Chapter 26 – Nutrition and Metabolism (Vocabulary Review)

Vocabulary flashcards covering key terms from Chapter 26, Nutrition and Metabolism, including macronutrients, metabolic pathways, hormones, and clinical conditions.

Obesity

Body weight >20 % above recommended norm for age, sex, height; BMI ≥30.

Body Mass Index (BMI)

Weight-to-height ratio (kg/m²) used to classify underweight, normal, overweight, and obesity.

Kilocalorie (kcal)

Amount of heat needed to raise 1 kg of water 1 °C; the ‘calorie’ of dietetics.

Fuel (biological)

Substance primarily oxidized to extract energy for ATP production.

Nutrient

Any ingested chemical used for growth, repair, or maintenance of the body.

Macronutrient

Nutrient required in large amounts: water, carbohydrates, lipids, proteins.

Micronutrient

Nutrient needed in small amounts: vitamins and minerals.

Muscle Glycogen

Storage form of glucose in skeletal muscle; ~325 g in a well-nourished adult.

Liver Glycogen

Glucose storage in the liver; ~90-100 g in adults.

Hypoglycemia

Deficiency of blood glucose causing nervous-system disturbances.

Monosaccharide

Single-sugar unit such as glucose, galactose, or fructose.

Disaccharide

Sugar composed of two monosaccharides; e.g., sucrose, lactose, maltose.

Polysaccharide

Complex carbohydrate of many glucose units; includes starch, glycogen, cellulose.

Glycemic Index (GI)

Measure of a carbohydrate’s effect on blood glucose levels.

Dietary Fiber

All indigestible plant material such as cellulose, pectin, gums, lignins.

Water-Soluble Fiber

Fiber that lowers blood cholesterol and LDL; e.g., pectin in oats and fruits.

Water-Insoluble Fiber

Fiber that adds bulk, softens stool, and speeds transit; e.g., cellulose.

Saturated Fat

Lipid with no double bonds; mainly from animal sources and some tropical oils.

Unsaturated Fat

Lipid with one or more double bonds; found in nuts, seeds, vegetable oils.

Essential Fatty Acid

Fatty acid the body cannot synthesize; must be obtained in the diet.

Cholesterol

Steroid precursor of bile salts, vitamin D, and hormones; component of membranes.

Chylomicron

Largest serum lipoprotein that transports dietary triglycerides from intestine.

Very-Low-Density Lipoprotein (VLDL)

Lipoprotein made by liver to transport triglycerides to tissues.

Low-Density Lipoprotein (LDL)

‘Bad’ cholesterol carrier delivering cholesterol to peripheral tissues.

High-Density Lipoprotein (HDL)

‘Good’ lipoprotein that removes excess cholesterol and returns it to liver.

Amino Acid Pool

Body’s circulating and intracellular free amino acids from diet and protein turnover.

Essential Amino Acid

Amino acid that cannot be made by the body and must be eaten.

Net Protein Utilization

Percentage of amino acids in a protein the body can use (70–90 % animal, 40–70 % plant).

Mineral

Inorganic element required for normal body functions, e.g., Ca²⁺, Fe, P.

Vitamin

Small organic compound needed in trace amounts for metabolism.

Coenzyme

Organic molecule (often vitamin-derived) that assists enzyme function, e.g., NAD⁺, FAD.

NAD⁺ (Nicotinamide Adenine Dinucleotide)

Niacin-derived coenzyme that carries electrons as NADH.

FAD (Flavin Adenine Dinucleotide)

Riboflavin-derived coenzyme that carries electrons as FADH₂.

Glycolysis

Anaerobic pathway splitting glucose into two pyruvate molecules, net 2 ATP.

Pyruvate

Three-carbon product of glycolysis; substrate for fermentation or aerobic respiration.

Anaerobic Fermentation

Reduction of pyruvate to lactate, regenerating NAD⁺ without O₂.

Lactate

Three-carbon acid produced during anaerobic fermentation; can be recycled by liver.

Aerobic Respiration

Oxidation of pyruvate to CO₂ and H₂O in presence of O₂, producing most ATP.

Acetyl-CoA

Two-carbon acetyl group bound to coenzyme A; entry molecule for citric acid cycle.

Citric Acid Cycle

Series of matrix reactions oxidizing acetyl-CoA, generating NADH, FADH₂, ATP.

Electron Transport Chain

Series of membrane proteins that pass electrons and pump protons to make ATP.

Chemiosmotic Mechanism

ATP synthesis driven by H⁺ gradient flowing through ATP synthase.

Glycogenesis

Formation of glycogen from glucose; stimulated by insulin.

Glycogenolysis

Breakdown of glycogen to glucose; stimulated by glucagon and epinephrine.

Gluconeogenesis

Synthesis of glucose from non-carbohydrate precursors like amino acids or glycerol.

Lipogenesis

Conversion of acetyl-CoA or sugars into triglycerides for storage.

Lipolysis

Hydrolysis of triglycerides into glycerol and free fatty acids for fuel.

Beta Oxidation

Catabolic process removing two-carbon units from fatty acids to form acetyl-CoA.

Ketone Body

Acetoacetic acid, β-hydroxybutyric acid, or acetone produced in liver during fat metabolism.

Ketosis

Elevated blood ketone levels from rapid fat oxidation.

Ketoacidosis

Dangerous drop in blood pH due to excessive ketone bodies.

Deamination

Removal of an amino group (-NH₂) from an amino acid.

Transamination

Transfer of an amino group from one molecule to another.

Urea Cycle

Hepatic pathway converting toxic ammonia to urea for excretion.

Absorptive (Fed) State

Metabolic period during and shortly after eating when nutrients are abundant.

Postabsorptive (Fasting) State

Metabolic period between meals relying on stored fuels.

Insulin

Pancreatic β-cell hormone promoting glucose uptake, glycogenesis, and lipogenesis.

Glucagon

Pancreatic α-cell hormone stimulating glycogenolysis, gluconeogenesis, and lipolysis.

Growth Hormone

Anterior pituitary hormone that raises blood glucose and promotes protein synthesis.

Cortisol

Adrenal glucocorticoid that stimulates gluconeogenesis and protein catabolism under stress.

Sympathoadrenal System

Combined sympathetic nerves and adrenal medulla releasing epinephrine/norepinephrine.

Cachexia

Extreme wasting from chronic disease due to anorexia and altered metabolism.

Hepatitis

Inflammation of the liver, commonly viral (types A, B, C, etc.).

Cirrhosis

Irreversible scarring of liver tissue, often from chronic alcohol abuse.

Ascites

Accumulation of serous fluid in the peritoneal cavity, often due to liver failure.

Metabolic Water

Water produced internally by cellular respiration.

Empty Calories

Energy-rich foods (e.g., alcohol, sugar) with little nutritional value.

Essential Mineral

Mineral the body cannot synthesize, required in diet (e.g., Ca²⁺, Fe, Mg²⁺).

Hypervitaminosis

Toxicity from excessive intake of fat-soluble vitamins (e.g., vitamin A).

Night Blindness

Vision disorder caused by vitamin A deficiency.

Beta Oxidation Yield

Energy obtained from fatty acid oxidation; 16-carbon fatty acid yields ~129 ATP.

Net ATP from Glucose

Complete aerobic oxidation of one glucose produces ~32 ATP.

GTP (Guanosine Triphosphate)

High-energy nucleotide formed in citric acid cycle that quickly converts to ATP.

Proton Pump

Electron-transport protein complex that translocates H⁺ across the mitochondrial membrane.

ATP Synthase

Mitochondrial enzyme channel that couples H⁺ flow to ATP production.

Adiposity Signal

Hormonal cue (e.g., insulin, leptin) informing the brain about body fat stores.

Ketogenesis

Formation of ketone bodies from excess acetyl-CoA in the liver.

Electrolyte

Mineral salt that dissociates in water and conducts electricity, vital for nerve/muscle function.