unit 2: nutrition and digestion, basic chemistry, organic compounds, enzyme function
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123 terms
Terms | Definitions |
|---|---|
 Mouth | takes in food and mechanically and chemically breaks down matter |
| gallbladder | stores bile until it is needed in the small intestine |
| pharynx | makes sure food goes down digestive tract and air into the esophagus |
| trachea | conveys air to and from the lungs |
| epiglottis | is depressed while swallowing to cover the entrance to the windpipe |
| small intestine | runs between the stomach and the large intestine; nutrients are absobed into the blood here and chemical breakdown occurs |
| stomach | links the esophagus to the small intestine; chemical breakdown occurs here |
| large intestine (colon) | absorbs water and vitamin k from the alimentary canal |
| pancreas | secretes digestive enzymes and does a lot of other stuff |
| appendix | not important; contains a mass of white blood cells that helps with immunity |
| liver | processes the products of digestion into substances useful to the body, neutralizes harmful substances in the blood, secretes bile for digestion of fats, synthesizes plasma proteins, stores things. |
| rectum | where feces are stored until they can be eliminated |
| anus | where solid waste matter leaves the body |
| element | any substance that cannot be broken down to any other substance |
| compound | a combination of two or more elements |
| atom | the smallest unit of matter that retains the properties of an element |
| proton | A subatomic particle with a single positive electrical charge, found in the nucleus of an atom |
| neutron | An electrically neutral particle (a particle having no electrical charge), found in the nucleus of an atom |
| electron | A subatomic particle with a single negative charge; one or more electrons move around the nucleus of an atom |
| nucleus (of an atom) | An atom's central core, containing protons and neutrons |
| atomic number | The number of protons in the nucleus of an atom, unique for each element and designated by a subscript to the left of the elemental symbol |
| mass number | The sum of the number of protons and neutrons in an atom's nucleus |
| isotope | One of several atomic forms of an element, each containing a different number of neutrons and thus differing in atomic mass |
| radioactive isotope | An isotope that is unstable; the nucleus decays spontaneously, giving off detectable particles and energy |
| electron shell | An energy level representing the distance of an electron from the nucleus of an atom |
| electronegativity | The attraction of an atom for the electrons of a covalent bond |
| chemical bond | An attraction between two atoms resulting from a sharing of outer-shell electrons or the presence of opposite charges on the atoms; the bonded atoms gain complete outer electron shells |
| ionic bond | A chemical bond resulting from the attraction between oppositely charged ions |
| ion | An atom that has gained or lost electrons, thus acquiring a charge |
| salt | Compounds resulting from the formation of ionic bonds, also called an ionic compound |
| covalent bond | A type of strong chemical bond in which two atoms share one pair of valence electrons |
| polar molecule | A molecule (such as water) with opposite charges on opposite sides |
| hydrophilic | likes water |
| hydrophobic | not liking water |
| hydrogen bond | A type of weak chemical bond formed when the slightly positive hydrogen atom of a polar covalent bond in one molecule is attracted to the slightly negative atom of a polar covalent bond in another molecule |
| nonpolar molecule | Molecule which has no separation of charge, so no positive or negative poles are formed |
| cohesion | The binding together of like molecules, often by hydrogen bonds |
| adhesion | The attraction between different kinds of molecules |
| surface tension | A measure of how difficult it is to stretch or break the surface of a liquid |
| evaporative cooling | sweat on our skin evaporates with the wind causing cooling |
| heat | The total amount of kinetic energy due to molecular motion in a body of matter |
| temperature | A measure of the intensity of heat in degrees, reflecting the average kinetic energy of the molecules |
| density | the degree of compactness of a substance |
| solute | A substance that is dissolved in a solution |
| solvent | The dissolving agent of a solution |
| solution | A homogeneous, liquid mixture of two or more substances |
| acid | A substance that increases the hydrogen ion concentration of a solution |
| base | A substance that reduces the hydrogen ion concentration of a solution |
| buffer | A substance that consists of acid and base forms in a solution and that minimizes changes in pH when extraneous acids or bases are added to the solution |
| pH scale | A measure of hydrogen ion concentration equal to -log [H+] and ranging in value from 0 to 14 |
| chemical reaction | A process leading to chemical changes in matter; involves the making and/or breaking of chemical bonds |
| reactant | A starting material in a chemical reaction |
| product | An ending material in a chemical reaction |
| organic compound | A chemical compound containing the element carbon and usually synthesized by cells |
| hydrocarbon | An organic molecule consisting only of carbon and hydrogen |
| isomer | One of several organic compounds with the same molecular formula but different structures and therefore different properties |
| functional group | A specific configuration of atoms commonly attached to the carbon skeletons of organic molecules and usually involved in chemical reactions |
| hydroxyl | A functional group consisting of a hydrogen atom joined to an oxygen atom by a polar covalent bond. Molecules possessing this group are soluble in water and are called alcohols |
| carbonyl | A functional group present in aldehydes and ketones and consisting of a carbon atom double-bonded to an oxygen atom |
| carboxyl | A functional group present in organic acids and consisting of a single carbon atom double-bonded to an oxygen atom and also bonded to a hydroxyl group |
| amino | A functional group that consists of a nitrogen atom bonded to two hydrogen atoms; can act as a base in solution, accepting a hydrogen ion and acquiring a charge of +1 |
| macromolecule | A giant molecule formed by the joining of smaller molecules, usually by a condensation reaction |
| polymer | A long molecule consisting of many similar or identical monomers linked together |
| monomer | The subunit that serves as the building block of a polymer |
| dehydration synthesis | A chemical process in which a polymer forms as monomers are linked by the removal of water molecules. One molecule of water is removed for each pair of monomers linked |
| hydrolysis | A chemical process that lyses, or splits, molecules by the addition of water; an essential process in digestion |
| carbohydrate | A sugar or one of its dimers or polymers |
| monosaccharide | The simplest carbohydrate, active alone or serving as a monomer for disaccharides and polysaccharides |
| disaccharide | A double sugar, consisting of two monosaccharides joined by dehydration synthesis |
| polysaccharide | A polymer of up to over a thousand monosaccharides, formed by dehydration reactions |
| starch | A storage polysaccharide in plants consisting entirely of glucose |
| glycogen | An extensively branched glucose storage polysaccharide found in the liver and muscle of animals; the animal equivalent of starch |
| cellulose | A structural polysaccharide of cell walls, consisting of glucose monomers joined by b-1, 4-glycosidic linkages |
| lipid | One of a family of compounds, including fats, phospholipids, and steroids, that are insoluble in water |
| fat | A biological compound consisting of three fatty acids linked to one glycerol molecule |
| triglyceride | A fat, which consists of a molecule of glycerol linked to three fatty acids |
| unsaturated | Pertaining to fats and fatty acids whose hydrocarbon chains lack the maximum number of hydrogen atoms and therefore have one or more double covalent bonds |
| saturated | Pertaining to fats and fatty acids whose hydrocarbon chains contain the maximum number of hydrogens and therefore have no double covalent bonds |
| phospholipid | A molecule that is a constituent of the inner bilayer of biological membranes, having a polar, hydrophilic head and a nonpolar, hydrophobic tail |
| wax | A lipid that consists of one fatty acid linked to an alcohol |
| steroid | A type of lipid characterized by a carbon skeleton consisting of four rings with various functional groups attached |
| protein | A three-dimensional biological polymer constructed from a set of 20 different monomers called amino acids |
| enzyme | A protein serving as a catalyst, a chemical agent that changes the rate of a reaction without being consumed by the reaction |
| amino acid | An organic molecule possessing both carboxyl and amino groups |
| peptide bond | The covalent bond between two amino acid units, formed by a dehydration reaction |
| polypeptide | A polymer (chain) of many amino acids linked together by peptide bonds |
| denaturation | For proteins, a process in which a protein unravels and loses its native conformation, thereby becoming biologically inactive |
| primary structure | The level of protein structure referring to the specific sequence of amino acids |
| secondary structure | The localized, repetitive coiling or folding of the polypeptide backbone of a protein due to hydrogen bond formation between peptide linkages |
| alpha helix | A spiral shape constituting one form of the secondary structure of proteins, arising from a specific hydrogen-bonding structure |
| pleated sheet | One form of the secondary structure of proteins in which the polypeptide chain folds back and forth, or where two regions of the chain lie parallel to each other and are held together by hydrogen bonds |
| tertiary structure | Irregular contortions of a protein molecule due to interactions of side chains involved in hydrophobic interactions, ionic bonds, hydrogen bonds, and disulfide bridges |
| quaternary structure | The particular shape of a complex, aggregate protein, defined by the characteristic three-dimensional arrangement of its constituent subunits, each a polypeptide |
| nucleic acid | A polymer consisting of many nucleotide monomers; serves as a blueprint for proteins and, through the actions of proteins, for all cellular activity |
| DNA | A double-stranded, helical nucleic acid molecule capable of replicating and determining the inherited structure of a cell's proteins |
| nucleotide | The building block of a nucleic acid, consisting of a five-carbon sugar covalently bonded to a nitrogenous base and a phosphate group |
| double helix | The form of native DNA, referring to its two adjacent polynucleotide strands wound into a spiral shape |
| kinetic energy | The energy of motion, which is directly related to the speed of that motion |
| heat | The total amount of kinetic energy due to molecular motion in a body of matter |
| potential energy | The energy stored by matter as a result of its location or spatial arrangement |
| chemical energy | Energy stored in the chemical bonds of molecules; a form of potential energy |
| endergonic | A nonspontaneous chemical reaction in which free energy is absorbed from the surroundings |
| exergonic | A spontaneous chemical reaction in which there is a net release of free energy |
| energy of activation | The amount of energy that reactants must absorb before a chemical reaction will start |
| enzyme | A protein serving as a catalyst, a chemical agent that changes the rate of a reaction without being consumed by the reaction |
| substrate | The reactant on which an enzyme works |
| active site | The specific portion of an enzyme that attaches to the substrate by means of weak chemical bonds |
| inhibitor | A substance that reduces the activity of an enzyme by entering the active site in place of the substrate whose structure it mimics |
| omnivore | eats meat and plants |
| herbivore | eats only plants |
| carnivore | eats only meat |
| ingestion | A heterotrophic mode of nutrition in which other organisms or detritus are eaten whole or in pieces |
| digestion | The process of breaking down food into molecules small enough for the body to absorb |
| absorption | The uptake of small nutrient molecules by an organism's own body; the third main stage of food processing, following digestion |
| elimination | The passing of undigested material out of the digestive compartment |
| peristalsis | Rhythmic waves of contraction of smooth muscle that push food along the digestive tract |
| pyloric sphincter | In the vertebrate digestive tract, a muscular ring that regulates the passage of food out of the stomach and into the small intestine |
| villi | A fingerlike projection of the inner surface of the small intestin |
| microvilli | One of many fine, fingerlike projections of the epithelial cells in the lumen of the small intestine that increase its surface area |
| kilocalorie | A thousand calories; the amount of heat energy required to raise the temperature of 1 kg of water by 1°C |
| BMR | The minimal number of kilocalories a resting animal requires to fuel itself for a given time |
| vitamin | An organic molecule required in the diet in very small amounts |
| mineral | In nutrition, a chemical element other than hydrogen, oxygen, or nitrogen that an organism requires for proper body functioning |
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