DOCSLIB.ORG

Nucleotide and Nucleic Acid Structure

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Nucleotide and Nucleic Acid Structure IntroductionNucleotide to Cells & Microscopy and Nucleic Acid Structure Adapted from Prof. Dean Tolan • Outline of today’s supplemental lecture • Nucleotide and nucleic acid structure • Central Dogma • Replication • Transcription • Translation • Quiz at the end of the lecture Structural Components of Nucleotides Glycosidic bond Table 3-1 Nucleic acid – polymer of nucleotides – directionality 5’3’ When you write a sequence: ATCG It is assumed that the 5’-end is on the left and the 3’-end is on Phosphodiester bond the right, unless otherwise labeled. 5’-ATCG-3’ Chargaff’s Rules B-Form DNA http://higheredbcs.wiley.com/legacy/college/voet/0470129301/kinemages/exercise_2.html Figure 3-8 Computer-simulated space-filling model of DNA. Video: Computer-simulated space-filling model of DNA. SUMMARY (34 Å) Right-handed, antiparallel, double- sugar–phosphate stranded helix. With the “base backbone complementarity,” it explains genetic material: (phosphodiester • Storage of genetic information bonds) • Replication • Information retrival IntroductionCentral to Cells Dogma & Microscopy of Molecular Biology From DNA to Protein: Gene Expression • Central Dogma: from Genes to Proteins • Replication of the genes (DNADNA) • Transcribing the information (DNARNA) • Translating the nucleotide sequence into protein sequence (RNAProtein) – The Genetic Code – Protein Biosynthesis Central Dogma The central dogma of molecular biology Replication Information Flow Replication DNA replication is semiconservative (Meselson-Stahl Expt) DNA Replication Arthur Kornberg showed that DNA contains information for its own replication. He combined in a test tube: DNA, the four deoxyribonucleoside triphosphates (dNTPs–monomers), DNA polymerase, salts (Mg+2), and buffer. The DNA served as a template for synthesis of new DNA. Each New DNA Strand Grows from Its 5´ End to Its 3´ End Each New DNA Strand Grows from Its 5´ End to Its 3´ End ALL polymerases add nucleotides to the 3’ end (Direction is termed 5’ 3’) Pyrophosphatase 34 Transcription Central Dogma The central dogma of molecular biology Replication Messenger RNA (mRNA) Transfer RNA (tRNA) Ribosomal RNA (rRNA) • What is the relationship between a DNA sequence and an amino acid sequence? Central Dogma RNA is key to this process: • Messenger RNA (mRNA)—carries copy of a DNA sequence to site of protein synthesis at the ribosome • Transfer RNA (tRNA)—carries amino acids for polypeptide assembly • Ribosomal RNA (rRNA)—catalyzes peptide bond formation and provides structure for the ribosome Transcription Transcription components: • A DNA template for base pairings—one of the two strands of DNA • Nucleoside triphosphates (ATP,GTP,CTP,UTP) as substrates • An RNA polymerase enzyme Transcription process: • RNA polymerase unwinds DNA about ten base pairs at a time; reads template in 3’ to 5’ direction, synthesizes RNA in the 5’ to 3’ direction. • The RNA transcript is antiparallel to the DNA template strand, and adds nucleotides to its 3’ end. • NTPs incorporate NMP and PPi is a product! Transcription • Production of mRNA transcript by RNA polymerase Transcription: Where to start? 5' FlankingCoding Region 3'-flanking prokaryotes Promoter eukaryotes The consensus sequence for each element in human genes (N is any nucleotide) Transcription Translation Central Dogma The central dogma of molecular biology Replication Messenger RNA (mRNA) Transfer RNA (tRNA) Ribosomal RNA (rRNA) • What is the relationship between a DNA sequence and an amino acid sequence? • The Code • The Adaptors (tRNA) • The Ribosome (rRNA + rProteins) Translation: The Genetic Code The genetic code: Specifies which amino acids will be used to build a protein Codon: A sequence of three bases—each codon specifies a particular amino acid. Start codon: AUG—initiation signal for translation. Stop codons: UAA, UAG, UGA—stop translation and polypeptide is released. Translation: The Genetic Code The genetic code is redundant. The genetic code is universal. Translation: tRNA tRNAs must deliver amino acids corresponding to each codon The conformation (three-dimensional shape) of tRNA results from base pairing (hydrogen bonding) within the molecule. 3‘-end is the amino-acid attachment site—binds covalently. At the other end (middle of the tRNA sequence) is the Anticodon—site of base pairing with mRNA. Unique for each species of tRNA. Translation: tRNA Translation: tRNA Template for mRNA – read 3’5’ tRNA anticodon NC Translation: Ribosome Ribosome: the workbench—holds mRNA and charged tRNAs in the correct positions to allow assembly of polypeptide chain. Ribosomes are not specific, they can make any type of protein. Translation: Protein Biosynthesis: Ribosome Structure Ribosomes have two subunits, large and small. When not active in translation, the subunits exist separately. • The small subunit (40S) has one ribosomal RNA (rRNA) (18S) and 33 proteins. • The large subunit (60S) has three molecules of rRNA (28S, 5.8S, 5S) and 49 different proteins. • Ribosomal subunits are held together by ionic and hydrophobic forces (not covalent bonds) (80S). Translation: Ribosome Translation: Protein Biosynthesis; Elongation EF-Tu GTP Decoding (GTP hydrolysis) Peptidyltransferase Translation: Protein Biosynthesis; Elongation ELONGATION Translocation (GTP hydrolysis) Central Dogma The central dogma of molecular biology Replication Animated videos of DNA structure and Central Dogma.
Load more

Recommended publications
  • Nucleotide Degradation
    Nucleotide Degradation Nucleotide Degradation The Digestion Pathway • Ingestion of food always includes nucleic acids. • As you know from BI 421, the low pH of the stomach does not affect the polymer. • In the duodenum, zymogens are converted to nucleases and the nucleotides are converted to nucleosides by non-specific phosphatases or nucleotidases. nucleases • Only the non-ionic nucleosides are taken & phospho- diesterases up in the villi of the small intestine. Duodenum Non-specific phosphatases • In the cell, the first step is the release of nucleosides) the ribose sugar, most effectively done by a non-specific nucleoside phosphorylase to give ribose 1-phosphate (Rib1P) and the free bases. • Most ingested nucleic acids are degraded to Rib1P, purines, and pyrimidines. 1 Nucleotide Degradation: Overview Fate of Nucleic Acids: Once broken down to the nitrogenous bases they are either: Nucleotides 1. Salvaged for recycling into new nucleic acids (most cells; from internal, Pi not ingested, nucleic Nucleosides acids). Purine Nucleoside Pi aD-Rib 1-P (or Rib) 2. Oxidized (primarily in the Phosphorylase & intestine and liver) by first aD-dRib 1-P (or dRib) converting to nucleosides, Bases then to –Uric Acid (purines) –Acetyl-CoA & Purine & Pyrimidine Oxidation succinyl-CoA Salvage Pathway (pyrimidines) The Salvage Pathways are in competition with the de novo biosynthetic pathways, and are both ANABOLISM Nucleotide Degradation Catabolism of Purines Nucleotides: Nucleosides: Bases: 1. Dephosphorylation (via 5’-nucleotidase) 2. Deamination and hydrolysis of ribose lead to production of xanthine. 3. Hypoxanthine and xanthine are then oxidized into uric acid by xanthine oxidase. Spiders and other arachnids lack xanthine oxidase.
    [Show full text]
  • Chapter 23 Nucleic Acids
    7-9/99 Neuman Chapter 23 Chapter 23 Nucleic Acids from Organic Chemistry by Robert C. Neuman, Jr. Professor of Chemistry, emeritus University of California, Riverside [email protected] <http://web.chem.ucsb.edu/~neuman/orgchembyneuman/> Chapter Outline of the Book ************************************************************************************** I. Foundations 1. Organic Molecules and Chemical Bonding 2. Alkanes and Cycloalkanes 3. Haloalkanes, Alcohols, Ethers, and Amines 4. Stereochemistry 5. Organic Spectrometry II. Reactions, Mechanisms, Multiple Bonds 6. Organic Reactions *(Not yet Posted) 7. Reactions of Haloalkanes, Alcohols, and Amines. Nucleophilic Substitution 8. Alkenes and Alkynes 9. Formation of Alkenes and Alkynes. Elimination Reactions 10. Alkenes and Alkynes. Addition Reactions 11. Free Radical Addition and Substitution Reactions III. Conjugation, Electronic Effects, Carbonyl Groups 12. Conjugated and Aromatic Molecules 13. Carbonyl Compounds. Ketones, Aldehydes, and Carboxylic Acids 14. Substituent Effects 15. Carbonyl Compounds. Esters, Amides, and Related Molecules IV. Carbonyl and Pericyclic Reactions and Mechanisms 16. Carbonyl Compounds. Addition and Substitution Reactions 17. Oxidation and Reduction Reactions 18. Reactions of Enolate Ions and Enols 19. Cyclization and Pericyclic Reactions *(Not yet Posted) V. Bioorganic Compounds 20. Carbohydrates 21. Lipids 22. Peptides, Proteins, and α−Amino Acids 23. Nucleic Acids **************************************************************************************
    [Show full text]
  • Alternative Biochemistries for Alien Life: Basic Concepts and Requirements for the Design of a Robust Biocontainment System in Genetic Isolation
    G C A T T A C G G C A T genes Review Alternative Biochemistries for Alien Life: Basic Concepts and Requirements for the Design of a Robust Biocontainment System in Genetic Isolation Christian Diwo 1 and Nediljko Budisa 1,2,* 1 Institut für Chemie, Technische Universität Berlin Müller-Breslau-Straße 10, 10623 Berlin, Germany; [email protected] 2 Department of Chemistry, University of Manitoba, 144 Dysart Rd, 360 Parker Building, Winnipeg, MB R3T 2N2, Canada * Correspondence: [email protected] or [email protected]; Tel.: +49-30-314-28821 or +1-204-474-9178 Received: 27 November 2018; Accepted: 21 December 2018; Published: 28 December 2018 Abstract: The universal genetic code, which is the foundation of cellular organization for almost all organisms, has fostered the exchange of genetic information from very different paths of evolution. The result of this communication network of potentially beneficial traits can be observed as modern biodiversity. Today, the genetic modification techniques of synthetic biology allow for the design of specialized organisms and their employment as tools, creating an artificial biodiversity based on the same universal genetic code. As there is no natural barrier towards the proliferation of genetic information which confers an advantage for a certain species, the naturally evolved genetic pool could be irreversibly altered if modified genetic information is exchanged. We argue that an alien genetic code which is incompatible with nature is likely to assure the inhibition of all mechanisms of genetic information transfer in an open environment. The two conceivable routes to synthetic life are either de novo cellular design or the successive alienation of a complex biological organism through laboratory evolution.
    [Show full text]
  • An O(N5) Algorithm for MFE Prediction of Kissing Hairpins and 4-Chains in Nucleic Acids
    JOURNAL OF COMPUTATIONAL BIOLOGY Volume 16, Number 6, 2009 # Mary Ann Liebert, Inc. Pp. 803–815 DOI: 10.1089/cmb.2008.0219 An O(n5) Algorithm for MFE Prediction of Kissing Hairpins and 4-Chains in Nucleic Acids HO-LIN CHEN,1 ANNE CONDON,2 and HOSNA JABBARI2 ABSTRACT Efficient methods for prediction of minimum free energy (MFE) nucleic secondary struc- tures are widely used, both to better understand structure and function of biological RNAs and to design novel nano-structures. Here, we present a new algorithm for MFE secondary structure prediction, which significantly expands the class of structures that can be handled in O(n5) time. Our algorithm can handle H-type pseudoknotted structures, kissing hairpins, and chains of four overlapping stems, as well as nested substructures of these types. Key words: kissing hairpins, pseudoknot, RNA, secondary structure prediction. 1. INTRODUCTION ur knowledge of the amazing variety of functions played by RNA molecules in the cell Ocontinues to expand, with the functions determined in part by structure (Lee et al., 1997). Additionally, DNA and RNA sequences are designed to form novel structures for a wide range of applications, such as algorithmic DNA self-assembly (He et al., 2008; Rothemund et al., 2004), detection of low concentrations of other molecules of interest (Dirks and Pierce, 2004) or to exhibit motion (Simmel and Dittmer, 2005). In order to improve our ability to determine function from DNA or RNA sequences, and also to aid in the design of nucleic acids with novel structural or functional properties, accurate and efficient methods for predicting nucleic acid structure are very valuable.
    [Show full text]
  • Expanding the Genetic Code Lei Wang and Peter G
    Reviews P. G. Schultz and L. Wang Protein Science Expanding the Genetic Code Lei Wang and Peter G. Schultz* Keywords: amino acids · genetic code · protein chemistry Angewandte Chemie 34 2005 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim DOI: 10.1002/anie.200460627 Angew. Chem. Int. Ed. 2005, 44,34–66 Angewandte Protein Science Chemie Although chemists can synthesize virtually any small organic molecule, our From the Contents ability to rationally manipulate the structures of proteins is quite limited, despite their involvement in virtually every life process. For most proteins, 1. Introduction 35 modifications are largely restricted to substitutions among the common 20 2. Chemical Approaches 35 amino acids. Herein we describe recent advances that make it possible to add new building blocks to the genetic codes of both prokaryotic and 3. In Vitro Biosynthetic eukaryotic organisms. Over 30 novel amino acids have been genetically Approaches to Protein encoded in response to unique triplet and quadruplet codons including Mutagenesis 39 fluorescent, photoreactive, and redox-active amino acids, glycosylated 4. In Vivo Protein amino acids, and amino acids with keto, azido, acetylenic, and heavy-atom- Mutagenesis 43 containing side chains. By removing the limitations imposed by the existing 20 amino acid code, it should be possible to generate proteins and perhaps 5. An Expanded Code 46 entire organisms with new or enhanced properties. 6. Outlook 61 1. Introduction The genetic codes of all known organisms specify the same functional roles to amino acid residues in proteins. Selectivity 20 amino acid building blocks. These building blocks contain a depends on the number and reactivity (dependent on both limited number of functional groups including carboxylic steric and electronic factors) of a particular amino acid side acids and amides, a thiol and thiol ether, alcohols, basic chain.
    [Show full text]
  • Hexosamine Biosynthetic Pathway-Derived O-Glcnacylation Is Critical for RANKL-Mediated Osteoclast Differentiation
    International Journal of Molecular Sciences Article Hexosamine Biosynthetic Pathway-Derived O-GlcNAcylation Is Critical for RANKL-Mediated Osteoclast Differentiation Myoung Jun Kim 1,†, Hyuk Soon Kim 2,3,† , Sangyong Lee 1, Keun Young Min 1, Wahn Soo Choi 1,4 and Jueng Soo You 1,4,* 1 School of Medicine, Konkuk University, Seoul 05029, Korea; [email protected] (M.J.K.); [email protected] (S.L.); [email protected] (K.Y.M.); [email protected] (W.S.C.) 2 Department of Biomedical Sciences, College of Natural Science, Dong-A University, Busan 49315, Korea; [email protected] 3 Department of Health Sciences, The Graduate School of Dong-A University, Busan 49315, Korea 4 KU Open Innovation Center, Research Institute of Medical Science, Konkuk University, Chungju 27478, Korea * Correspondence: [email protected]; Tel.: +82-2-2049-6235 † The first two authors are equally contributed. Abstract: O-linked-N-acetylglucosaminylation (O-GlcNAcylation) performed by O-GlcNAc trans- ferase (OGT) is a nutrient-responsive post-translational modification (PTM) via the hexosamine biosynthetic pathway (HBP). Various transcription factors (TFs) are O-GlcNAcylated, affecting their activities and significantly contributing to cellular processes ranging from survival to cellular dif- ferentiation. Given the pleiotropic functions of O-GlcNAc modification, it has been studied in various fields; however, the role of O-GlcNAcylation during osteoclast differentiation remains to be explored. Kinetic transcriptome analysis during receptor activator of nuclear factor-kappaB (NF-κB) ligand (RANKL)-mediated osteoclast differentiation revealed that the nexus of major nutri- ent metabolism, HBP was critical for this process. We observed that the critical genes related to HBP Citation: Kim, M.J.; Kim, H.S.; activation, including Nagk, Gfpt1, and Ogt, were upregulated, while the global O-GlcNAcylation was Lee, S.; Min, K.Y.; Choi, W.S.; You, J.S.
    [Show full text]
  • Allopurinol Sodium) for Injection 500 Mg
    ALOPRIM® (allopurinol sodium) for Injection 500 mg [al'-ō-prĭm] For Intravenous Infusion Only Rx only DESCRIPTION: ALOPRIM (allopurinol sodium) for Injection is the brand name for allopurinol, a xanthine oxidase inhibitor. ALOPRIM (allopurinol sodium) for Injection is a sterile solution for intravenous infusion only. It is available in vials as the sterile lyophilized sodium salt of allopurinol equivalent to 500 mg of allopurinol. ALOPRIM (allopurinol sodium) for Injection contains no preservatives. The chemical name for allopurinol sodium is 1,5-dihydro-4H-pyrazolo[3,4-d]pyrimidin­ 4-one monosodium salt. It is a white amorphous mass with a molecular weight of 158.09 and molecular formula C5H3N4NaO. The structural formula is: The pKa of allopurinol sodium is 9.31. CLINICAL PHARMACOLOGY: Allopurinol acts on purine catabolism without disrupting the biosynthesis of purines. It reduces the production of uric acid by inhibiting the biochemical reactions immediately preceding its formation. The degree of this decrease is dose dependent. Allopurinol is a structural analogue of the natural purine base, hypoxanthine. It is an inhibitor of xanthine oxidase, the enzyme responsible for the conversion of hypoxanthine to xanthine and of xanthine to uric acid, the end product of purine metabolism in man. Allopurinol is metabolized to the corresponding xanthine analogue, oxypurinol (alloxanthine), which also is an inhibitor of xanthine oxidase. Reutilization of both hypoxanthine and xanthine for nucleotide and nucleic acid synthesis is markedly enhanced when their oxidations are inhibited by allopurinol and oxypurinol. This reutilization does not disrupt normal nucleic acid anabolism, however, because feedback inhibition is an integral part of purine biosynthesis.
    [Show full text]
  • 5 Inhibitors of Protein Synthesis
    5 Inhibitors of protein synthesis Many antimicrobial substances inhibit protein biosynthesis. In most cases the inhibition involved one or other of the events which take place on the ribosomes. Only a few agents inhibit either amino acid activation or the attachment of the activated amino acid to the terminal adenylic acid residue of transfer RNA (tRNA). There are many chemical types to be found among the inhibitors of prolein synthesis, a fa ct which has increased the difficulty of unders tanding the molecular nature of their inhibitory effects. Indeed, while the reaction which is inhibited has been ideIHified with some precision in certain instances, the nature of the molecular interaction between the sensitive site and inhibi tor remains generally elusive. The reason lies in the complexity of the reactions leading to the for mation of correctly sequenced polypeptides on the ribosome and also in the complex. ity of the structure of the ribosome itself. Our intention is to provide an outline of the current knowledge of the steps in protein biosynthesis. More detailed discussion is given to those specific reactions which are blocked by the inhibitors of protein biosynthesis. RIBOSOMES These remarkable organelles are the machines upon which polypeptides are elaborated. There are three main classes of ribosomes identified by their sedimentation coefficients. The 80S ribosomes are apparently confined to eukaryotic cells, while 70S ribosomes are found in both prokaryotic and euk aryotic cells. A unique species of50-55S ribosome found only in mamma· tian mitochondria resembles bacterial ribosomes in functional organization and antibiotic sensitivity. The 80S particle dissociates reversibly into 60S and 405 subunits and the 70S into 505 and 305 subunits as the Mg:2+ concentration of the solution is reduced.
    [Show full text]
  • Nucleotides and Nucleic Acids
    Nucleotides and Nucleic Acids Energy Currency in Metabolic Transactions Essential Chemical Links in Response of Cells to Hormones and Extracellular Stimuli Nucleotides Structural Component Some Enzyme Cofactors and Metabolic Intermediate Constituents of Nucleic Acids: DNA & RNA Basics about Nucleotides 1. Term Gene: A segment of a DNA molecule that contains the information required for the synthesis of a functional biological product, whether protein or RNA, is referred to as a gene. Nucleotides: Nucleotides have three characteristic components: (1) a nitrogenous (nitrogen-containing) base, (2) a pentose, and (3) a phosphate. The molecule without the phosphate groups is called a nucleoside. Oligonucleotide: A short nucleic acid is referred to as an oligonucleotide, usually contains 50 or fewer nucleotides. Polynucleotide: Polymers containing more than 50 nucleotides is usually referred to as polynucleotide. General structure of nucleotide, including a phosphate group, a pentose and a base unit (either Purine or Pyrimidine). Major purine and Pyrimidine bases of nucleic acid The roles of RNA and DNA DNA: a) Biological Information Storage, b) Biological Information Transmission RNA: a) Structural components of ribosomes and carry out the synthesis of proteins (Ribosomal RNAs: rRNA); b) Intermediaries, carry genetic information from gene to ribosomes (Messenger RNAs: mRNA); c) Adapter molecules that translate the information in mRNA to proteins (Transfer RNAs: tRNA); and a variety of RNAs with other special functions. 1 Both DNA and RNA contain two major purine bases, adenine (A) and guanine (G), and two major pyrimidines. In both DNA and RNA, one of the Pyrimidine is cytosine (C), but the second major pyrimidine is thymine (T) in DNA and uracil (U) in RNA.
    [Show full text]
  • Mechanisms of Synthesis of Purine Nucleotides in Heart Muscle Extracts
    Mechanisms of Synthesis of Purine Nucleotides in Heart Muscle Extracts David A. Goldthwait J Clin Invest. 1957;36(11):1572-1578. https://doi.org/10.1172/JCI103555. Research Article Find the latest version: https://jci.me/103555/pdf MECHANISMS OF SYNTHESIS OF PURINE NUCLEOTIDES IN HEART MUSCLE EXTRACTS1 BY DAVID A. GOLDTHWAIT2 (From the Departments of Biochemistry and Medicine, Western Reserve University, Cleveland, Ohio) (Submitted for publication February 18, 1957; accepted July 18, 1957) The key role of ATP, a purine nucleotide, in 4. Adenine or Hypoxanthine + PRPP -> AMP the conversion of chemical energy into mechanical or Inosinic Acid (IMP) + P-P. work by myocardial tissue is well established (1, The third mechanism of synthesis is through the 2). The requirement for purine nucleotides has phosphorylation of a purine nucleoside (8, 9): also been demonstrated in the multiple synthetic 5. Adenosine + ATP -, AMP + ADP. reactions which maintain all animal cells in the Several enzymatic mechanisms are known which steady state. Since the question immediately arises result in the degradation of purine nucleotides and whether the purine nucleotides are themselves in nucleosides. The deamination of adenylic acid is a steady state, in which their rates of synthesis well known (10): equal their rates of degradation, it seems reason- 6. AMP -* IMP + NH8. able to investigate first what mechanisms of syn- Non-specific phosphatases (11) as well as spe- thesis and degradation may be operative. cific 5'-nucleotidases (12) have been described At present, there are three known pathways for which result in dephosphorylation: the synthesis of purine nucleotides. The first is 7.
    [Show full text]
  • Biosynthesis of Ribosylthymine in the Transfer RNA of Streptococcus
    Proc. Nat. Acad. Sci. USA Vol. 72, No. 2, pp. 528-530, February 1975 Biosynthesis of Ribosylthymine in the Transfer RNA of Streptococcus faecalis: A Folate-Dependent Methylation Not Involving S-Adenosylmethionine (thymine/tRNA modification/formate/[methyl-'4Clmethionine/GlT'C-loop) ANN S. DELK AND JESSE C. RABINOWITZ Department of Biochemistry, University of California, Berkeley, Calif. 94720 Communicated by Bruce Ames, November 18, 1974 ABSTRACT Ribosylthymine is not present in tRNA of to produce thymidine 5'-monophosphate, which is sub- Streptococcus faecalis grown in the absence of folic acid, sequently used in DNA synthesis. Because of the folate although this methylated residue does occur in the tRNA of this organism when it is grown in the presence of folate. requirement for T formation in S. faecalis, it appeared possible We have found that, unlike other methylated residues in that methylation of RNA in this organism, particularly in RNA of S. faecalis and other organisms, the methyl moiety the biosynthesis of T, involves a folate derivative and not of ribosylthymine of the tRNA of folate-sufficient S. S-adenosylmethionine. faecalis is not derived from S-adenosylmethionine. Pre- liminary evidence suggests that a folate derivative serves MATERIALS AND METHODS as the methyl donor in this methylation. Unless stated otherwise, S. faecalis (ATCC 8043) and Esche- When grown in the presence of folic acid, Streptococcus richia coli (MRE 600) were grown for several generations in faecalis, like other prokaryotes, initiates protein synthesis
    [Show full text]
  • The Structure and Function of Large Biological Molecules 5
    The Structure and Function of Large Biological Molecules 5 Figure 5.1 Why is the structure of a protein important for its function? KEY CONCEPTS The Molecules of Life Given the rich complexity of life on Earth, it might surprise you that the most 5.1 Macromolecules are polymers, built from monomers important large molecules found in all living things—from bacteria to elephants— can be sorted into just four main classes: carbohydrates, lipids, proteins, and nucleic 5.2 Carbohydrates serve as fuel acids. On the molecular scale, members of three of these classes—carbohydrates, and building material proteins, and nucleic acids—are huge and are therefore called macromolecules. 5.3 Lipids are a diverse group of For example, a protein may consist of thousands of atoms that form a molecular hydrophobic molecules colossus with a mass well over 100,000 daltons. Considering the size and complexity 5.4 Proteins include a diversity of of macromolecules, it is noteworthy that biochemists have determined the detailed structures, resulting in a wide structure of so many of them. The image in Figure 5.1 is a molecular model of a range of functions protein called alcohol dehydrogenase, which breaks down alcohol in the body. 5.5 Nucleic acids store, transmit, The architecture of a large biological molecule plays an essential role in its and help express hereditary function. Like water and simple organic molecules, large biological molecules information exhibit unique emergent properties arising from the orderly arrangement of their 5.6 Genomics and proteomics have atoms. In this chapter, we’ll first consider how macromolecules are built.
    [Show full text]