Basic Sciences for Dental Students

Simon A. Whawell, Daniel W. Lambert, Simon A. Whawell, Daniel W. Lambert

• Publisher: Wiley-Blackwell
• Year: 2017
• ISBN:
  9781118906088
• Edition: 1
• Topic: Médecine
• Subtopic: Dentisterie

The ' all-in-one' solution to mastering basic sciences in preclinical dentistry

Basic Sciences for Dental Students is a cutting edge textbook specifically designed to support the needs of early years undergraduate dental students. Written by leaders in dental education and active oral and dental researchers involved with student assessment, the text explains the basic science that underpins the dental curriculum in undergraduate dental courses worldwide.

Specifically related to dentistry and future clinical practice, chapters cover all of the introductory subjects that students need to know – biomolecules, cell biology, tissues of the body, cardiovascular, circulatory and pulmonary systems, the nervous system, immunology, oral microbiology, pathology, head and neck anatomy, tooth development, craniofacial development, saliva, and dental materials.

Key features:

• Provides the basic science that underpins the early years of a dental curriculum
• Specifically tailored towards dentistry and future clinical practice
• Written by leaders in dental education and active oral and dental researchers
• Includes learning objectives and clinical relevance boxes throughout
• Self-assessment questions and downloadable figures are hosted on a companion website

Basic Sciences for Dental Students is an indispensable resource for undergraduate dental students, especially those in the early years of their studies. It is also a useful revision tool for postgraduate MJDF and MFDS examinations and overseas candidates sitting their OREs.

1
Biomolecules

Daniel W. Lambert and Simon A. Whawell

School of Clinical Dentistry, University of Sheffield, Sheffield, UK

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Learning Objectives

• To understand the basis of molecular structure and bonding.
• To outline the basic structure and function of proteins, carbohydrates, lipids and nucleic acids.
• To be able to describe the biological role of enzymes and explain how their activity is regulated.
• To understand basic energy‐yielding pathways and how they are controlled.

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Clinical Relevance

An understanding of basic biomolecule structure and function provides a foundation for all normal cell and tissue structure and physiology. The structure of biomolecules present in the human body closely relates to their function, as is the case for cells and tissues. In disease, drugs can be used that target specific biochemical pathways, so an appreciation of biochemistry underlies patient care as well as the diagnosis, prognosis and treatment of disease.

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Introduction

As complex as the human body is, it is heavily dependent on just four atoms for its composition: carbon, hydrogen, nitrogen and oxygen. These atoms form structurally diverse groups of biologically important molecules, their structure always relating to their function in the same way that the cells and tissues of the body are adapted. Biomolecules commonly take part in relatively simple reactions which are subject to complex control to finely tune the essential processes that they mediate. Biomolecules are often large polymers made up from smaller molecular monomers and even though there are thousands of molecules in a cell there are relatively few major biomolecule classes. Fatty acids, monosaccharides, amino acids and nucleotides form di‐ and triglycerides, polysaccharides, proteins and nucleic acids respectively. Small molecules are also important to biology, as we will see; adenosine triphosphate (ATP), for example, stores energy for catabolic and anabolic process and nicotinamide adenine dinucleotide (NADH) is the principle electron donor in the respiratory electron transport chain.

Biological Bonding

Molecular bonds are dependent on the arrangement of electrons in the outermost shell of each atom, being most stable when this is full. This can be achieved by transferring electrons, which takes place in ionic bonding (e.g. NaCl) or by sharing electrons in a covalent bond. Biological systems are also crucially dependent on non‐covalent bonds, namely hydrogen bonds (or H bonds), electrostatic interactions and van der Waals’ forces. While these ‘bonds’ are associated with at least an order of magnitude lower energy than covalent bonds they are collectively strong and can have significant influence on biological reactions. Non‐covalent bonds differ in their geometry, strength and specificity. Hydrogen bonds are the strongest and form when hydrogen that is covalently linked to an electronegative atom such as oxygen or nitrogen has an attractive interaction with another electronegative atom. They are highly directional and are strongest when the atoms involved are co‐linear. Hydrogen bonds are important in the stabilization of biomolecules such as DNA and in the secondary structure of proteins. Charged groups within biomolecules can be electrostatically attracted to each other. Amino acids, as we will discuss later, can be charged and such electrostatic interactions are important in enzyme–substrate interactions. The presence of competing charged ions such as those in salt would weaken such interactions. Finally, the weakest of the non‐covalent interactions is the non‐specific attraction called the van der Waals’ force. This results from transient asymmetry of charge distribution around a molecule which, by encouraging such asymmetry in surrounding molecules, results in an attractive interaction. Such forces only come into play when molecules are in close proximity and although weak can be of significance when a number of them form simultaneously.

Water, Water Everywhere

The human body is of course comprised mostly of water but it is worth mentioning the profound effects that water has on biological interactions. Two properties of water are particularly important in this regard, namely its polar nature and cohesion. A water molecule has a triangular shape and the polarity comes from the partial positive charge exhibited by the hydrogen atom and the partial negative charge of the oxygen. The cohesive properties of water are due to the presence of hydrogen bonding (Figure 1.1). Water is an excellent solvent for polar molecules and does this by weakening/competing for hydrogen bonds and electrostatic interactions. In biology, water‐free microenvironments must be created for polar interactions to have maximum strength.

Figure 1.1 The chemical structure of water.

Amino Acids and Proteins

Proteins are polymers of amino acids and are the most abundant and structurally and functionally diverse group of biomolecules. They form structural elements within the cell and extracellular matrix, act as transport and signalling molecules, interact to enable muscles to contract and form the biological catalysts (enzymes) without which most c...

Table of contents

• Cover
• Title Page
• Table of Contents
• List of Contributors
• About the Companion Website
• 1 Biomolecules
• 2 Cell Biology
• 3 Tissues of the Body
• 4 The Cardiovascular, Circulatory and Pulmonary Systems
• 5 The Nervous System
• 6 Introduction to Immunology
• 7 Oral Microbiology
• 8 Introduction to Pathology
• 9 Head and Neck Anatomy
• 10 Tooth Development, Tooth Morphology and Tooth‐Supporting Structures
• 11 Craniofacial Development
• 12 Saliva and Salivary Glands
• 13 Introduction to Dental Materials
• Index
• End User License Agreement