Chapter 18 – Nutrition & Metabolism Vocabulary

A comprehensive set of vocabulary flashcards covering key terms, molecules, hormones, vitamins, minerals, and disorders discussed in the Chapter 18 lecture on nutrition and metabolism.

Nutrient

A chemical from the environment that an organism needs for survival, energy, and building cellular components.

Macronutrient

A nutrient required in large amounts (carbohydrates, lipids, proteins).

Micronutrient

A nutrient needed in small amounts (vitamins and minerals).

Essential nutrient

A nutrient the body cannot synthesize—or cannot make in sufficient quantity—and must obtain from the diet.

Carbohydrate

An organic compound (sugars, starches) whose chemical-bond energy powers cellular processes.

Polysaccharide

A complex carbohydrate composed of many sugar units; examples include plant starch and animal glycogen.

Glycogen

Animal storage form of glucose; abundant in liver and muscle.

Disaccharide

A double sugar such as sucrose or lactose.

Monosaccharide

A single-sugar molecule (glucose, fructose, galactose).

Cellulose

Indigestible plant fiber that provides bulk (roughage) in the diet.

Glycogenesis

The conversion of excess glucose into glycogen for storage.

Lipogenesis

The conversion of excess glucose into fat for storage in adipose tissue.

Triglyceride

The most common dietary lipid; a fat molecule consisting of glycerol plus three fatty acids.

Saturated fat

A fat whose fatty acids contain no double bonds; mostly from animal sources and linked to cardiovascular risk.

Unsaturated fat

A fat with one or more double bonds in its fatty acids; mainly from plant oils and considered healthier.

Monounsaturated fat

An unsaturated fat containing one double bond; regarded as the healthiest type of dietary fat.

Cholesterol

A sterol found in animal foods and synthesized by the liver; precursor of bile salts and steroid hormones.

Phospholipid

A lipid containing a phosphate group; major structural component of cell membranes.

Essential fatty acid

A fatty acid the liver cannot make (e.g., linoleic acid) and must be supplied by food.

Lipoprotein

A lipid–protein complex that transports lipids in blood; classified by density.

VLDL

Very-low-density lipoprotein rich in triglycerides.

LDL

Low-density lipoprotein carrying high cholesterol; "bad" cholesterol.

HDL

High-density lipoprotein rich in protein; "good" cholesterol that helps remove excess cholesterol.

Protein

A macromolecule of amino-acid chains serving structural, enzymatic, hormonal, antibody, and energy roles.

Essential amino acid

One of eight (adult) amino acids the body cannot synthesize and must obtain from diet.

Complete protein

A food protein containing adequate amounts of all essential amino acids (e.g., meat, eggs, milk).

Nitrogen balance

State in which nitrogen intake equals nitrogen excretion; indicates protein equilibrium.

Positive nitrogen balance

Condition (e.g., growth, pregnancy) where intake exceeds loss and new tissue forms.

Negative nitrogen balance

Condition (e.g., starvation) where excretion exceeds intake, leading to tissue breakdown.

Basal Metabolic Rate (BMR)

Energy expenditure of the body at rest, post-absorptive state, comfortable temperature.

Energy balance

Equilibrium in which caloric intake equals caloric output; weight remains constant.

Body Mass Index (BMI)

Weight-for-height index used to classify underweight, normal, overweight, and obesity.

Appetite

The drive to seek food, regulated by hormones and neurotransmitters.

Insulin

Pancreatic hormone that promotes glucose uptake and fat storage after eating; can suppress appetite.

Leptin

Adipocyte hormone that suppresses appetite and increases metabolic rate by inhibiting neuropeptide Y.

Ghrelin

Stomach hormone that stimulates appetite via neuropeptide Y release.

Neuropeptide Y

Hypothalamic neurotransmitter that powerfully enhances appetite.

Vitamin

An organic compound required in small amounts for normal metabolism and not produced in adequate quantity by the body.

Fat-soluble vitamins

Vitamins A, D, E, and K that dissolve in fats and can be stored in body tissues.

Water-soluble vitamins

B-complex vitamins and vitamin C; not stored extensively and easily lost in cooking water.

Vitamin A

Fat-soluble antioxidant needed for vision pigments, epithelial maintenance, bone and tooth growth.

Vitamin D

Fat-soluble steroid that promotes calcium and phosphorus absorption and bone mineralization.

Vitamin E

Fat-soluble antioxidant that protects cell membranes and prevents oxidation of vitamin A and PUFAs.

Vitamin K

Fat-soluble vitamin necessary for hepatic synthesis of prothrombin and normal blood clotting.

Thiamine (B1)

Water-soluble vitamin part of a coenzyme in carbohydrate oxidation; deficiency causes beriberi.

Riboflavin (B2)

Water-soluble vitamin component of FAD coenzymes in cellular energy metabolism.

Niacin (B3)

Water-soluble vitamin forming NAD/NADP coenzymes; deficiency leads to pellagra.

Pantothenic acid (B5)

Vitamin forming part of coenzyme A for carbohydrate and fat oxidation.

Vitamin B6

Group of compounds acting as coenzymes in amino-acid metabolism and hemoglobin synthesis.

Biotin (B7)

Coenzyme for amino-acid and fatty-acid metabolism and nucleic-acid synthesis.

Folic acid (B9)

Coenzyme for DNA synthesis and red-blood-cell production; deficiency causes megaloblastic anemia.

Vitamin B12

Cobalt-containing vitamin needed for nucleic-acid synthesis and myelin maintenance; intrinsic factor required for absorption.

Vitamin C

Ascorbic acid; required for collagen formation, iron absorption, and immune function; deficiency causes scurvy.

Mineral

Inorganic element essential in metabolism, structural components, and physiological processes.

Major mineral

Mineral needed in amounts ≥0.05% body weight (e.g., calcium, phosphorus, sodium).

Trace element

Essential mineral required in minute quantities (<0.005% body weight) such as iron, iodine, zinc.

Calcium

Major mineral for bone/teeth structure, neurotransmitter release, muscle contraction, blood clotting.

Phosphorus

Major mineral in bones, nucleic acids, ATP, and cell membranes.

Potassium

Major intracellular cation vital for nerve impulse conduction and acid-base balance.

Sodium

Extracellular cation important for osmotic pressure, nerve impulses, and water balance.

Chloride

Extracellular anion forming hydrochloric acid and aiding carbon-dioxide transport.

Magnesium

Cofactor for ATP-producing reactions; abundant in bone.

Iron

Trace element forming hemoglobin and certain enzymes; deficiency leads to anemia.

Iodine

Trace element essential for thyroid hormone synthesis.

Zinc

Trace element needed for enzyme activity, wound healing, and immune function.

Malnutrition

Poor nutrition resulting from either deficiency or excess of nutrients.

Marasmus

Severe malnutrition from total calorie and protein deficiency.

Kwashiorkor

Protein-deficiency malnutrition characterized by edema and enlarged abdomen.