Macromolecules, Nutrition, and the Human Digestive System

Comprehensive vocabulary flashcards covering macromolecules, enzymatic reactions, feeding mechanisms, stages of digestion, human digestive anatomy, and gastrointestinal disorders.

Macromolecules

Large, complex organic molecules that act as nutrients, providing energy and the raw materials needed to build and repair body tissues.

Carbohydrates

Organic molecules containing carbon, hydrogen, and oxygen whose primary functions are providing short-term energy and energy storage.

Lipids

Water-insoluble macromolecules typically made of a glycerol backbone and fatty acids that provide long-term energy storage and contain approximately 2.25 times more energy per gram than carbohydrates.

Proteins

Macromolecules made of amino acids linked by peptide bonds that function to build and repair tissues and form enzymes and antibodies.

Nucleic Acids

Macromolecules made of nucleotide subunits (DNA and RNA) that provide the chemical code responsible for the characteristics and functioning of living organisms.

Metabolism

The sum of all the chemical reactions that occur within an organism.

Essential Nutrients

Nutrients that the body cannot synthesize on its own and must obtain from food.

Monosaccharide

A carbohydrate consisting of a single sugar unit, such as glucose or fructose.

Disaccharide

A carbohydrate composed of two sugar units joined together, such as sucrose, maltose, or lactose.

Polysaccharide

A complex carbohydrate composed of many joined sugar units, such as starch, cellulose, or glycogen.

Triglyceride

A lipid composed of 1 glycerol backbone attached to 3 fatty acids that functions in long-term energy storage, insulation, and organ protection.

Saturated Fatty Acid

A fatty acid having a straight carbon chain with no carbon-carbon double bonds.

Unsaturated Fatty Acid

A fatty acid possessing one or more carbon-carbon double bonds, which can introduce bends in the chain.

Peptide Bond

The chemical bond that links amino acids together to form polypeptide chains.

Polypeptides

Long chains of amino acids joined together by peptide bonds that fold into specific shapes to form functional proteins.

Hydrolysis

A chemical reaction that breaks larger molecules and chemical bonds apart by adding water, which is essential during digestion.

Dehydration Synthesis

A chemical reaction that joins smaller molecules and forms chemical bonds by removing a water molecule.

Enzymes

Protein biological catalysts produced by ribosomes that accelerate chemical reactions without being consumed in the process.

Active Site

The specific region of an enzyme where the substrate binds to undergo a chemical reaction.

Carbohydrases

The group of digestive enzymes responsible for breaking down polysaccharides and carbohydrates.

Proteases

The group of digestive enzymes responsible for breaking down polypeptides and proteins.

Lipases

The group of digestive enzymes responsible for breaking down fats and lipids.

Nucleases

The group of digestive enzymes responsible for breaking down nucleic acids.

Amylase

A carbohydrate-digesting enzyme found in saliva that breaks down starch into simpler sugars in the mouth.

Pepsin

A protein-digesting enzyme in the stomach that is secreted in an inactive form and activated by hydrochloric acid.

Vitamins

Organic substances required in small quantities that help regulate body processes and facilitate chemical reactions.

Minerals

Inorganic substances required by the body for normal cellular and physiological functions, such as calcium, iron, and sodium.

Filter Feeding

A feeding mechanism where animals, such as baleen whales and clams, use specialized structures to strain small food particles from water.

Fluid Feeding

A feeding mechanism where organisms, such as mosquitoes and hummingbirds, ingest nutrient-rich liquids from plants or animals.

Substrate Feeding

A feeding mechanism where animals, such as caterpillars and maggots, live directly on or within their food source and eat their way through it.

Bulk Feeding

A feeding mechanism where organisms, such as humans and lions, consume large pieces of food using structures like teeth or jaws.

Alimentary Canal

A continuous digestive tract running from the mouth to the anus through which food passes and undergoes sequential processing.

Bolus

A soft mass of chewed and lubricated food gathered by the tongue before swallowing.

Epiglottis

A anatomical flap structure that covers the entrance to the trachea (windpipe) during swallowing to prevent food from entering.

Peristalsis

Coordinated waves of muscular contractions behind food and relaxations ahead of food that propel contents through the digestive tract.

Esophageal Sphincter

A muscular valve regulating entry into the stomach that remains closed to prevent acidic stomach contents from entering the esophagus.

Chyme

The thick, acidic liquid produced in the stomach when partially digested food mixes thoroughly with gastric juice.

Pyloric Sphincter

A muscular valve that controls the regulated passage of chyme from the stomach into the duodenum of the small intestine.

Duodenum

The first section of the small intestine, which receives chyme along with digestive secretions from the pancreas and gallbladder.

Jejunum

The second region of the small intestine containing numerous folds, responsible for continuing digestion and absorbing carbohydrate and protein nutrients.

Ileum

The final region of the small intestine that absorbs remaining nutrients and transfers undigested waste into the large intestine.

Bile

A digestive fluid produced by the liver and stored in the gallbladder that physically breaks large fat droplets into smaller droplets.

Bicarbonate

A basic substance secreted by the pancreas into the duodenum to neutralize acidic gastric chyme and raise pH.

Villi

Finger-like projections lining the inner surface of the small intestine that significantly increase surface area for nutrient absorption.

Microvilli

Microscopic projections covering the epithelial cells of villi that further increase surface area for absorption.

Lacteal

A small lymphatic vessel situated inside each villus that absorbs the products of lipid digestion.

GERD (Acid Reflux)

A disorder where stomach acid moves backward into the esophagus, producing mucosal irritation and heartburn.

Peptic Ulcers

Sores that develop along the lining of the stomach or upper small intestine.

Celiac Disease

An autoimmune disorder in which gluten consumption causes immune-mediated damage to the lining and villi of the small intestine.

Crohn's Disease

An inflammatory bowel disease that can cause chronic inflammation across different parts of the digestive tract.

Ulcerative Colitis

An inflammatory bowel disease characterized by inflammation confined to the colon and rectum.