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Human egg and sperm. Chapter 22. Nucleic Acids Sections Chemistry 121 Winter 2009 LA Tech Chapter 22-1 Chapter 22. Nucleic Acids-Sections 22.1 Types of Nucleic Acids 22.2 Nucleotides: Building Blocks of Nucleic Acids 22.3 Primary Nucleic Acid Structure 22.4 The DNA Double Helix 22.5 Replication of DNA Molecules 22.6 Overview of Protein Synthesis 22.7 Ribonucleic Acids Chemistry at a Glance: DNA Replication 22.8 Transcription: RNA Synthesis 22.9 The Genetic Code 22.10 Anticodons and tRNA Molecules 22.11 Translation: Protein Synthesis 22.12 Mutations Chemistry at a Glance: Protein Synthesis 22.13 Nucleic Acids and Viruses 22.14 Recombinant DNA and Genetic Engineering 22.15 The Polymerase Chain Reaction 22.16 DNA Sequencing Chemistry 121 Winter 2009 LA Tech Chapter 22-2 Adenine, a nucleic acid base Molecule of Adenine, a nitrogen-containing heterocyclic base present in both RNA and DNA. Chemistry 121 Winter 2009 LA Tech Chapter 22-3 Nucleic acid bases Two purine bases and three pyrimidine bases are found in the nucleotides present in nucleic acids. Chemistry 121 Winter 2009 LA Tech Chapter 22-4 Nucleotides Table 22.1 Chemistry 121 Winter 2009 LA Tech Chapter 22-5 Nucleic acid bases Chemistry 121 Winter 2009 LA Tech Chapter 22-6 Lipids cont’d Fig. 22.3 The general structure of a nucleic acid in terms of nucleotide subunits. Chemistry 121 Winter 2009 LA Tech Chapter 22-7 Backbone structure for nucleic acid (a) The generalized structure of a nucleic acid. (b) The specific backbone structure for a deoxyribonucleic acid (DNA). (c) The specific backbone structure for a ribonucleic acid (RNA). Chemistry 121 Winter 2009 LA Tech Chapter 22-8 DNA Fragment A four-nucleotidelong segment of DNA. Chemistry 121 Winter 2009 LA Tech Chapter 22-9 Protiens and DNA Comparison A comparison of the primary structures of nucleic acids and proteins. Chemistry 121 Winter 2009 LA Tech Chapter 22-10 DNA double helix A schematic drawing of the DNA double helix that emphasizes the hydrogen bonding between bases on the two chains. Chemistry 121 Winter 2009 LA Tech Chapter 22-11 Hydrogen bonding in Base Pairs Hydrogen bonding possibilities Chemistry 121 Winter 2009 LA Tech Chapter 22-12 DNA replication Chemistry 121 Winter 2009 LA Tech Chapter 22-13 DNA Replication One strand of DNA grows continuously in the direction of the unwinding, and the other grows in the opposite direction. Chemistry 121 Winter 2009 LA Tech Chapter 22-14 DNA replication at multiple sites DNA replication usually occurs at multiple sites within a molecule, and the replication is bidirectional from these sites. Chemistry 121 Winter 2009 LA Tech Chapter 22-15 What in Common Twins Have? Identical twins share identical physical characteristics because they received identical DNA from their parents. © Erica Stone / Peter Arnold, Inc. Chemistry 121 Winter 2009 LA Tech Chapter 22-16 DNA replication… cont’d Chemistry 121 Winter 2009 LA Tech Chapter 22-17 RNA hairpin loop A hairpin loop is produced when a single-stranded RNA doubles back on itself and complementary base pairing occurs. Chemistry 121 Winter 2009 LA Tech Chapter 22-18 Types of RNA Chemistry 121 Winter 2009 LA Tech Chapter 22-19 Transcription of DNA to form RNA The transcription of DNA to form RNA involves an unwinding of a portion of the DNA double helix. Chemistry 121 Winter 2009 LA Tech Chapter 22-20 Exons and Introns of RNA Heterogenous nuclear RNA contains both exons and introns. Chemistry 121 Winter 2009 LA Tech Chapter 22-21 Exons and Introns of RNA cont’d An hnRNA molecule containing four exons. Chemistry 121 Winter 2009 LA Tech Chapter 22-22 Codes for Amino Acids Chemistry 121 Winter 2009 LA Tech Chapter 22-23 tRNA molecule A tRNA molecule Chemistry 121 Winter 2009 LA Tech Chapter 22-24 Aminoacyl-tRNA synthetase An aminoacyl-tRNA synthetase has an active site for tRNA and a binding site for the particular amino acid that is to be attached to that tRNA. Chemistry 121 Winter 2009 LA Tech Chapter 22-25 Anticodon and Codon The interaction between anticodon an codon. Chemistry 121 Winter 2009 LA Tech Chapter 22-26 Ribosome Structure Ribosomes have structures that contain two subunits. Chemistry 121 Winter 2009 LA Tech Chapter 22-27 Protein Synthesis: Initiation Initiation of protein synthesis begins with the formation of an initiation complex. Chemistry 121 Winter 2009 LA Tech Chapter 22-28 Protein Synthesis: Translation The process of translation that occurs during protein synthesis. Chemistry 121 Winter 2009 LA Tech Chapter 22-29 Effects of Antobiotics Chemistry 121 Winter 2009 LA Tech Chapter 22-30 Polysome Several ribosomes can simultaneously proceed along a single strand of mRNA. Such a complex of mRNA and ribosomes is called a polysome. Chemistry 121 Winter 2009 LA Tech Chapter 22-31 Protien Synthesis Summary Chemistry 121 Winter 2009 LA Tech Chapter 22-32 Influenza virus. Image of an influenza virus. NIBSC / SPL / Photo Researchers Chemistry 121 Winter 2009 LA Tech Chapter 22-33 Recombinant DNA Recombinant DNA is made by inserting a gene obtained from DNA of one organism into the DNA from another kind of organism. Chemistry 121 Winter 2009 LA Tech Chapter 22-34 Cleaving DNA patterns using restriction enzymes Cleavage patterns resulting from the use of a restriction enzyme that cleaves DNA between G and A bases. Chemistry 121 Winter 2009 LA Tech Chapter 22-35 “sticky ends” of recombnants The “sticky ends” of the cut plasmid and the gene are complementary and combine to form recombinant DNA. Chemistry 121 Winter 2009 LA Tech Chapter 22-36 Polymerase chain reaction process Chemistry 121 Winter 2009 LA Tech Chapter 22-37 Polymerase chain reaction process Chemistry 121 Winter 2009 LA Tech Chapter 22-38 DNA sequencing Selected steps in the DNA sequencing procedure for the 10-base DNA segment 5’ AGCAGCTGGT 3’. Chemistry 121 Winter 2009 LA Tech Chapter 22-39 Nucleic Acids - RNA and DNA Nucleic acid is a complex, high-molecular-weight biochemical macromolecule composed of nucleotide chains that convey genetic information. The most common nucleic acids are deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). Nucleic acids are found in all living cells and viruses. Chemistry 121 Winter 2009 LA Tech Chapter 22-40 Nucleotides Nucleotides are the building blocks of DNA and RNA. • Serve as molecules to store energy and reducing power. • The three major components in all nucleotides are phosphoric acid, pentose (ribose and deoxyribose), and a base (purine or purimidine). • Two major purines present in nucleotides are adenine (A) and guanine (G), and three major purimidines are thymine (T), cytosine (C) and uracil Chemistry 121 Winter 2009 LA Tech Chapter 22-41 (U). Chemistry 121 Winter 2009 LA Tech Chapter 22-42 Ribonucleotides Adenosine triphosphate (ATP) and guanosine triphosphate (GTP), which are the major sources of energy for cell work. - The phosphate bonds in ATP and GTP are high-energy bonds. - The formation of phosphate bonds or their hydrolysis is the primary means by which cellular energy is stored or used. nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP). The two most common carriers of reducing power for biological oxidation-reduction reactions. Chemistry 121 Winter 2009 LA Tech Chapter 22-43 Deoxyribonucleic Acid (DNA) Deoxyribonucleic acid (DNA) is formed by condensation of deoxyribonucleotides. 3 The nucleotides are linked together between the 3’ and 5’ carbons’ successive pentose rings by phosphodiester bonds Chemistry 121 Winter 2009 LA Tech 5 Chapter 22-44 Deoxyribonucleic Acid (DNA) - DNA is a very large threadlike macromolecule (MW, 2X109 D in E. coli). - DNA contains adenine (A) and guanine (G), thymine (T) and cytosine (C). - DNA molecules are two stranded and have a double-helical three-dimensional structure. Chemistry 121 Winter 2009 LA Tech Chapter 22-45 DNA Double-helical Structure Chemistry 121 Winter 2009 LA Tech Chapter 22-46 Double Helical DNA Structure The main features of double helical DNA structure are as follows: . - The phosphate and deoxyribose units are on the outer surface, but the bases point toward the chain center. The plane of the bases are perpendicular to the helix axis. - The diameter of the helix is 2 nm, the helical structure repeats after ten residues on each chain, at an interval of 3.4 nm. - The two chains are held together by hydrogen bonding between pairs of bases. Adenine (A) - thymine (T), guanines (G) - cytosine (C). - The sequence of bases along a DNA strand is not restricted any way and carries genetic Chemistry 121 Winter 2009 in LA Tech Chapter 22-47 information, and sugar and phosphate groups DNA Replication Regeneration of DNA from original DNA segments. http://highered.mcgraw-hill.com/sites/0072437316/student_view0/chapter14/animations.html# http://www.ncc.gmu.edu/dna/repanim.htm Chemistry 121 Winter 2009 LA Tech Chapter 22-48 http://www.lewport.wnyric.org/jwanamaker/animations/DNA%20Replication%20-%20long%20.htm DNA Replication - DNA helix unzips and forms two separate strands. - Each strand will form a new double strands. - The two resulting double strands are identical, and each of them consists of one original and one newly synthesized strand. - This is called semiconservative replication. - The base sequences of the new strand are complementary to that of the parent strand. Chemistry 121 Winter 2009 LA Tech Chapter 22-49 Ribonucleic Acid (RNA) Ribonucleic acid (RNA) is formed by condensation of ribonucleotides. RNA is a long, unbranched macromolecule and may contain 70 to several thousand nucleotides. RNA molecule is usually single stranded. RNA contains adenine (A), guanine (G), cytosine (C) and uracial (U). A-U, G-C in some double helical regions of t-RNA. Chemistry 121 Winter 2009 LA Tech Chapter 22-50 Classification of RNA According to the function of RNA, it can be classified as: Messenger RNA: (m-RNA) synthesized on chromosome and carries genetic information to the ribosomes for protein synthesis. It has short half-life. Transfer RNA (t-RNA) is a relatively small and stable molecule that carries a specific amino acid from the cytoplasm to the site of protein synthesis on ribosomes. Ribosomal RNA (r-RNA) is the major component of ribosomes, constituting nearly 65%. r-RNA is responsible for protein synthesis. Ribozymes are RNA molecules that have catalytic properties. Chemistry 121 Winter 2009 LA Tech Chapter 22-51 Summary of Nucleic Acids Nucleotides are basic units of nucleic acids DNA and RNA. Nucleotides include pentose, base and phosphoric acid. Bases include purine or pyrimidine. Two major purines present in nucleotides are adenine (A) and guanine (G), and three major pyrimidines are thymine (T), cytosine (C) and uracil (U). Ribonucleotides - adenosine triphosphate (ATP) stores energy. - NAD and NADP are important carriers of reducing power. Chemistry 121 Winter 2009 LA Tech Chapter 22-52 Summary of Nucleic Acids DNA DNA contains genetic information. DNA contains adenine (A) and guanine (G), and thymine (T), and cytosine (C). A-T G-C DNA has a double helical structure. The bases in DNA carry the genetic information. Chemistry 121 Winter 2009 LA Tech Chapter 22-53 Summary of Nucleic Acids RNA • RNA functions as genetic information-carrying intermediates in protein synthesis. • It contains adenine (A) and guanine (G), and cytosine (C) and uracil (U). • m-RNA carries genetic information from DNA to the ribosomes for protein synthesis. • t-RNA transfers amino acid to the site of protein synthesis • r-RNA is for protein synthesis. Chemistry 121 Winter 2009 LA Tech Chapter 22-54 Summary of Cell Construction Biopolymers protein Carbohydrates (polysaccharides) DNA RNA lipids subunit bonds for subunit linkage functions Characteristic three-D structure Chemistry Chemistry 121 Winter 2009 LA Tech 55 Chapter 22-55