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Chapter

Cover Pharmaceutical Chemistry

Nucleic Acids  

Alex White and Andrew Evans

This chapter discusses the varied roles of molecules and the classes of cells that form the basis of all life. It presents information on the basic structure and functions of cells and considers the molecules involved in their structure and function. The chapter outlines the chemistry of nucleic acids, which are larger than most molecules and are often referred to as macromolecules. It then reviews the principles of chemistry that can be applied to the study of these molecules to help understand their functions in the cells of a human body. In addition, the involvement of nucleic acids in the genetic code is explored. The chapter covers how it is stored, used, protected, repaired, and passed from generation to generation.

Chapter

Cover Human Virology

General properties of viruses  

This chapter describes viruses as small organisms that retain infectivity after passage through filters small enough to hold back bacteria. Bacteria are measured in terms of the micrometre (μm), which is 10-6 of a metre. For viruses, the nanometre (nm) is used as the unit, which is a thousand times smaller. The chapter points out that viruses are totally dependent on living cells, either eukaryotic or prokaryotic, for their replication and existence, and possess and carry enzymes of their own. Viruses cannot reproduce and amplify and translate into proteins the information in their genomes without the assistance of the cellular architecture and protein translation machinery, namely ribosomes. The chapter discusses viruses that possess only one species of nucleic acid, either DNA or RNA, and have a component for attaching or ‘docking’ to cells so that they can commandeer the cells as virus production factories.

Chapter

Cover Pharmaceutical Chemistry

Proteins and Enzymes  

Alex White and Helen Burrell

This chapter talks about proteins. These make up a highly important class of macromolecules in biochemistry and are considered to be biopolymers constructed from amino acid monomers. Compared with nucleic acids, proteins have varied and complex three-dimensional structures, due in part to the greater variety of monomers used to construct them. The chapter describes the unique three-dimensional structure of protein which is directly related to the function it performs. The chapter covers the detail of the structures, citing a myriad of functions in cells and organelles, such as antibodies, collagen, membrane-bound receptors, and enzymes. Enzymes and receptors are of particular importance to pharmacy as many drugs interact with them to bring about their therapeutic activity.

Chapter

Cover An Introduction to Medicinal Chemistry

Nucleic acids: structure and function  

This chapter talks about the structure and function of nucleic acids, citing examples of important drugs that act directly on nucleic acids. It describes two types of nucleic acid: DNA (deoxyribonucleic acid) and RNA (ribonucleic acid). It also examines the primary structure of DNA which consists of a sugar–phosphate backbone with nucleic acid bases attached to each sugar moiety. The chapter highlights how the DNA double helix is coiled up into a tertiary structure, analyzing the coiling and uncoiling of the double helix that require topoisomerase enzymes. It looks at the genetic code that consists of nucleic acid bases, which are read in sets of three during the synthesis of a protein.

Chapter

Cover Foundations of Chemical Biology

Geneticinformation: nucleotides and nucleic acids  

This chapter discusses the nature of nucleotides and the polymers that derive from nucleotides called nucleic acids, demonstrating how they fold into ordered structures and give rise to the spontaneous assembly of lipids into membranes. It illustrates the structural features of nucleic acids that are exploited in their role as information stores. It also outlines cells as complex entities and localized capsules of chemicals that can reproduce to generate new cells of a near-identical nature. The chapter highlights that the nature of a particular cell depends on the array of chemicals within the cell and the nature of their interconversion. It analyses how proteins are involved in all activities of the cell, such as the uptake and transport of small molecules and the catalysis of chemical reactions.

Chapter

Cover Elements of Physical Chemistry

Biological and synthetic macromolecules  

This chapter describes macromolecules that adopt shapes governed by molecular interactions, including van der Waals interactions, hydrogen bonding, and the hydrophobic effect. It considers a range of structures, beginning with a structureless random coil and then progressing to the structurally precise proteins and nucleic acids. It also covers the mechanical and thermal properties of macromolecules. The chapter demonstrates how to describe the structural features of macromolecules in order to understand their physical, chemical, and mechanical properties. It analyzes the structure of a macromolecule that takes on different meanings at the different levels at which the arrangement of the chain or network of its building blocks are considered.

Chapter

Cover An Introduction to Medicinal Chemistry

The design of oxamniquine  

This chapter explores the development of oxamniquine by Pfizer pharmaceuticals, which the chapter uses as an example of how traditional strategies can be used in the development of a drug where the molecular target is unknown. It describes oxamniquine as an important drug in developing countries. This drug is used in the treatment of schistosomiasis. After malaria, schistosomiasis is the most endemic parasitic disease in the world, affecting about 236 million people in 78 countries and causing up to 200,000 deaths each year. The chapter highlights the effectivity of oxamniquine as a single oral dose for treating infections of S. mansoni. Oxamniquine is known to inhibit nucleic acid synthesis in schistosomal cells.

Chapter

Cover Biochemistry

Nucleic Acids  

This chapter analyses the nucleic acids DNA and RNA, which are polynucleotides that encode the genetic information used to construct and maintain living organisms. Double-stranded DNA is, in effect, the blueprint used to direct cell processes. The chapter highlights how cells convert DNA’s operating instructions into the nucleotide sequence of single-stranded RNA molecules. It outlines RNAs’ numerous functions, which include polypeptide synthesis, the regulation of gene expression, and protection from foreign nucleic acids introduced by viral infections. Investigations of nucleic acid structure and function, now almost 70 years old, have given humans a previously unimagined understanding of biological processes and a powerful tool used in such diverse fields as disease diagnosis and treatment and forensic investigations.

Chapter

Cover Biochemistry

Nitrogen Metabolism II: Degradation  

This chapter deals with the metabolism of nitrogen-containing molecules, such as proteins and nucleic acids, that differs significantly from that of carbohydrates and lipids. Whereas the latter molecules can be stored and mobilized when needed for biosynthetic reactions or for energy generation, there is no nitrogen-storing molecule. The chapter elaborates how organisms must constantly replenish their supply of usable nitrogen to replace organic nitrogen that is lost in catabolism. It mentions the turnover of protein and nucleic acids, which is one of the most obvious aspects of cellular renovation and is a process that results in the continuous flow of nitrogen atoms through living organisms. Living organisms recycle organic nitrogen into a variety of metabolites before the element is reconverted to its inorganic form.

Chapter

Cover Molecular Biology

Biological molecules  

This chapter reviews how molecules are built up by linking atoms together with covalent bonds and explores the way in which molecules interact with one another non-covalently in the aqueous environment of the cell. There are four major classes of biological molecules that play essential roles in all organisms: nucleotides, amino acids, carbohydrates, and lipids. Each of them can be found in cells both as individual small molecules or covalently linked to form larger molecules known as polymers or macromolecules. Nucleic acids are polymers of nucleotides that are responsible for carrying genetic information. Proteins, on the other hand, are polymers of amino acids that function as workhorses, carrying out most of the chemical reactions in the cell and giving cells their structure and shape. Many biological molecules can be covalently modified in ways that alter their chemical properties and allow their function to be regulated.

Chapter

Cover Biophysical Techniques

Biological molecules  

The aim of this tutorial is to remind readers about some of the molecules of life, their nomenclature and some of their properties. Nucleic acids are made from linear chains of nucleotides (Figure T1A). Phosphate groups bridge the 3’and 5’positions of...

Book

Cover Biochemistry
Biochemistry begins with an introduction to the topic. Discussions covered include living cells, the importance of water to life, energy, and amino acids, peptides, and proteins. The book also contains chapters on carbohydrates, carbohydrate metabolism, aerobic metabolism, and lipids and membranes. The text goes on to examine photosynthesis, nitrogen metabolism, nucleic acids, and genes. Finally, it looks at protein synthesis.

Chapter

Cover Chemistry for the Biosciences

Biological macromolecules: the infrastructure of life  

This chapter studies some of the key biological macromolecules that make life happen: amino acids and proteins, nucleic acids, carbohydrates, and lipids. Amino acids join together to form polymers named polypeptides. The structure of proteins is built up over four levels of hierarchy: primary, secondary, tertiary, and quaternary. Protein structure is stabilized by both non-covalent interactions (including hydrogen bonds and hydrophobic interactions) and covalent bonding, including disulfide bonds. The chapter also describes the two key natural nucleic acids, deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). Nucleic acids are polymers of nucleotides. The chapter then considers the three main classes of carbohydrate (sugar)—monosaccharides, disaccharides, and polysaccharides. It also looks at the three most important types of lipid: steroids, triacylglycerols, and the glycerophospholipids.

Chapter

Cover Plant Systematics

Taxonomic Evidence: Structural and Biochemical Characters  

The chapter focuses on taxonomic evidence consisting of the characters used in phylogenetic analyses. Plant classifications are based on this evidence, including characters used in describing patterns of variation at or below the species level. The chapter shows how taxonomic evidence can be gathered from a wide variety of sources, from all parts of a plant, and during all stages of a plant's development. It also summarizes the use of characters from morphology, anatomy, embryology, chromosomes, palynology, secondary metabolites, and proteins. The chapter also considers nucleic acids, namely DNA and RNA, as these are an increasingly important source of taxonomic characterization in plant taxonomy and the rapidly developing field of molecular systematics. The chapter also discusses morphological characters, which are used for practical plant identification and hypothesizing phylogenetic relationships.

Chapter

Cover Biochemistry

Carbohydrates: Why Life is Sweet  

This chapter describes the chemistry that underpins biomolecules, before considering the variety and flexibility of carbohydrates and their roles in living organisms. All biological cells are made up of common building blocks, or biomolecules, which carry out similar types of biochemical reactions. There are four types of these fundamental biomolecules: carbohydrates, proteins, lipids, and nucleic acids. Carbohydrates are the most abundant biomolecules on Earth and are characterized by great chemical and structural diversity. They are classified by size as monosaccharides, disaccharides, oligosaccharides, or polysaccharides. Carbohydrates are found in plant cell walls, the connective tissues of animals, and exoskeletons, and they are essential to the function of some proteins and cell-to-cell communication. They are also important fuels and energy stores, underpinning energy-yielding pathways in non-photosynthetic organisms.

Chapter

Cover Biochemistry

Nucleotides and Nucleic Acids: Biology’s Information Stores  

This chapter examines nucleotides and nucleic acids, which exist in all cells and have been widely studied. Nucleotides play a central role in supplying the energy for many metabolic reactions, and in the storage and use of genetic information: they are key players in passing on genetic material from one generation of cells to the next. They are also involved in controlling how genetic information is used. Meanwhile, nucleic acids are polymers of nucleotides. There are two types: ribonucleic acid (RNA) and deoxyribonucleic acid (DNA). As scientists' understanding of DNA and RNA molecules has developed, the era of molecular biology and, more recently, the era of synthetic biology, emerged. Genetic engineering and gene editing techniques allow the manipulation of genes into novel forms and are fundamental to biotechnology, where biological solutions are applied to some of the major challenges facing humanity.

Chapter

Cover Physical Chemistry for the Life Sciences

Macromolecular structure  

This chapter discusses the absence of structure: the shape a macromolecule would adopt if there were no organizing forces at work. As the shapes adopted by biological macromolecules are crucial to their function, the chapter reveals how intramolecular non-covalent interactions can lead to folding into specific shapes. To begin, the chapter considers random coils, in which the polymer can adopt any of the conformations that are consistent with its configuration while avoiding the steric repulsion that arises when atoms occupy the same region of space. Each polymer molecule in a random coil state in a sample might be in a different conformation, so the sample must be described as a statistical distribution over those conformations. Afterward, the chapter follows case studies based on three topics: oligosaccharides and polysaccharides, nucleic acids, and proteins.

Chapter

Cover Organic Chemistry

Chemistry of Biomolecules  

This chapter addresses some of the major constituents of our body: carbohydrates, nucleic acids, proteins, and lipids, and related compounds. It emphasizes that although structures of many biomolecules may be complicated, their chemistry is not especially difficult. The chapter notes that their reactions are governed by the principles of the chemistry of simple organic compounds. The chapter also introduces the kinds of compounds which play major roles in living systems, and identifies the molecular features which allow them to function in their biological roles. Finally, the chapter looks at fats and oils, and phospholipids. It then considers the nature of terpenes, steroids, and eicosanoids.

Chapter

Cover Molecular Biology of RNA

The short non-coding RNAs and gene silencing  

This chapter concentrates on a group of very important RNAs with critical roles in regulating gene expression, noting that the RNA molecules involved are much shorter. It explains why short RNA molecules have been co-opted into gene expression pathways, implying that they can be hybridized very selectively to target RNA sequences and act as an efficient targeting mechanism for directing protein components to nucleic acids. It also refers to protein components that carry out catalytic reactions that include the targeted destruction of RNA and the modification of chromatin. The chapter covers important and diverse roles in cells carried out by short ncRNAs, such as the siRNAs that generally target RNA for destruction and the microRNAs that generally regulate protein translation from mRNAs. The chapter describes the siRNAs that work like an intracellular immune system with the aim of incapacitating double-stranded (ds) RNAs that have invaded the cell.

Book

Cover Genetics in Medicine

Barbara Jennings, Nandu Thalange, and Gavin Willis

Genetics in Medicine examines nucleic acids, genes, and genomes. It also discusses mutations and genetic variations. Next, it considers laboratory techniques and the sequencing revolution. The application of genetic medicine in childhood is also taken into consideration. Then, the text examines genetic medicine for adult onset disease. The book ends with a discussion of pharmacogenetics and personalized medicine.