biology test 4 notes

biology test 4 notes - Test 4 Notes: Gene Expression,...

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Test 4 Notes: Gene Expression, By: Group 21 (Watch this video to pump you up to study! ) http://www.youtube.com/watch? Learning Objectives Gene Expression: Decoding the flu 1. Distinguish among the functions of DNA, mRNA, tRNA, and proteins. a. DNA – Deoxyribonucleic Acid – DNA is the genetic code that ensures that daughter cells inherit the same characteristics of the parent cell. It is the code from which all proteins are synthesized. All prokaryotes, eukaryotes, and some virus’ have DNA. DNA is composed of four nucleotide bases : Adenine, Guanine, Thymine, Cytosine. DNA contains all the genetic coding used to control functions, behavior, and development of an organism. It is a long-term storage device for genetic instructions. DNA must be correct so it can make an exact copy of itself. Function of DNA in a cell is to code the way proteins, turn genes on or of. a.i. DNA Replication: DNA unwinds, each of the single strands of the original molecule serves as a template or pattern for the creation of a second DNA strand. Bases on one strand pair one at a time with free floating bases until a second strand is created. b. mRNA – Messenger RNA - Is a type of RNA that encodes and carries to ribosomes information for the synthesis of proteins. They are the instructions for the creation of a protein. Proteins are made in ribosomes, and are made from amino acids. Each molecule of mRNA carries instructions how to connect amino acids into a peptide chain. Each of life’s twenty amino acids are coded by a series of three nitrogenous bases in RNA nucleotides. Each triplet of RNA nucleotides corresponds to one amino acid. Sequence of nucleotides dictates the sequence of amino acids that will be linked into the peptide chain. mRNA tells the amino acid how to align to make a specific protein. c. tRNA – Transfer RNA can be defined as a form of RNA that, in protein synthesis, binds with amino acids, transfers them to ribosomes, and then binds with messenger RNA. Each type of tRNA molecule can only be attached by one amino acid. But because genetic code has various codons that show the same amino acid, tRNA molecules hold different anticodons that may or may not hold the same amino acid. d. Proteins – Many proteins are enzymes that catalyze biochemical reactions that are vital to metabolism. They have a structural or mechanical function. They can maintain cell shape. Their chief function is their ability to bind other molecules. They can help carryout the replication of DNA by protein synthesis.
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2. Explain how cells use information stored in DNA to make proteins. a. Most genes contain the information needed to make proteins. It consists of two major steps transcription and translation. Together transcription and translation is called gene expression. a.i.
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This note was uploaded on 01/19/2012 for the course BIOL 1103 taught by Professor Armstrong during the Fall '07 term at UGA.

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biology test 4 notes - Test 4 Notes: Gene Expression,...

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