Chapter 6: Digestion and Human Health Flashcards
Dehydration Synthesis
A chemical reaction where -OH (hydroxyl) is taken from one subunit, and a hydrogen atom is taken from another subunit so the subunits can bond together.
Hydrolysis
A chemical reaction where water is added to cause a macromolecule to split into two subunits. These subunits receive the -OH and H from the added water.
Carbohydrate
An organic macromolecule that contains carbon, hydrogen, and oxygen in a 1:2:1 ratio.
Ex: monosaccharides, disaccharides, polysaccharides
Lipid
Group of organic macromolecules, including fats, oils, phospholipids, and steroids.
Protein
Organic macromolecule assembled from subunits of amino acids.
Peptide Bond
Bond between the amino group of one amino acid and the carboxyl group of another in a protein.
Nucleic Acid
Macromolecule formed from a long chain of nucleotide subunits. The two types include DNA and RNA.
Vitamin
Organic compound required in trace amounts for normal metabolism.
Mineral
Inorganic compound required in trace amounts for normal metabolism.
Catalyst
A chemical that speeds up a chemical reaction but is not used up in the reaction.
Enzyme
Protein molecule that acts as a catalyst to increase the rate of a reaction.
Digestive System
The system into which food is taken and broken down so that useful substances can be absorbed into and transported by the circulatory system to individual cells.
Mouth
The opening in which food enters the body. Chews and mixes food with saliva and sends it to the esophagus as the bolus.
Amylase
Enzyme in saliva that breaks down starch into simpler sugars.
Esophagus
Direct food (bolus) from the mouth to the stomach.
Peristalsys
Wavelike series of muscular contractions and relaxations. This causes a substance to be moved.
Esophageal Sphincter
A ringlike muscular structure that controls foods entry to the stomach.
Macromolecule
A complex assembly of organic molecules.
The four categories of macromolecules are carbohydrates, lipids, proteins, and nucleic acids.
Stomach
J-shaped sac lying between the esophagus and the small intestine whose muscles ad secretions work to physically and chemically break down food and push it into the small intestine.
Pyloric Sphincter
Controls the exit of the stomach’s contents into the small intestine.
Pepsin
A protein digesting enzyme that is secreted into the stomach. It remains inactive until hydrochloric acid is present.
Small Intestine
Made of the duodenum, jejunum, and ileum. The part of the digestive tract between the stomach and the large intestine. Its main function is to complete the digestion of macromolecules and absorb their subunits.
Segmentation
The process by which some physical digestion occurs in the small intestine. Chyme sloshes back and forth in the small intestines breaking up macromolecules.
Duodenum
First section of the small intestine. Important for chemical digestion of chyme from the stomach.
Villi
Finger-like projections along the ridges of the small intestine; increases surface area to aid in the absorption of nutrients.
Microvilli
Projections that greatly increase the cells surface area. They are found on the villi of the small intestine and on the membranes of certain cells.
Pancreas
Small gland that secretes digestive enzymes into the small intestine, as well as bicarbonate to neutralize hydrochloric acid from the stomach.
Liver
An accessory organ of the digestive system which secretes bile to digest fats.
Gall Bladder
Organ that stores bile produced by the liver.
Carbohydrase
Enzyme that catalyses the hydrolysis of carbohydrates.
Lipase
Enzyme that catalyses the hydrolysis of triglycerides into glycerol and fatty acids.
Protease
Enzyme that hydrolyzes the peptide bonds that link amino acids in proteins and peptides.
Nuclease
Enzyme that hydrolyses the bonds between nucleotides in the nucleic acids.
Gastrin
Stomach hormone that stimulates the secretion of hydrochloric acid and the inactive precursor molecule of pepsin from glands in the stomach.
Secretin, CCK, GIP
Enables fatty meals to stay in the stomach longer than non-fatty meals. Also stimulates the pancreas to release more bicarbonate to neutralize acidic chime.
Ulcer
Slow-healing sore that forms when the thick layer of mucus that protects the lining of the stomach from the acids in digestive juices is eroded.
Inflammatory Bowel Disease
Disease that causes inflammation in the intestines (bowels). Examples are Crohn’s disease and colitis.
Hepatitis
Inflammation of the liver tissue.
Cirrhosis
A disorder of the liver in which scar tissue replaces healthy liver tissue and prevents the liver from functioning properly.
Gallstone
Small, hard mass that forms in the gall bladder when cholesterol precipitates out of the bile and forms crystals that grow in size.
Anorexia Nervosa
Eating disorder characterized by a morbid fear of gaining weight and misconception of body image.
Obesity
Condition in which body mass is 20 percent or more above what is considered to be an ideal body mass for a person’s height.
