Crash Course Metabolism and Nutrition

Preface vi
Acknowledgement viii
Series editor’s acknowledgement ix
Rapid MLA Index x
1 Cellular biology 1
Introduction 1
Eukaryotic organelles 1
The cell membrane 3
The cytoskeleton, cell motility and intracellular
transport 4
Genetics 6
Epigenetics 10
2 Introduction to metabolism 15
Introductory concepts 15
Key molecules in metabolism 23
3 The tricarboxylic acid (TCA) cycle 29
Introduction 29
Key points 29
4 Oxidative phosphorylation 35
Adenosine triphosphate generation 35
Substrate-level phosphorylation 35
Oxidative phosphorylation 36
5 Carbohydrate metabolism 41
Carbohydrates: a definition 41
Carbohydrate digestion 41
Glucose entry into cells 42
Glycolysis 43
The insulin:glucagon ratio influence on glycolysis 47
Aerobic glycolysis versus anaerobic glycolysis 47
Hyperlactataemia 47
Hereditary red cell enzymopathies 47
The pyruvate → acetyl-CoA reaction 48
Regulation of PDH 48
Plasma glucose concentration regulation and
prevention of hypoglycaemia 48
Timescale of glycogenolysis versus gluconeogenesis 48
Gluconeogenesis 48
Gluconeogenic substrates 49
Sequence of gluconeogenesis 49
Key differences between gluconeogenesis and
glycolysis 49
Regulation of gluconeogenesis 50
Glycogen metabolism 50
Glycogen stores 50
Glycogen structure 50
Glycogen synthesis (glycogenesis) 51
Glycogen breakdown (glycogenolysis) 52
Regulation of glycogen metabolism 52
Glycogen storage diseases 54
The pentose phosphate pathway 55
Reactions of the PPP 56
Regulation of the PPP 56
Glucose-6-phosphate dehydrogenase deficiency;
the failure of the PPP 56
Glutathione 57
Fructose metabolism 57
Genetic deficiencies of fructose metabolism 58
Galactose metabolism 58
Sorbitol metabolism 58
Ethanol metabolism 59
Impact of ethanol catabolism 60
6 Glucose homeostasis and diabetes mellitus 63
Hormonal aspects of glucose regulation 63
Metabolic syndrome 67
Diabetes mellitus 69
7 Lipid metabolism and lipid transport 81
Lipids: An introduction 81
Fatty acid biosynthesis 83
Lipid catabolism 88
Cholesterol 93
Lipid transport 94
Exogenous lipids 95
Endogenous lipids 96
Dyslipidaemias 98
Primary dyslipidaemia 98
Familial hypercholesteraemia 99
Secondary dyslipidaemias 99
Clinical management of dyslipidaemias 101
Complications of dyslipidaemia 101
Ketones and ketogenesis 103
8 Energy balance and obesity 107
Body composition 107
Energy balance 108
Appetite regulation: hunger and satiety 109
Clinical aspects of obesity 111
Clinical consequences of obesity 113
Obesity treatment strategies 116
9 Protein metabolism and malnutrition 119
The structure of proteins 119
Essential and non-essential amino acids 122
Amino acid synthesis 122
Biological derivatives of amino acids 127
Nitrogen balance 128
Amino acid catabolism 128
Protein degradation 134
Protein synthesis 134
Dietary protein 138
Parenteral and enteral nutrition 141
Refeeding syndrome 142
10 One-carbon transfer, purines, pyrimidines and haem 145
An overview of one-carbon metabolism 145
Purines and pyrimidines: an overview 146
Purine metabolism 146
Pyrimidines 153
Haem 155
Porphyrias 162
Lead poisoning 164
Clinical Case – Jaundice 165
11 The thyroid gland 167
Introduction 167
Anatomy 167
Histology 168
Thyroid hormones 168
Thyroid homeostasis: the hypothalamic–
pituitary–thyroid axis 170
Secretion and transport of thyroid hormones 170
The function and physiology 171
Disorders of thyroid function 173
Investigations of thyroid function 177
12 Vitamins and their deficiencies 181
Introduction 181
Fat-soluble vitamins 181
Vitamin A (fat soluble) 184
Vitamin D (fat soluble) 185
Vitamin E (fat soluble) 187
Vitamin K (fat soluble) 187
Water-soluble vitamins 189
Thiamine: vitamin B1 (water soluble) 189
Riboflavin: vitamin B2 (water soluble) 190
Niacin: vitamin B3 (water soluble) 191
Pantothenic acid: vitamin B5 (water soluble) 192
Pyridoxine: vitamin B6 (water soluble) 192
Biotin: vitamin B7 (water soluble) 192
Folate: vitamin B9 (water soluble) 193
Cobalamin: vitamin B12 194
Vitamin C (water soluble) 196
13 Minerals and their deficiencies 199
Introduction 199
Sodium, potassium and chloride 199
Calcium 205
Phosphorus 209
Magnesium 209
Iron 210
Zinc 213
Copper 214
Iodine 214
Other trace elements 215
Useful references 217
14 Clinical assessment of metabolism and nutritional disorders 219
Introduction 219
History-taking 219
Common presenting complaints in nutritional
and metabolic disorders 219
Examination 224
Dehydration 232
Relevant investigations 233
Newborn blood spot screening 238
Self-Assessment 241
MLA High-yield association table 243
MLA Single best answer (SBA) questions 245
MLA SBA answers 261
OSCEs and short clinical cases 273
Glossary 311
Index 315