Chapter 17 - Chapter 17 1 Transcription vs translation 2 1 gene 1 enzyme 3 Transcription translation on prokaryotes A gene dictates the production

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Chapter 17 1. Transcription vs. translation 2. 1 gene- 1 enzyme 3. Transcription/ translation on prokaryotes - A gene dictates the production of a specific enzyme - Figure 17.2- Beadle and Tatum experiment- 1gene- 1 enzyme. o Purpose- why so important? 1 gene- 1 enzyme hypothesis- states that the function of a gene is to dictate the production of a specific enzyme. How body/ plants work What they learned Not all proteins are enzymes o Examples- keratin and insulin 1 gene- I polypeptide hypothesis o 1. Many euk. Genes can code for a set of closely related polypeptides in a process called alternative splicing o 2. A lot of genes code for RNA molecules that have important func. In cells even tho they are never translated into proteins Some mutants needed other precursors to form Certain classes of mutants lacked particular enzymes that catalyzes the blocked step - Basic principles of transcription and translation o Genes provide instructions for making specific proteins Gene don’t directly build protein Bridge between DNA and protein synthesis is the nucleic acid- RNA Bases for DNA: A, T, G, C Bases for RNA: A, U, G, C o Flow genetic information: DNA mRNA protein Gene expression - process by which DNA directs the synthesis of proteins Includes 2 steps: transcription and translation Both nucleic acids and proteins are polymers with specific sequences of monomers that convey info In DNA and RNA sequences, the monomers are the 4 types of nucleotides, which differ in their nitrogenous bases Genes usually = 100s 1000s nucleotides long. From DNA protein requires: transcription and translation o Transcription - is the synthesis of RNA under the direction of DNA. Nucleic acid are the same and information is transcribed, or copied from one molecule to the other.
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A DNA strand can serve as a template for assembling a complementary sequence of RNA nucleotides. Messenger RNA (mRNA )-type of RNA molecule, that carries a genetic message from the DNA to the protein- synthesizing machinery of the cell. o Translation - synthesis of a polypeptide, which occurs under the direction of mRNA. Change in language Site of translation are ribosomes , complex particles that facilitate the orderly linking of amino acids into polypeptide chains. - 1 bacterial cell- 1 strand DNA - Main difference of prokaryote vs eukaryote o Prokaryote Nucleus- Prokaryote doesn’t have a membrane bound nucleus Don’t have nuclei DNA is not segregated from ribosomes and other protein- synthesizing equipment. o Because lack segregation allows translation of mRNA to begin while transcription is still in progress. Prok. – bacteria
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This note was uploaded on 11/13/2011 for the course BIOLOGY 1132 taught by Professor Shannon during the Spring '10 term at The University of Texas at San Antonio- San Antonio.

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Chapter 17 - Chapter 17 1 Transcription vs translation 2 1 gene 1 enzyme 3 Transcription translation on prokaryotes A gene dictates the production

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