Biomolecule Test

4 Key excerpts on "Biomolecule Test"

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  eBook - ePub

  Understanding Bioanalytical Chemistry

  Principles and Applications

  • Victor A. Gault, Neville H. McClenaghan(Authors)
  • 2013(Publication Date)
  • Wiley

    (Publisher)

  2

  Analysis and quantification of biomolecules

  The last chapter considered the main features and characteristics of important biomolecules. This chapter focuses on the core methods used to detect and measure these biomolecules in nature. Quantification of biomolecules lies at the heart of analysis of biological test samples. These samples are key to forensic investigation, clinical tests and research, and come from sources as diverse as soil to body fluids, hair and synthetic fibres. In order to quantify biomolecules within these samples it is necessary to apply a range of technologies, which vary from simple test procedures to analysis with complex state-of-the-art scientific instrumentation. As described, sensitivity, accuracy, and precision are vital in the determination and understanding of the role of individual biomolecules in nature.

  Learning Objectives

  • To appreciate the importance of accurate determination of biomolecules.
  • To outline the principles underlying major methods used to detect and quantify biomolecules.
  • To comprehend and apply knowledge of key parameters in the quantification of biomolecules.
  • To explain the principles of moles and molarity, and use related equations in basic calculations.
  • To distinguish between solubility and dilution, and their application in the preparation of solutions.

  2.1 Importance of accurate determination of biomolecules

  Without the ability to accurately determine the presence and amount of any given biomolecule in nature, we would not be able to understand the contribution and function of these important chemical entities. Since the first basic tests available to distinguish chemical elements, numerous methods have been developed to measure the amounts and types of large and small biomolecules. Individual biomolecules are principally distinguished on the basis of their chemical and physical properties, for example molecular mass

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  eBook - ePub

  Physical Biochemistry

  Principles and Applications

  • David Sheehan(Author)
  • 2013(Publication Date)
  • Wiley

    (Publisher)

  genome . This has emphasized the need to be able to study the highly-individual structures of biomacromolecules such as proteins to understand more fully their particular contribution to the biology of the cell. For the foreseeable future, these techniques are likely to impact to a greater or lesser extent on the activities of most life scientists. This text attempts to survey the main physical techniques and to describe how they can contribute to our knowledge of biological systems and processes. We will set the scene for this by first looking at the particular analytical problems posed by biomolecules.

  1.1 SPECIAL CHEMICAL REQUIREMENTS OF BIOMOLECULES

  The tens of thousands of biomolecules encountered in living cells may be classified into two general groups. Biomacromolecules (e.g. proteins; nucleic acids) are characterized by high molecular mass (denoted throughout this text as relative molecular mass, M r ) and are generally unstable under extreme chemical conditions where they may lose structure or break down into their chemical building blocks. Low molecular weight molecules are smaller and more chemically robust (e.g. amino acids; nucleotides; fatty acids). Within each group there is displayed a wide range of water-solubility, chemical composition and reactivity which is determined by complex interactions between physicochemical attributes of the biomolecule and solvent. These attributes are the main focus for the techniques described in this volume and reflect the highly individual function which each molecule performs in the cell (Tables 1.1 and 1.2 ).

  Notwithstanding the great range of form and structure, we can nonetheless recognize certain attributes as common to all biomolecules. The first and most obvious is that all of these molecules are produced in living cells under mild chemical conditions of temperature, pressure and pH. Biomacromolecules are built up from simpler building block molecules by covalent bonds formed usually with the elimination of water. Moreover, biomolecules are continuously synthesized and degraded

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  eBook - ePub

  Bioanalytical Chemistry

  • Andreas Manz, Petra S Dittrich, Nicole Pamme, Dimitri Iossifidis(Authors)
  • 2015(Publication Date)
  • ICP

    (Publisher)

  Three-dimensional structures of both proteins and nucleic acids can be obtained by sophisticated NMR-experiments, by electron microscopy, and by X-ray crystallography, if a monocrystal can be obtained. These techniques are not covered in this textbook. The interested reader can refer to one of the textbooks in the references given at the end of this chapter.

  1.3.3.3.Systems biology

  Nowadays, (bio)analytical chemistry refers not only to the identification of molecules and the elucidation of their structure. Bioanalytical chemistry is used in the wide context of analytical challenges across the life sciences and medicine. Moreover, the paradigm shifts of the past decade have resulted in new analytical concepts, and biomolecules are not any more seen as an isolated target that has to be separated and analysed. Instead, the function and role of biomolecules have to be studied in the context of living biological systems. Hence, these biological systems — cells, organs and tissue, organisms — have to be investigated in their entire complexity and depth without isolation of the individual compartments and biomolecules. This will finally reveal new insights into cellular processes, e.g. entire metabolic pathways or cell signalling pathways, and allow, at the same time, theoretical description of the cellular networks with their individual biochemical processes. To face these challenges, interdisciplinary research consortia are formed between analytical chemists, biologists, computer scientists and many more.

  Fig. 1.28.A cell — here an eukaryotic cell — is the smallest “unit” of life. All biomolecules and subcompartments — the organelles — are kept together by the plasma membrane. Only this compartmentalisation together with the required composition of biomolecules ensures that all essential biochemical processes are conducted in the right way and that the cell can live, grow and divide. Systems biology is the approach to understand this complex cell machinery.

  Summary The structure and main features of amino acids, proteins and nucleotides and DNA were outlined in this chapter.

  DNA is the hereditary molecule of all cellular life forms. It stores and transmits genetic information. DNA is a relatively simple molecule, composed only of four different nucleotides with the bases adenine, guanine, thymine and cytosine and β -D-deoxyribose as the sugar component. Millions of nucleotides can be linked together. Two complementary strands are twisted around each other in the form of a double helix. They are held together by hydrogen bonds between the base pairs adenine-thymine and cytosine-guanine. RNA is comprised of nucleotides with the bases adenine, guanine, uracil and cytosine and β

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  eBook - ePub

  Biophysical Chemistry

  • Alan Cooper(Author)
  • 2015(Publication Date)
  • Royal Society of Chemistry

    (Publisher)

  1

  Biological Molecules

  You don’t need to know any biology in order to study biological molecules, but it does help to have some background.

  Aims This chapter will briefly review the bare bones of biological (macro)molecules. By the end, and together with your previous knowledge and some background reading, you should be able to:

  • Describe the basic chemical structures of polypeptides, polynucleotides, fats, lipids, and carbohydrates
  • Explain what is meant by the primary, secondary, tertiary and quaternary structure of proteins
  • Describe the behaviour of fats, lipids and detergents in water
  • Explain the anomalous properties of liquid water
  • Recall the fundamentals of acid–base equilibrium

  1.1 Introduction

  This book is mainly about the experimental methods used to understand the physical properties and function of the molecules that make up living systems.

  These molecules—proteins, polynucleotides, polysaccharides, lipids—are not necessarily any different from molecules we study in other branches of chemistry. But there are some additional factors, arising from their biological origin, which we need to be aware of.

  • Biological macromolecules are large molecules formed from many smaller units and are (usually) polymers of precise length and specific sequence.
  • They (usually) fold or associate into specific conformational assemblies stabilized by non-covalent interactions.
  • This (usually) happens in water.
  • The molecules are the (usually) successful outcomes of biological evolution.

  It is this last point that makes things so exciting for the biophysical chemist. The molecules we see today are the results of countless random (more or less) experiments over millions of years during which living systems have evolved to take advantage of subtle principles of physical chemistry that we barely yet understand. By studying such systems we can learn much about physical chemistry in general, with potential for applications in other areas.

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