Catch Up Biology, second edition: For the Medical Sciences
By Philip Bradley and Jane Calvert
2.5/5
()
About this ebook
The book focuses on human biology and covers:
- the basic molecules of life, such as proteins, carbohydrates, nucleic acids
- cells, tissues and processes, including energy metabolism, cell division, epithelial and connective tissues
- the key mammalian systems, for example, homeostasis, the endocrine, respiratory and digestive systems.
Throughout the book the authors highlight clinical examples so that you can see the relevance of basic biology to your course. The book also contains questions (and answers) so that you can test your understanding of the subject as you work through the book. This new edition features two new chapters on microorganisms and on genetic disease.
Catch up Biology is the ideal book to refresh your understanding of the basic concepts of biology.
Related to Catch Up Biology, second edition
Related ebooks
Catch Up Chemistry, second edition: For the Life and Medical Sciences Rating: 5 out of 5 stars5/5Painless Biology Rating: 0 out of 5 stars0 ratingsBiology Super Review, 2nd. Ed. Rating: 0 out of 5 stars0 ratingsPractice Makes Perfect Biology Rating: 5 out of 5 stars5/5Basics of Biology Rating: 1 out of 5 stars1/5Biology Fundamentals Rating: 0 out of 5 stars0 ratingsA-level Biology Revision: Cheeky Revision Shortcuts Rating: 5 out of 5 stars5/5E-Z Microbiology Rating: 0 out of 5 stars0 ratingsIllustrated Notes on Biomolecules Rating: 0 out of 5 stars0 ratingsHigh School Biology: Comprehensive Content for Cell & Molecular Biology Rating: 0 out of 5 stars0 ratingsThe Molecules of Life: An Exploration of Biochemistry Rating: 0 out of 5 stars0 ratingsCell and Molecular Biology: An Introductory Guide for Learning Cellular & Molecular Biology Rating: 0 out of 5 stars0 ratingsMastering Biochemistry: A Comprehensive Guide to Excellence Rating: 0 out of 5 stars0 ratingsEssentials of Enzymology Rating: 0 out of 5 stars0 ratingsHow Life Works: The Inside Word from a Biochemist Rating: 0 out of 5 stars0 ratingsBiology Workbook For Dummies Rating: 0 out of 5 stars0 ratingsBiochemical Pathways: An Atlas of Biochemistry and Molecular Biology Rating: 4 out of 5 stars4/5Biophysical Chemistry Rating: 4 out of 5 stars4/5Introduction to the Human Cell: The Unit of Life & Disease Rating: 5 out of 5 stars5/5Molecular and Cell Biology For Dummies Rating: 4 out of 5 stars4/5Biology: A Self-Teaching Guide Rating: 5 out of 5 stars5/5Biochemistry For Dummies Rating: 5 out of 5 stars5/5Genetics For Dummies Rating: 4 out of 5 stars4/5Schaum's Outline of Genetics, Fifth Edition Rating: 4 out of 5 stars4/5Biochemistry Essentials Rating: 3 out of 5 stars3/5Schaum's Outline of Microbiology, Second Edition Rating: 5 out of 5 stars5/5Biology For Dummies Rating: 3 out of 5 stars3/5Genetics, revised edition: A Guide for Students and Practitioners of Nursing and Health Care Rating: 0 out of 5 stars0 ratingsSchaum's Outline of Biochemistry, Third Edition Rating: 0 out of 5 stars0 ratingsBiology Essentials For Dummies Rating: 0 out of 5 stars0 ratings
Biology For You
Why We Sleep: Unlocking the Power of Sleep and Dreams Rating: 4 out of 5 stars4/5The Source: The Secrets of the Universe, the Science of the Brain Rating: 4 out of 5 stars4/5Gut: The Inside Story of Our Body's Most Underrated Organ (Revised Edition) Rating: 4 out of 5 stars4/5The Soul of an Octopus: A Surprising Exploration into the Wonder of Consciousness Rating: 4 out of 5 stars4/5The Obesity Code: the bestselling guide to unlocking the secrets of weight loss Rating: 4 out of 5 stars4/5Peptide Protocols: Volume One Rating: 4 out of 5 stars4/5Sapiens: A Brief History of Humankind Rating: 4 out of 5 stars4/5Our Kind of People: Inside America's Black Upper Class Rating: 3 out of 5 stars3/5The Sixth Extinction: An Unnatural History Rating: 4 out of 5 stars4/5"Cause Unknown": The Epidemic of Sudden Deaths in 2021 & 2022 Rating: 5 out of 5 stars5/5Dopamine Detox: Biohacking Your Way To Better Focus, Greater Happiness, and Peak Performance Rating: 4 out of 5 stars4/5The Laws of Connection: The Scientific Secrets of Building a Strong Social Network Rating: 0 out of 5 stars0 ratingsHomo Deus: A Brief History of Tomorrow Rating: 4 out of 5 stars4/5Woman: An Intimate Geography Rating: 4 out of 5 stars4/5How Emotions Are Made: The Secret Life of the Brain Rating: 4 out of 5 stars4/5The Art of Thinking Clearly Rating: 4 out of 5 stars4/5Other Minds: The Octopus, the Sea, and the Deep Origins of Consciousness Rating: 4 out of 5 stars4/5The Winner Effect: The Neuroscience of Success and Failure Rating: 5 out of 5 stars5/5A Letter to Liberals: Censorship and COVID: An Attack on Science and American Ideals Rating: 3 out of 5 stars3/5Emotional Blackmail: When the People in Your Life Use Fear, Obligation, and Guilt to Manipulate You Rating: 4 out of 5 stars4/5Mothers Who Can't Love: A Healing Guide for Daughters Rating: 4 out of 5 stars4/5The Deepest Well: Healing the Long-Term Effects of Childhood Trauma and Adversity Rating: 4 out of 5 stars4/5The Grieving Brain: The Surprising Science of How We Learn from Love and Loss Rating: 4 out of 5 stars4/5The Rise and Fall of the Dinosaurs: A New History of a Lost World Rating: 4 out of 5 stars4/5Lifespan: Why We Age—and Why We Don't Have To Rating: 4 out of 5 stars4/5Suicidal: Why We Kill Ourselves Rating: 4 out of 5 stars4/5Lies My Gov't Told Me: And the Better Future Coming Rating: 4 out of 5 stars4/5
Reviews for Catch Up Biology, second edition
2 ratings0 reviews
Book preview
Catch Up Biology, second edition - Philip Bradley
© Scion Publishing Ltd, 2013
Second edition first published 2013
First edition published 2006, reprinted 2009, 2010, 2011, 2012
All rights reserved. No part of this book may be reproduced or transmitted, in any form or by any means, without permission.
A CIP catalogue record for this book is available from the British Library.
ISBN 978 1 904842 88 0
Scion Publishing Limited
The Old Hayloft, Vantage Business Park, Bloxham Rd, Banbury, OX16 9UX, UK
www.scionpublishing.com
Important Note from the Publisher
The information contained within this book was obtained by Scion Publishing Limited from sources believed by us to be reliable. However, while every effort has been made to ensure its accuracy, no responsibility for loss or injury whatsoever occasioned to any person acting or refraining from action as a result of information contained herein can be accepted by the authors or publishers.
Typeset by Phoenix Photosetting, Chatham, Kent, UK
Printed in the UK
Contents
Preface
Acknowledgements
01 Water and life
1.1 The properties of water
1.2 Water in the human body
1.3 Test yourself
02 Proteins
2.1 Introduction
2.2 Primary structure
2.3 Secondary structures
2.4 Tertiary structure
2.5 Quaternary structure
2.6 Domains
2.7 Functions of proteins
2.8 Conformational change
2.9 Test yourself
03 Carbohydrates
3.1 Introduction
3.2 Monosaccharides
3.3 Glycosidic bond
3.4 Polysaccharides
3.5 Glycoconjugates
3.6 Functions of carbohydrates
3.7 Test yourself
04 Lipids
4.1 Introduction
4.2 Fatty acids
4.3 Triglycerides and phospholipids
4.4 Cholesterol
4.5 Functions of lipids
4.6 Test yourself
05 Nucleic acids and genes
5.1 Introduction
5.2 DNA and RNA
5.3 DNA synthesis
5.4 RNA synthesis
5.5 The genetic code
5.6 Protein synthesis
5.7 Introns and exons
5.8 Regulation of gene expression
5.9 Test yourself
06 The cell
6.1 Introduction
6.2 Eukaryotic cells
6.3 Cell specialisation
6.4 Test yourself
07 Microorganisms
7.1 Introduction
7.2 Bacteria
7.3 Viruses
7.4 Fungi
7.5 Other infectious agents
7.6 Treatment of infectious disease
7.7 Test yourself
08 Energy metabolism
8.1 Introduction
8.2 The citric acid cycle
8.3 Release of energy from fats and proteins
8.4 Oxidative phosphorylation
8.5 Anaerobic respiration
8.6 Test yourself
09 Membrane transport
9.1 Introduction
9.2 Osmosis
9.3 Facilitated diffusion
9.4 Active transport
9.5 Exocytosis and endocytosis
9.6 Test yourself
10 Cell division and mitosis
10.1 Introduction
10.2 Cell cycle
10.3 Control of cell division
10.4 Cell division and differentiation
10.5 Test yourself
11 Reproduction
11.1 Introduction
11.2 Sexual reproduction
11.3 Fertilisation
11.4 Reproductive and therapeutic cloning
11.5 Test yourself
12 Inheritance
12.1 Introduction
12.2 Definition of terms
12.3 Mutations
12.4 Mendelian inheritance
12.5 Monohybrid inheritance
12.6 Dihybrid inheritance
12.7 Linkage
12.8 Autosomal and sex-linked genes
12.9 Genetic fingerprinting
12.10 Evolution by natural selection
12.11 Test yourself
13 Genetic disease
13.1 Introduction
13.2 Cystic fibrosis: an autosomal recessive disease
13.3 Huntington disease: an autosomal dominant disease
13.4 Haemophilia A: an X-linked recessive disease
13.5 Asthma: a disease caused by multiple genes
13.6 Genetic testing
13.7 Gene therapy and genetic diseases
13.8 Test yourself
14 Epithelial tissues
14.1 Introduction
14.2 Classification
14.3 Adhesion
14.4 Test yourself
15 Connective tissues
15.1 Introduction
15.2 Glycosaminoglycans
15.3 Fibres
15.4 Cells
15.5 Test yourself
16 Excitable tissues
16.1 Introduction
16.2 Membrane potential
16.3 Muscle
16.4 Nerve
16.5 Test yourself
17 Homeostasis
17.1 Introduction
17.2 Regulation of plasma glucose
17.3 Thermoregulation
17.4 Test yourself
18 The endocrine system
18.1 Introduction
18.2 Types of hormone
18.3 Cell signal receptors
18.4 Second messenger systems
18.5 Endocrine glands
18.6 Hypothalamo-pituitary axis
18.7 Posterior pituitary
18.8 Other endocrine glands
18.9 Test yourself
19 The nervous system
19.1 Introduction
19.2 Structure of nervous system
19.3 The brain
19.4 The spinal cord
19.5 Peripheral nervous system
19.6 Test yourself
20 The cardiovascular system
20.1 Introduction
20.2 Blood
20.3 Plasma
20.4 Red blood cells
20.5 Platelets
20.6 The heart
20.7 The circulatory system
20.8 Test yourself
21 The respiratory system
21.1 Introduction
21.2 Structure of the respiratory system
21.3 Respiration
21.4 Gaseous exchange
21.5 Control of respiration
21.6 Test yourself
22 The digestive system
22.1 Introduction
22.2 Oral cavity
22.3 Structure of the GI tube
22.4 The stomach
22.5 Small intestine and accessory glands
22.6 Large intestine
22.7 Test yourself
23 The reproductive system
23.1 Introduction
23.2 Male reproductive system
23.3 Spermatogenesis
23.4 Female reproductive system
23.5 Oogenesis and the menstrual cycle
23.6 Copulation and fertilisation
23.7 Implantation and pregnancy
23.8 Birth
23.9 Test yourself
24 The urinary system
24.1 The kidney
24.2 The bladder
24.3 Test yourself
25 The immune system
25.1 Immune responses to infection
25.2 Inflammation
25.3 Lymphocytes and the specific immune response
25.4 Diseases of the immune system
25.5 Test yourself
26 The musculoskeletal system
26.1 Introduction
26.2 Bone
26.3 Regulation of calcium levels
26.4 Cartilage
26.5 The skeleton
26.6 Synovial joints
26.7 Muscles and locomotion
26.8 Test yourself
Answers to 'test yourself' questions
Glossary
Index
Preface
Students entering university courses in the medical or biomedical sciences have a wide range of different qualifications and knowledge. Depending on the route of entry, different students will have covered topics in varying levels of detail. This short text aims to provide an overview of some of the important concepts that will help a student to understand and gain maximum benefit from their university course.
The book takes a hierarchical approach, starting with an introduction to the molecules of life, moving on to consider cells and their functions, how cells are assembled into tissues and ultimately the various systems of the body. Biology is a huge subject so this text selects material that will be most useful to students studying courses related to medicine and the medical sciences. In preparing this Second Edition we have listened to feedback from students and lecturers as to what additional topics would be useful and, as a result, we have included new material on genetic disease (Chapter 13) and have expanded the section on microorganisms to become a separate chapter (Chapter 7). There are a number of other updates in the text which reflect changing concepts regarding cellular organisation.
It is important to be aware of the position of humans in relation to other life on the planet. Life can be divided up into prokaryotes and eukaryotes, which differ markedly in the properties of their cells (Chapter 6). The prokaryotes include two major domains: the bacteria and the archaea, a detailed discussion of which is beyond the scope of this book. The eukaryotes can be divided into kingdoms, as shown in the diagram below.
Humans, of course, belong to the animal kingdom, but this contains many thousands of species and so we further classify humans as shown. Biological classification groups together organisms according to degrees of similarity and attempts to reflect evolutionary relationships. The material covered in the first part of the book is relevant to the whole of biology, because the molecules of life are, to a very large extent, shared across the kingdoms. As we go further into the book the material covered becomes more selective. Humans are mammals and, whilst the focus here is on human biology, most of the information covered will be true for other mammalian species.
Biology is a fascinating subject because it tells us how our bodies work and helps us to understand what can go wrong in disease. It is also a subject that has progressed in leaps and bounds as new technologies have allowed us to analyse the processes of life at ever more sophisticated levels. We hope that you will continue to be excited by this science and share your enthusiasm with others.
Philip Bradley and Jane Calvert
March 2013
Acknowledgements
We would like to thank all those who have helped and advised in relation to the material in this book, including both reviewers and our academic colleagues. Most particularly, we would like to thank Austin Diamond and Monica Hughes for their comments on sections of the book. We would also like to thank Julie Alexander for her patient help and support.
Most of all we are grateful to all our many students over the years who have taught us far more than we taught them.
01
Water and life
Basic concepts:
Water makes up approximately 60% of the human body. Its molecular structure allows it to act as a solvent for many of the other key molecules which enable cells to function and life to be maintained. An understanding of the distribution of water in the body, the composition of the various fluid compartments and the control of the movement of water between compartments is crucial to understanding many basic life processes.
1.1 The properties of water
Water is essential for life. The cells of living organisms are composed of around 70% water and many of the reactions essential to life occur in an aqueous environment. The chemical properties of water make it a particularly suitable medium for supporting life. Water is a polar molecule, which is to say it has an uneven distribution of charge (Fig. 1.1).
Figure 1.1. A water molecule showing distribution of charge
This means that it is able to interact with other polar and charged groups. Molecules or groups that interact with water are described as hydrophilic, whereas non-polar groups are described as hydrophobic.
Virtually all the molecules of life are based around the element carbon. These include:
sugars and polysaccharides
amino acids and proteins
nucleotides and nucleic acids
lipids
Polysaccharides, proteins and nucleic acids are very large molecules, termed macromolecules, and are polymers of sugars, amino acids and nucleotides respectively. Biological macromolecules contain both hydrophilic groups (such as OH, NH2 and COOH) and hydrophobic groups (for example hydrocarbons) and the relative amounts of these influence solubility (for further information see Section 3.7 in Catch Up Chemistry).
Interactions with water play an important part in determining the structure of these biological molecules. Generally speaking, hydrophilic groups tend to be exposed on the surface of a molecule or structure from where they are able to interact with water molecules. In contrast, hydrophobic groups tend to orientate themselves towards the inside of the molecule or structure where they interact with each other forming hydrophobic bonds. Interactions between hydrophobic chains of fatty acids allow the formation of cell membranes (see Chapter 4). Other molecules that are associated with membranes, such as proteins, often have hydrophobic regions which are inserted into the membrane to form an anchor.
Water is also very important as a medium of transport and forms the basis of blood. Gases dissolve in water, and this is important in allowing oxygen to be taken to cells and carbon dioxide to be removed.
1.2 Water in the human body
Approximately 60% of the weight of the human body is water – thus a 60 kg person will contain approximately 36 litres of water. Within the body the water is distributed between three main compartments. The bulk of body water (65%) is contained in the cytoplasm of cells and is known as intracellular fluid. Most of the remaining extracellular fluid is divided into the interstitial fluid (25%) which bathes the cells and the plasma (7.5%) which is contained within the blood vessels of the circulatory system. The remaining 2.5% of fluid is known as transcellular fluid and includes, for example, the water in the bladder and the contents of the gastrointestinal tract.
Intracellular fluid is separated from interstitial fluid by the plasma membrane of the cell (see Chapter 6). The ionic composition of these two compartments is dramatically different. The extracellular fluid has a similar composition to seawater and contains approximately 140 mmol Na+ and 110 mmol Cl–. Extracellular fluid also contains significant levels of bicarbonate ions. By contrast, intracellular fluid contains high levels of K+ (approximately 160 mmol compared with 4 mmol in extracellular fluid) and low levels of Na+ (10 mmol). The intracellular negative charge is provided not by Cl– but by proteins, bicarbonate and phosphate ions.
The concentration gradients of Na+ and K+ across cell membranes form the basis of many physiological processes (see Chapters 9 and 22). Ions contained within body fluids are known as electrolytes.
A general rule which applies when considering the ionic balance of any one compartment is that it should contain equivalent positive and negative charges (determined by the relative numbers of cations and anions). Each compartment is said to be electroneutral. This has significance when considering the movement of ions across membranes because, wherever possible, the body strives to ensure that movement of positively charged cations is accompanied by an equivalent negative charge in anions. When this does not happen electrical potentials are generated across membranes and this forms the basis of the function of excitable tissues (see Chapter 16).
The two components of extracellular fluid are separated from each other by the capillary wall. In most capillaries this is freely permeable to the movement of ions and small organic molecules but does not allow the passage of proteins. Thus under normal circumstances interstitial fluid contains no protein whereas both plasma and intracellular fluid are protein rich.
Clinical example: Dehydration
On a hot day a runner may lose up to 2 litres per hour in sweat. For a normal individual a loss of water constituting more than 3% of body weight (about 2 litres) may lead to the early stages of clinical dehydration and cause feelings of light-headedness and disorientation. Further water loss will affect the ability of cells to function and may lead to death due to shock caused by low blood volume. This is why it is particularly important for fun runners to ensure that they take on plenty of water when competing in marathons and other long-distance races.
1.3 Test yourself
The answers are given on p. 175.
Question 1.1
Where in a biological macromolecule would hydrophobic groups generally be found?
Question 1.2
What are the three main compartments in which body water is distributed?
Question 1.3
What is the main cation of: (a) extracellular fluid; (b) intracellular fluid?
Question 1.4
Organic molecules are based around which element?
Question 1.5
Which key component of plasma does not normally pass across the capillary wall?
02
Proteins
Basic concepts:
Proteins are macromolecules assembled as a sequence of amino acids. There are twenty different amino acids, giving rise to a wide range of possible proteins. According to the particular amino acid sequence, proteins will adopt different three-dimensional structures. Proteins are present in all cells and can perform many roles, including as structural elements and as enzymes. It is important to understand how the amino acid sequence of proteins can determine the properties of different proteins, and also how these properties can be altered by external factors such as the binding of another molecule or the addition of a phosphate group.
2.1 Introduction
Proteins are a highly diverse and important group of molecules, central to life. Proteins are biological macromolecules and are polymers of amino acids.
Figure 2.1. General structure of an amino acid
Amino acids contain an amino group and a carboxylic acid group (Fig. 2.1), both attached to an alpha carbon atom. Also attached to the alpha carbon is a side chain, which is different in different amino acids (Fig. 2.2). Side chains have their properties too – some carry a positive or negative charge, some are polar and others are hydrophobic (they prefer not to be in contact with water). The different properties of the side chains are important in determining the structure and function of proteins. There are twenty different amino acids that are found in proteins. Because these can occur in different orders and combinations, this leads to a very large number of possible protein structures.
Figure 2.2. Examples of different kinds of amino acids
Amino acids can exist as different isomers, depending upon the arrangement of the groups attached to the alpha carbon. Isomers are defined as ‘two or more different compounds with the same chemical formula but different structures and characteristics’. The alpha carbon in an amino acid participates in four covalent bonds forming a tetrahedral arrangement, and mirror image forms can exist, called enantiomers. The different enantiomers are described by the letters D and L. All amino acids occurring in proteins are L-isomers.
Figure 2.3. D and L forms of amino acids
Amino acids are joined together by peptide bonds (Fig. 2.4). A peptide bond is formed in a reaction between the carboxylic acid group of one amino acid and the amino group of another. In the process, a molecule of water is lost and so this is called a condensation reaction.
Figure 2.4. Formation of a peptide bond between two amino acids
The amino acids at each end of a protein molecule participate in only one peptide bond, hence they have either a free NH2 group or a free COOH group. The end of the polypeptide chain with a free amino group is called the N-terminus, and the end with the free carboxyl group is called the C-terminus.
2.2 Primary structure
Each protein has its own unique amino acid sequence. The sequence of amino acids in a protein defines its primary structure and this sequence is encoded by the gene for the protein.
Depending on the amino acid sequence, proteins will, under physiological conditions, preferentially adopt a particular folded structure, or conformation (see the sections on secondary and tertiary structure below). The conformation of the protein is maintained by non-covalent interactions involving amino acid side chains. These include ionic bonds between positive and negatively charged amino acid residues, hydrogen bonds, van der Waals forces and hydrophobic interactions (see Catch Up Chemistry for further information on these). Hydrophobic interactions are particularly important as they