chemical interactions between amino acids Physical properties of the amino acids example: Hydrophobicity is the inability of a molecule to interact with water http://en.wikipedia.org/wiki/File:Main_protein_structure_levels_en.svg ©2013 Educurious Partners. All rights reserved. www.educurious.org

Protein Synthesis: Structure Other physical interactions help to determine the protein’s structure at different organizational levels: that is coiling into helix, folding of coils, attaching of side chains. wikipedia ©2013 Educurious Partners. All rights reserved. www.educurious.org

©2013 Educurious Partners. All rights reserved. www.educurious.org Protein Synthesis Example: Enzymes are types of proteins that fit at an active site with other specific molecules (substrates) to accelerate chemical reactions - If there are any structural changes in the active site, the enzyme won’t function The structure of a protein determines its function http://commons.wikimedia.org/wiki/File:Lock_and_key_model.png ©2013 Educurious Partners. All rights reserved. www.educurious.org

©2013 Educurious Partners. All rights reserved. www.educurious.org Proteins Of all molecules in animals, proteins are the most abundant. They are found in muscle tissues, enzymes, and antibodies. ©2013 Educurious Partners. All rights reserved. www.educurious.org

Transcription and Translation Animation Watch the excerpt from “Secret of Life” https://www.youtube.com/watch?v=D3fOXt4MrOM ©2013 Educurious Partners. All rights reserved. www.educurious.org

Visualizing Molecular Processes Optionally, watch the Dr. Drew Berry TEDx Talk to help you “see” these complex cellular process at work: http://tedxtalks.ted.com/video/TEDxCaltech-Drew-Berry-Visualiz ©2013 Educurious Partners. All rights reserved. www.educurious.org