Glossary for Applications in Biology/Chemistry


abnormal - deviating from the normal or average; markedly irregular

absolute zero - lowest temperature theoretically possible (-273.15oC or 0oK)

absorb - to cause to be taken up by a substance, such as a leaf absorbing oxygen into its tissues

absorption - the process by which a substance takes up materials or energy

acetylene - a hydrocarbon gas (C2H2) used as a fuel

acid-base balance - normal balance between acid and base production and excretion in the body

acid-base neutralization - said of a chemical reaction in which the amounts of acid and base react to form water (and salt) and leave no excess of hydronium (H3O+) or hydroxide (OH-) ions. the resulting solution has a pH of 7.

acidic - the quality of water solutions that contain a high concentration of hydrogen ions (hydrogen atoms with a positive charge). Acidic solutions have a pH less than 7.

acidic solutions - a solution containing an excess of hydrogen ions (H+) making the solution acidic; a pH lower than 7

acid rain - rainwater with a high acid content (pH<5.6) that results from the reaction of water in the air with oxides of nitrogen and sulfur. A major source of these oxides is burning fossil fuels.

Acquired Immune Deficiency Syndrome (AIDS) - a viral infection transmitted through contact with blood or semen that destroys the function of the human immune system

activated carbon - a highly adsorbent form of carbon used to remove contaminants from fluids

activated charcoal - a highly absorbent form of carbon used to remove contaminants from fluids

active solar - the use of sunlight to produce heat by exposing solar collectors to the sun

active transport - movement of molecules through a transport molecule in a cell membrane

acute - a sharp and severe illness, occurring and disappearing rapidly

addiction - a dependence on drugs. Addiction is often referred to as a disease because it damages the body and the mind

adenine - one of the nitrogenous bases in DNA and RNA

adolescents - teenagers; young people between puberty and maturity

adrenal glands - the glands that release the hormones adrenaline and cortisol

adrenaline - one of the hormones responsible for the physiological changes associated with fear, such as increased breathing, higher metabolic rate, and increased sweating. It is secreted by the adrenal glands

adsorb - to cause to adhere to the surface of a substance, such as a substance that adsorbs molecules on its surface

adsorption - process by which one substance is attracted to and held on the surface of another substance.

adsorption capacity - the maximum amount of a matter that can be attracted to and held on the surface of a given amount of a substance

aerobes - organisms that use oxygen in respiration

aerobic - any biological process that occurs in the presence of oxygen

aesthetics - a pleasing appearance or effect

agrochemicals - commercial chemicals used in agriculture, such as livestock hormones, fertilizers, herbicides, and pesticides

AIDS (Aquired Immune Deficiency Syndrome)- a disease caused by a virus that attacks white blood cells and destroys the body's immune system

airborne - in the air

albinism - lacking normal pigmentation in skin, hair, and eyes, causing skin and hair to be completely white and eyes to be pink

alimentary canal - the food tube; that portion of the digestive tract through which food passes

alkaline - the quality of water solutions that contain a high concentration of hydroxide ions (molecules of hydrogen and oxygen with a negative charge). Alkaline (basic) solutions have a pH greater than 7.

alkalosis - abnormally high pH of body fluids

allergy - abnormally strong reaction of the body's immune system to a foreign substance

alveoli - tiny air sacs within the lungs across which gases are exchanged

Alzheimer's disease - a type of senility that can strike people from their early 40s to their 80s. It develops gradually and usually affects short-term memory first. Both the cause and the cure are unknown. The disease is usually fatal after 5 to 15 years

amino acids - essential nutrients used by living cells to synthesize proteins; the building blocks of protein. These acids link together in various combinations to form chains

ammonia - basic (alkaline) compound of nitrogen and hydrogen (NH3) with a pungent odor

amniocentesis - a method for detecting genetic diseases in unborn babies. A needle is inserted through the mother's abdomen to remove fluid from the sac surrounding the fetus in the mother's womb; the fluid and the cells in the fluid can be examined to see if the baby will have a genetic disorder.

amnion - one of four embryonic membranes of vertebrate embryos; protects the embryo in a watery fluid

amniotic fluid - fluid that fills the amnion and cushions and protects the embryo

amphetamine - a type of stimulant, also known as methamphetamine. In pill form, it's called "crank" or "speed"; it can also be found as a powder to be snorted or injected. "Ice" is a crystallized, purified form of amphetamine that can be smoked like crack.

amylase - enzymes secreted by the salivary glands or pancreas that digest starch (amylose)

amyl nitrate - a type of inhalant, originally used to treat heart pain and asthma. Also known as "poppers" or "snappers," amyl nitrate is a clear, yellowish liquid coming in cloth-covered bulbs. When the bulbs are crushed, users breathe the vapors

anabolic steroids - synthetic copies of the male hormone testosterone. By causing the body to retain water, the encourage growth of muscle tissue; therefore, some athletes believe they increase athletic performance. On the other hand, anabolic steroids can stunt overall growth, damage internal organs, impede sexual functions, and cause hallucinations. Females may develop male physical characteristics

anaerobes - organisms that cannot grow in the presence of oxygen

anaerobic - without oxygen

anemia - a condition in which the blood is deficient in red blood cells, in hemoglobin, or in total volume

anesthetic - medication that relieves pain

aneurysm - a weakening in a blood vessel that causes it to bulge and possibly to burst

angiogram - a test on the blood flow to the heart. After dye is injected into a large artery, an X ray records the dye as it travels through the blood vessels into the heart; any blockages show up on the X ray

anion - any atom or group of atoms with a negative charge

anorexia nervosa - a disorder that is characterized by a fear of weight gain leading to faulty eating patterns, malnutrition, and usually excessive weight loss

anthropometry - evaluation of an individual's health and nutritional status through body measurements. In animals body measurement is used to estimate their weight

antibiotic - any substance that prevents the growth of or destroys microorganisms, that is used to treat disease in humans and other animals

antibody - a substance produced by the body that recognizes and binds to substances

anticodon - sequence of three bases in transfer RNA (tRNA) that fits a matching codon of messenger RNA (mRNA)

antigen - a molecule foreign to the body

antiseptic - a substance that prevents the growth of microorganisms that cause infection (used on living tissue)

aqua culture - the raising of aquatic species for commercial purposes; fish and seafood

aquatic - organisms whose normal habitat is water; growing or living in water

aquifer - underground rock formation that contains water

arc welding - the fusing of metals by the heat produced when a luminous discharge of electric current crosses a gap between two electrodes

aroma - a distinctive, pleasant, or savory smell

arrhythmias - changes or irregularities in the rhythm or force of a person's heartbeat

arteries - blood vessels which carry nutrients away from the heart to the body tissues

arterioles - smaller extensions of the artieries

arthritis - an autoimmune disease causing inflammation or swelling of the joints

artificial insemination - introduction of semen into the uterus or oviduct by other than natural means

artificial selection - procedure in which humans choose organisms to breed that have desirable characteristics

asexual - reproduction in which a single parent produces offspring by fragmentation, fission, or mitotic cell division

ash - solids, including minerals, that remain after a substance is burned

asphyxiate - to deprive of oxygen

atherosclerosis - the buildup of plaque in blood vessels. This buildup narrows and stiffens the blood vessels, thereby impeding the blood flow in the vessels

atmosphere - a mixture of gases surrounding the Earth, primarily composed of nitrogen and oxygen

atom - the smallest form of an element that has all the properties of that element

atomic mass - the mass of one atom of a given element; the total number of protons and neutrons which an atom possesses

atomic number - number of protons in the nucleus of an atom (equal to the number of electrons in a neutral atom)

ATP - the primary energy-storage molecules found in cells

autoimmune - referring to diseases, such as diabetes, arthritis, and multiple sclerosis, which occur when the body's immune system attacks the body itself

automatic acidity test - a test done to determine the freshness of raw milk at a dairy

average - sum of a set of values divided by the total number of values

bacteria - single-celled organisms that have no membrane around the DNA of their cells (no nucleus)

bactericidal - an agent that will kill bacteria

balanced diet - diet adequate in energy-providing substances (carbohydrates and fats), tissue-building compounds (proteins), inorganic chemicals (water and mineral salts), and agents that regulate metabolic processes (vitamins)

barbiturate - a type of depressant, available legally through a physician or illegally on the street. In pill form, they are also called "downers," "barbs," and "reds."

basal body temperature (BBT) method - birth-control method in which a woman charts her temperature at the same time each morning to determine when she is ovulating

basal metabolic rate (BMR) - minimum amount of energy (calories) needed by the body at rest, in an awake state, in comfortable environmental conditions, and while fasting

bases - substances that, when mixed with water, from hydroxide ions

basic - alkaline; having a pH greater than 7

Basic-Four-Food-Group - a system of classifying foods according to the proportion of nutrients in them. They are meat, cereal, fruit and vegetable, and milk and dairy products.

basic solutions - a solution containing an excess of hydroxide ions (OH-) making the solution basic; alkaline; having a pH greater than 7

bedrock - layer of earth below topsoil and subsoil, usually solid rock

benign - a tumor that does not threaten surrounding tissue

beriberi - a deficiency of the B vitamin, thiamine, causing inflammatory or destructive changes of the nerves, digestive system, and heart

bile - alkaline fluid secreted by the liver to help digest fat

biochemical oxygen demand (BOD) - the amount of oxygen required to oxidize a given amount of organic material

biochemical reaction - a chemical reaction or process that takes place within a living organism

biodegradable - capable of being broken down by biological processes into basic components, usually by microorganisms or by enzymatic action

biofeedback - a technique used to help people relax. In biofeedback, a person is connected to a machine that senses and records one or more of the bodily functions and feeds this information back to the person, who then tries to manipulate those bodily functions by conscious mental control

biogeochemical cycle - the processes by which a mineral is recycled through the environment

biological control - methods of controlling pests by introducing and encouraging natural predators or of reducing the harmful effects of a pest population in some biological way

birth control - various methods used to prevent pregnancy

blanching - heating of vegetables to stop enzyme action

blast-freezing - a method of quick freezing food by blowing air at -15o to -20oF across it with a high-speed fan

boiler - a network of metal tubes in which water is heated to steam

boiling point - the temperature at which the vapor pressure of a liquid exactly equals the pressure above the liquid, example, the point at which the liquid has entered the gas phase

bolus - a small round mass or lump; referring to food as it passes from the mouth to the stomach

bonds - attractive forces that hold atoms and ions together in molecules

botulism - a severe form of food poisoning from food containing a toxin produced by the bacterium, Clostridium botulinum

bovine - relating to, or resembling the cow

Boyle's Law - the volume of a fixed mass of gas varies inversely with the pressure at a constant temperature

breed - to produce plants or animals sexually and usually under controlled conditions

breeder - anyone who raises animals or plants for propagation

British Thermal Units (BTU) - the quantity of heat required to raise the temperature of one pound of water by one (1) degree Fahrenheit

bronchioles - branching airways in the lungs

browning - the darkening of food with exposure to air

buffer - a substance that helps to control the pH of a solution

bulimia - a neurotic disorder characterized by bouts of overeating followed by voluntary vomiting, fasting, or induced diarrhea

bulk flow - the movement of water in mass within plants and animals

butyl nitrite - a type of inhalant. Also known as "locker room," "rush," and "jacoroma," this drug is a liquid that comes in a small bottle; the vapors are inhaled.

caesarean section - delivery of an infant through an incision in the abdominal and uterine walls

caffeine - a mild, legal stimulant found in many foods and drinks, such as coffee, tea, cola drinks, and chocolate.

calibrate - to check, adjust, or standardize the graduations of a measuring instrument

calorie - the amount of heat energy required to increase the temperature of one gram of water by one degree Celsius

Calorie - a unit of heat used in human nutrition equal to one kilocalorie; used to express heat-producing or energy-producing value in food when oxidized in the body

cancer - the uncontrolled growth and spread of abnormal cells

cancerous - relating to an enlarged tumor-like growth that contains cancer cells

capillaries - small, thin-walled blood vessels through which substances are exchanged between blood and tissues

carbohydrates - organic compounds containing only carbon, hydrogen, and oxygen (as sugars, starches, and celluloses) most of which are formed by green plants and which constitute a major class of animal foods; the body's main source of energy. They are divided into major types; simple sugars (disaccharides) and complex carbohydrates

carbon cycle - a description of the circulation of carbon through the environment, mainly as a result of life processes

carbon dioxide-oxygen cycle - the processes by which carbon dioxide and oxygen gases move through the environment

carbon monoxide - a by-product of tobacco smoke and other types of combustion. Carbon monoxide binds to hemoglobin in red blood cells, thus blocking the site where oxygen molecules would normally be carried in the red blood cells and depriving the user of oxygen.

carboxylic acid group - the function group responsible for the acidic characteristics of certain weak acids such as vinegar; -COOH

carcinogen - agent involved with the onset of cancer (chemicals, radiation) and accelerates its development

carcinoma - cancers of the tissues covering body surfaces and lining most body cavities (epithelial tissue). Example of carcinomas include breast, lung, skin, and mouth cancer.

cardiac care unit (CCU) - the hospital section devoted to caring for patients with heart problems

cardiovascular - related to the heart and blood vessels

carnivores - animals whose diet is composed primarily of nonplant material - fish or meat

carrier - a bearer or transmitter of a causative agent of disease; especially one to which the carrier is immune

catalyst - any substance that increases the rate of a chemical reaction but is not altered in the reaction

cataract - clouding of the lens of the eye or of the overlying transparent membrane, creating an opaque area in a person's visual field

cation - any atom or group of atoms with a positive charge

cecum - a blind pouch that forms the first portion of the large intestine

cell - structural unit of an organism, in most cases visible only with a microscope

cell membrane - structure that separates the components of a cell from its environment and regulates the passage of materials into and out of the cell

cellulose - a complex carbohydrate found in stems, bark, and fibrous parts of plants, not digestible by animals

centrioles - a pair of organelles that play an important role in the division of animal cells

cervix - hollow, narrow, neck area of the uterus leading to the vagina

characteristic - a distinguishing trait, quality, or property

Charles' Law - the volume of a fixed mass of gas varies directly with the absolute (Kelvin) temperature at a constant pressure

chemical bond - a force of attraction between two atoms that represents the storing of chemical energy

chemical dependency - dependence on a drug or drugs

chemical equilibrium - the condition in a chemical reaction in which the reactants are converting to products at the same rate the the produces are converting back to reactants

chemical formula - a description of a molecule that shows the type and number of atoms it contains

chemical reaction - changing of substances to other substances by breaking existing chemical bonds and forming new chemical bonds

chemotherapy - type of cancer treatment that uses over 50 different drugs or chemicals to kill cancer cells

chlorofluorocarbons - group of compounds used as refrigerants, cleaning solvents and previously as aerosol propellants; harmful to the ozone layer

chlorophyll - pigment used by plants to absorb sunlight during photosynthesis

cholesterol - a type of lipid that builds up on the walls of blood vessels, narrowing the channels through which blood flows

chorionic villi sampling - study of extra-embryonic cells making it possible to determine genetic errors in the embryo

chromatid - a copy of a chromosome

chromatin - mass of material inside the nuclear membrane the appears as chromosomes during cell division

chromosomes - distinct bodies in the nucleus containing DNA that appears during cell division and contain genes; in bacteria, a long circular strand of DNA in the cell

chronic - referring to illnesses that have no real cure and that are of long duration and often get worse over time

chyme - the mass of partly digested food expelled by the stomach into the small intestine

cilia - a short, hair-like structure on the cell surface involved in movement

circulatory system - system of blood, blood vessels and heart

clear-cutting - the practice of removing all vegetation in a given area, leaving the soil with no support

clitoris - a highly sensitive organ located at the front of the urethral opening in female mammals

clone - a group of genetically identical organisms

coagulation - the formation of a liquid into a semisolid or solid mass

cocaine - a stimulant made from the leaves of a South American coca plant. It comes as a paste added to tobacco; as a powder (cocaine hydrochloride) inhaled through the nose or injected when mixed with water; purified (freebase) by mixing cocaine powder with ether, baking soda or other solvents to remove everything but the pure cocaine; or as crack--freebase made into ready-to-smoke rocks

codeine - a narcotic alkaloid, C18H21NO3, derived from opium or morphine

codon - a sequence of three bases in messenger RNA which represent a certain amino acid

coefficient of digestibility - percentage value of a food nutrient that is absorbed

colic - acute abdominal pain localized in a duct or cavity of the body caused by spasm, obstruction, or twisting

colligative properties - properties such as vapor pressure and freezing point that are determined by the number of solute particles in a solution rather than by the chemical properties of the solute

colloidal suspensions - small particles in a liquid that are kept permanently suspended

colon - the major part of the large intestine, extending from the cecum to the rectum

colorimetric test - a method of chemical analysis in which the color of a solution is compared to standard colors representing known values

combustion - the rapid combining of fuel with the oxygen in the air; the process by which fuel is converted to heat

complementary - relating to the precise pairing of bases between two strands of DNA and sometimes between one strand of DNA and a strand of RNA

complex carbohydrates - compounds composed of straight or branching chains of sugar units (starches, cellulose); they provide the body with energy for a longer period of time than simple sugars

composting - the mixing of organic matter and other materials into soil to speed up their decay into nutrients

compound - two or more different elements joined together by chemical bonds

compress - to reduce in size or volume

concentration - number of molecules or atoms of a substance relative to the space that the substance occupies

condense - to change from gaseous state to liquid state; such as, when water vapor condenses to form water

condensing point - the temperature at which the gas phase of a substance will form into a liquid

condom - thin rubber sheath worn by males to prevent semen from entering the vagina of the female during intercourse

conduction - the process in which heat energy flows from an area of higher temperature to an area of lower temperature

congenital - existing at or dating from birth

congenital defect - an abnormality existing at or dating from birth

congestive heart failure - heart failure occurring when blood builds up in the heart, which happens because the heart is damaged and cannot pump properly

consumptive - the use of any resource in a way that harvests and destroys it

contamination - the process of making impure, usually with either unwanted substances or microorganisms

contraception - voluntary prevention of fertilization or implantation of a fertilized egg

contraction - the shortening and thickening of a functioning muscle or muscle fiber as in the uterus in preparation for delivery of a baby

Controlled Substances Act - the Congressional act classifying and restricting dangerous drugs on the basis of accepted medical use

corpus luteum - hormone-producing mass that forms in a ruptured ovarian follicle after the release of the egg

corrosive - a substance that gradually oxidizes or otherwise destroys metals

cosmic radiation - a stream of ionizing radiation of extraterrestrial origin; chiefly of protons, alpha particles, and other atomic nuclei but including some high-energy electrons and photons

cross breeding - to interbreed two varieties or breeds within the same species

crude protein - a mixture of true protein and nonprotein nitrogen in a food. It indicates the capacity of a feed to meet an animal's protein needs

cultivation - growing or raising of organisms, usually vegetable crops, by domestic means

cultural - relating to the socially transmitted behaviors of a group of people

cytologist - a person who studies structure, function, multiplication, pathology, and life history of cells

cytoplasm - the watery fluid or gel outside the nucleus of a cell

cytosine - one of the nitrogenous bases in DNA or RNA

cytotechnologist - a medical technician trained in the identification of cells and cellular abnormalities (as in cancer)

deficiency - a lack; less than the normal amount

deforestation - process of clearing forests, usually for the sake of agriculture

degradation - lowering the quality of a resource, polluting it

dehydration - removal of water from a substance; condition resulting from excessive loss of body fluid

delirium tremens - a symptom of severe alcohol withdrawal; characterized by confusion, delusions, and dramatic hallucinations.

density - mass per unit of volume of a substance

deoxyribonucleic acid (DNA) - organic molecules that make up the chromosomes of cells and contain genetic information in the form of a chemical code

depletion - using up of the total quantity of a resource

depressant - serving to lower the rate of vital activities

dermatitis - inflammation of the skin

designer drugs - substances that produce effects similar to those of existing illegal drugs

diabetes - a disease often caused when the pancreas fails to produce insulin, thereby preventing sugar from getting to the body's cells and depriving them of energy

diabetic - person with a deficiency of insulin causing glucose to remain in the blood instead of entering the cells where it is metabolized

dialysis - the passage of a dissolved substance through a membrane

diaphragm - sheet-like muscle that separates the abdominal and thoracic cavities; helps draw air into the lungs; a rubber cup used as a birth-control device that is inserted by the woman to prevent sperm from reaching the uterus and oviducts

diarrhea - frequent passage of unformed watery bowel movements

diatomic atoms - - those atoms which exist in nature (molecules) with with two atoms in a molecule; Hydrogen (H2), Oxygen (O2), Nitrogen (N2), Fluorine (F2), Chlorine (Cl2), Bromine (Br2) and Iodine (I2)

dietary fiber - components of food that are resistant to chemical digestion

diffusion - net movement of molecules in a dissolved or suspended substance due to the energy of the molecules themselves

digestible energy - that portion of the gross energy in a feed that is not excreted in the feces

digestion - process of breaking large molecules into smaller ones by chemical and/or physical means

diglycerides - a type of lipid molecule (glycerol molecule combined with two fatty acid molecules)

dilate - to enlarge or expand, especially the diameter of an opening

dilute - said of a solution with a small amount of solute; to make a solution less concentrated by adding additional solvent

disaccharides - carbohydrates containing two molecules of sugar. Examples are sucrose (common table sugar) and lactose (found in milk products).

disinfectant - agent that will kill microorganisms on nonliving objects

disperse - to spread out or scatter

dissociate - the breaking (separating) of molecules, usually into positive and negative ions; example, common table salt NaCl into Na+ and Cl-

dissolved oxygen concentration (dO2) - the amount of oxygen gas (O2) dissolved in water, usually measured in milligrams per liter of water or parts per million of oxygen to water

dissolving - the process of forming a mixture of 2 or more substances that is the same throughout. One component of the mixture is the solvent and there is more solvent in the mixture than any other component. The other components of the mixture are called the solute and can be solid, liquid, or gas.

diuretic - a substance that tends to increase the flow of urine

diversity - relates to the enormous variety of traits within biological species or the great overall number of species present on Earth

diverticulosis - disorder of the colon due to a weakening of the muscle lining where the inner wall of the colon develops pouches which may later become inflamed

DNA fingerprinting or profiling - analyzing DNA sequences of individuals and matching them to other DNA samples

DNA sequence - the order of bases in a part of a DNA molecule

dominant trait - said of a gene or hereditary trait which is expressed regardless of the presence of other (recessive) genes

Down's syndrome - a congenital condition caused by a chromosome abnormality that leads to mental retardation

ecosystem - a biological community (plants, animals, and other organisms) and the nonliving parts of an environment with which it interacts

ecstasy - a type of hallucinogenic designer drug

egg - female reproductive cell produced in the ovaries; ovum

ejaculate - to expel semen from the penis

electrocardiogram - a graphic tracing of heartbeats recorded by an instrument called the electrocardiograph. The tracings indicate the electrical impulses transmitted by the heart muscle both during and between heartbeats

electrode - terminal that conduct electric current or that emit, collect, or control the flow of electrons

electrolytes - ionized salts in the blood, tissue fluids, and cells, especially ions of sodium, potassium, and chlorine

electron - a negatively charged particle found outside the nucleus of an atom

electron microscope - a microscope that uses a beam of electrons to produce an image of an extremely small object or field of vision

electrostatic precipitator - a device that traps particles in industrial waste gas by attracting them to electrically charged plates

element - one of the basic substances that make up the world and determine the characteristics of all material; substances that cannot be separated into different substances by chemical processes. Elements can be changed to other elements by radioactivity or nuclear reactions

embolus - a blood clot that breaks off from one area and wanders to another

embryo - a developing plant or animal contained inside an egg or nourished inside the female parent after fertilization

embryo transplant - transferring an embryo from the womb of its mother to the womb of another female in which it completes its development

embryonic period - the first two months of pregnancy in a human

emergency medical technician (EMT) - a member of a pre-hospital emergency care team. The EMT administers first aid at the scene of an accident or acute attack of an illness and transports sick or injured persons to the hospital

emission gas recycler - a device that returns the exhaust gases of an internal combustion engine to the combustion chamber for more efficient burning of fuel

empirical formula - the simple ratio of the number of atoms of elements in a compound

emulsifiers - a substance capable of breaking up fatty substances into small particles that can be suspended in a fluid and not settle out

emulsion - suspension of one liquid in another liquid

endangered species - a species with so few living members that it soon will become extinct unless measures are begun to slow its loss

endocrine glands - glands that secrete substances into the blood or lymph to regulate or control bodily functions

endocrine system - the system of hormone-secreting glands in the body

endometrium - the uterine lining; is shed at the start of each menstrual cycle

endorphins - chemicals released into the bloodstream during exercise that induce a relaxed, pain-free state of mind, possibly helping to relieve depression

energy - the ability to do work

enrichment - the addition of vitamins or minerals to a food from which vitamins or minerals were lost during processing

ensilage - placing grains or chopped forage in airtight silos and allowing them to ferment

enzyme - a specialized protein molecule that speeds up the rate of chemical reactions, such as the breakdown of food to release nutrients; a biological catalyst

epidemic - a large outbreak of a disease

equilibrium - to maintain a balance

equivalent - the weight of solute that will supply one mole of reacting material in a solution

erosion - loss of soil from an area because of flooding, wind, or rainfall

esophagus - a muscular canal extending from the pharynx to the stomach; essential for carrying swallowed food and liquids from the mouth to the stomach

essential amino acids - amino acids required for metabolism and growth; that must be supplied in the diet because they are not synthesized in the body

estrogen - female sex hormone

estrous - time during which some female mammals can be fertilized; also called "heat"

ethnic - relating to large groups of people classed according to common racial, national, religious, or cultural origin or background

eutrophication - a part of the normal aging process of lakes in which they become enriched with nutrients, and silt and organic matter settle out, filling them up

evaporation - the change of liquid water into water vapor

evapotranspiration - movement of water to the atmosphere by evaporation from soil and surface water and by transpiration from plants

external fertilization - fertilization of the eggs outside the female body

extinct - no longer an existing form of life

extinction - the dying out of a species

fats - lipids composed of fatty acids and glycerol, including mono-, di-, and triglycerides; present in greases, oils, butter

fatty acids - building blocks of fat molecules

fermentation - partial breakdown of carbohydrates, often by microorganisms

fertilization - production of the first cell of a new individual by the union of a sperm with an egg

fertilizer - a substance or mixture of substances used to make soil more suitable for supporting life

fetus - a developing human from week eight of pregnancy until birth

fiber - a type of complex carbohydrate that plays a critical role in moving foods through the digestive tract

fibrillation - a condition in which the heart beats in a random pattern

finishing - concentrating an energy source in the feed of the slaughter animal to distribute fat within the body tissue

fission - asexual reproduction in which one organism divides into two small organisms of equal size

flammable - anything that can ignite easily and burn quickly

floc - a fluffy mass formed by the clustering of suspended particles

fluid - a substance that is able to flow. Air and water are both fluids

follicle - a tissue within an ovary; site of development of the egg before it is fertilized

follicle-stimulating hormone (FSH) - hormone that stimulates the ripening of eggs in follicles of the ovary; hormone that stimulates sperm production in males

food additive - any substance that becomes a part of a food product "intentionally, unintentionally, or incidentally"

food irradiation - a type of processing where beams of ionizing energy penetrate the food and destroy microorganisms that cause disease and spoilage

food pyramid - a graphic representation of a biological community in terms of the number of organisms present (or their total mass or value in calories)

food web - the network of food relationships in a community of organisms; the connections of who eats whom

forages - plants grown for their leaves, stems, and roots and used as animal feed

fortification - addition of vitamins and/or minerals to foods to supplement their normal nutritional value

fossil fuel - hydrocarbon compounds derived from the buried remains of organisms (plant and animal remains)

foundering - inflaming of a horse's hoof accompanied by pain and lameness

fraternal twins - twins that develop when two different eggs are fertilized by two sperm

free atoms - (unbonded atoms) atoms which are not united with other atoms

free radicals - highly reactive atoms that have one or more unpaired electrons

freezing point - the temperature at which a liquid becomes a solid

fructose - a type of simple sugar or monosaccharide. Fructose is found in fruit and berries

fungi - a large group of microscopic organisms including molds and yeasts that feed by absorbing substances from their habitat and reproduce by means of spores

fungicide - an agent that kills fungi and their spores

fungus - a plant-like organism lacking chlorophyll

galactose - a monosaccharide; composed of a single sugar unit; other examples are glucose and fructose

gallbladder - a pear-shaped sac in the upper abdomen that stores bile from the liver and releases it periodically to the small intestine

gas - a phase of matter with no definite shape or volume

gas spectrophotometry - technique used to measure which wavelengths of visible light are transmitted by a substance in its gas phase

gastrointestinal - pertaining to the digestive tract, especially the stomach and intestine

gene - a functional hereditary unit that occupies a fixed location on a chromosome, has a specific influence on phenotype, and is capable of mutation to various allelic forms

generation - the average span of time between the birth of parents and that of their offspring

generator - machine that converts mechanical energy to electrical energy

genetic - inherited from one's parents

genetic defects - abnormality usually caused by a mutation of a gene; often caused by recessive genes

genetic engineering - altering an organism's genetic makeup by the transfer of genes

genetics - science of heredity

genetic trait - a characteristic of an organism that is inherited from its parents

genotype - particular combination of genes of an organism

geothermal - superheated water and steam that are produced by volcanic action under the surface of the Earth

geriatric - related to aging; of or for older adults

germicide - an agent that kills microorganisms

germinate - the sprouting of seeds or spores

gestation - in mammals, the length of time from conception to birth

global warming - the current increase in the Earth's average temperature due to the effect of increased CO2 (greenhouse gas) levels in the atmosphere. These increased levels enhance the greenhouse effect

glucose - a type of sugar abundant in corn syrup, honey, vegetables, and certain fruits; a type of simple sugar or monosaccharide

glycogen - a complex carbohydrate used for energy storage in animal tissue

goiter - an enlargement of the thyroid gland

golgi bodies - organelles that function in storage, modification, and packaging of certain proteins

grains - the seed or seedlike fruit of grasses such as corn, wheat, and oats

Gram stain - a type of color staining performed on bacteria to identify the bacteria responsible for an illness

gravity - the attraction of Earth, or another planet, for objects on or above its surface

greenhouse effect - the trapping of heat close to the Earth by CO2 in the Earth's atmosphere

gross energy - the total combustible energy in a feedstuff

groundwater - water that is found below the Earth's surface

guanine - one of the nitrogenous bases in DNA and RNA

guard cells - pairs of cells that control the opening and closing of pores (stomata) leading to the internal tissues of the plant

gynecology - a branch of medicine that deals with the diseases and hygiene of women

habitat - the physical environment in which an organism lives

hallucinogens - chemicals producing auditory (hearing) and visual (seeing) hallucinations in users

halon - a common type of chlorofluorocarbon

hardness - the amount of a salt, usually calcium carbonate, dissolved in water

hashish - a narcotic extract prepared from the flowers of the hemp plant; hash

heat - thermal energy that passes from a warmer object to a cooler one

heat capacity - the quantity of heat required to change the temperature of one gram of a substance by one (1) degree Celsius

heat content - the number of calories released for each gram of fuel that is consumed

heat of fusion - the amount of heat required to change one gram of a solid into liquid

heat of vaporization - the amount of heat required to change one gram of liquid into vapor

hematology - the study of blood

hemoglobin - an iron-containing pigment in the blood that turns bright red when it binds and transports oxygen; gives blood its color

hemorrhoids - a mass of dilated veins in swollen tissue at the margin of the anus or within the rectum

hepatitis - an orally contracted disease causing inflammation and damage to the liver

herbicide - an agent used to destroy or inhibit plant growth

herbivores - animals whose diet is composed primarily of plant material

heredity - transmission of characteristics from one generation to the next

heroin - a type of opiate with no medical use in the United States and available only illegally. It is sold both as a white powder and as a sticky, black substance. Heroin can be snorted or smoked, but usually it is injected beneath the skin or into a vein.

heterozygous - having different genes for a given trait such as one dominant gene and one recessive gene

hiatus hernia - protrusion of the upper part of the stomach into the chest cavity; associated with increased acidity in the esophagus

high-density lipoprotein (HDL) - a compound in the blood that transports cholesterol to the liver for metabolism and elimination from the body. HDLs are efficient transporters of cholesterol.

histology - the study of tissues

HIV (Human Immunodeficiency Virus) - the virus responsible for AIDS

homogeneous - said of a mixture that is the same throughout

homozygous - having identical genes for a given trait

hormones - a chemical regulator that is produced in glands and affects other parts of the body; a chemical messenger

host - on organism that provides nourishment and/or shelter for a parasite or pest

human chorionic gonadotrophin (HCG) - hormone secreted by cells surrounding the embryo during implantation

humidity - the amount of water vapor in the air

humus - decaying organic matter making up topsoil

Huntington's disease - Huntington's chorea; a genetic disorder that is caused by a dominant gene that causes deterioration of the nervous system after about age 35

hybrid - an organism that inherits from its parents some characteristic that is different from either of the parents

hydrocarbon - a compound made only of atoms of hydrogen and carbon

hydrogenated - a compound to which hydrogen atoms have been added

hydrogen bonds - an essentially ionic chemical bond between a strongly electronegative atom and a hydrogen atom already bonded to another strongly electronegative atom

hydrolysis - the decomposition of a chemical compound by the reaction with water

hydronium ion (H3O+) - a cation formed when water ionizes or when acids are added to water

hydroxide ion (OH-) - an anion formed when water ionizes or when bases are added to water

hygroscopic - readily taking up and retaining moisture

hymen - a thin membrane that partially covers the vagina and can be broken by physical activity, use of tampons, and sexual intercourse

hyperlipidemia - excessive quantity of lipids in the blood

hypersensitivity - an extreme reaction to certain antigens by the body's immune system. Hypersensitivity is responsible for many allergies

hypothalamus - a gland at the base of the brain that sends messages to other endocrine glands; function in the maintaining of constant internal body conditions

hypothesis - a temporary explanation put forth to explain observations and events and then tested in some way to see if it is valid

identical twins - twins that have the same genotypes, resulting from the splitting of a zygote and development into two separate embryos

immune system - the body's system for destroying invaders. It includes white blood cells, such as macrophages and lymphocytes

immunological memory - the ability of antibodies to recognize an antigen after the first exposure

implantation - attachment of the embryo in the uterine wall

inbreeding - mating of closely related or genetically similar individuals

incubation - maintaining organisms under conditions favorable to their development

inert - unable to react

infectious disease - any contagious disease caused by pathogens, which are organisms that enter the body and cause it to be sick

inflammation - a local response to injury including increased blood flow, redness, pain, and tissue swelling

inhalants - chemicals that give off vapors that produce highs when inhaled

inheritance - the reception of genetic qualities by transmission from parent to offspring

inoculate - the introduction of a microorganism into the body or a special culture medium

inorganic - a chemical compound that does not contain carbon as a principle element (exceptions are carbonates, cyanides, and cyanates)

in-process recycling - removing waste material at a particular point in an industrial process and retuning them for use somewhere in that process

insecticide - an agent used to exterminate insects

insomnia - chronic inability to obtain adequate sleep

insulin - a hormone produced by the pancreas that allows sugar to enter the body's cells

integrated pest management - the planned use of multiple solutions to pest problems. Solutions usually include biological controls and some degree of pesticide use.

interaction - mutual or reciprocal action or influence

internal fertilization - fertilization of the egg inside the female body

intestine - that portion of the digestive tract in humans which extends from the stomach to the anus; divided into two sections, the small intestine and the large intestine (colon)

intrauterine device (IUD) - a small piece of plastic or plastic and metal that is inserted in the uterus by a physician; prevents implantation of the fertilized egg in the uterus

in vitro fertilization - means "in glass" fertilization; fertilization of the egg in a laboratory; also known as test-tube fertilization

ionization - the dissociaton of certain molecules into positive and negative ions

ionization of water - the dissociation of some molecules in a sample of water into H3O+ and OH- ions

ionizing radiation - energy which, when it strikes a molecule, splits the molecule into charged particles called ions

ions - atoms that have a positive or negative charge as a result of having lost or gained one or more electrons

irrigation - the watering of crops with water pumped from underground or piped from surface waters

islets of Langerhans - the insulin-producing cells of the pancreas

isotopes - forms of the same atom but with different atomic mass (because of differences in numbers of neutrons)

jaundice - yellowish pigmentation of the skin, eyes, and body fluids caused by the deposition of bile pigments

karyotyping - photographing and arranging of pictures of chromosomes in a cell according to shape and number

Kelvin scale - a thermometer scale having the same unit of measurement as the Celsius scale; absolute zero is 0oK (273oC)

kidney - an organ in vertebrate animals that functions to maintain proper water balance, regulate acid-base concentration, and excrete soluble wastes as urine

kilocalorie - a unit of measure for heat. In nutrition, a kilocalorie is known as a large Calorie and is always written kc.

kinetic energy - energy involved in producing work or motion

kwashiorkor - severe malnutrition in infants and children that is caused by a diet high in carbohydrates and low in protein

labia majora - the larger of two folds of skin which cover the urethral and vaginal openings

labia minora - the smaller of two folds of skin which cover the urethral and vaginal openings

labor - in a pregnant female, the period from onset of contraction to delivery of a baby

lactation - period during which an animal nurses its young on milk

lactose intolerance - intolerance to the lactose sugar in milk, characterized by gastrointestinal distress

landfill - an area where wastes are buried between layers of earth

laser technology - the study of lasers, the electronic devices which control lasers, and the optical systems which focus and shape the laser's light

leach - extract a substance from a mixture of chemical by rinsing in a solvent in which the substance dissolves

leaching - the loss of plant nutrients from the soil as they dissolve in water that the soil cannot hold; process by which water carries dissolved or suspended materials as it percolates down to groundwater

Le Chatier's Principle - if stress is applied to a system at equilibrium, the system readjusts so that the stress is reduced

legumes - peas, beans, and related plants that can fix nitrogen in their roots with the help of microorganisms

leukemia - cancer of the blood-forming parts of the body, especially the bone marrow and the spleen. It is characterized by an abnormal increase of white blood cells.

lignite - a brownish-black coal of low grade

limited resource - a resource that may be expected to run out some time in the future; for example, petroleum

lipase - digestive enzyme secreted by the pancreas or stomach to break down fat molecules in food

lipids - organic substances that do not dissolve in water (for example, fats, oils, grease). They store energy, carry fat-soluble nutrients, and enhance the taste and texture of foods

liquid - a phase of matter with a definite volume but no definite shape

liver - a complex organ in the body; one of its roles is to secrete bile for the digestion of fats in the small intestine

loam - soil with an equal mixture of sand, clay and silt

logarithm - the exponent that indicates the power to which a number has been raised to produce a given number

low-density lipoprotein (LDL) - a compound in the blood that like high-density lipoproteins, transports cholesterol to the body's cells. LDLs are much less efficient transporters than HDLs, therefore, a higher ratio of LDLs to HDLs is considered unhealthy

LSD (lysergic acid diethylamide) - a type of hallucinogen, also known as "acid." LSD is made as an odorless, tasteless, white crystalline powder dissolved in water to make a solution

lupus - an autoimmune disease with no known cure that can damage the kidneys, lungs, and heart. Its symptoms include fever, joint pain, and skin irritations.

luteinizing hormone (LH) - in female mammals, hormone that causes the follicle to rupture and the ruptured follicle to change to the corpus luteum; causes production of testosterone in the male

lymphatic system - an open circulatory system that gathers excess fluid from the body and drains it into the veins of the cardiovascular system

lymphocytes - white blood cells that form clones of specific antibodies to bind to specific antigens, thus giving the body immunity to that antigen

lymphoma - a cancerous tumor occurring in the lymphatic system, the infection-controlling regions of the body

lysine - one of approximately 20 amino acids involved in protein synthesis

magnetic resonance imaging (MRI) - a technique that gives a computer image of body tissues by inducing their molecules to give off radio waves. It is useful in detecting diseases, such as cancer.

malignant - a tumor that can be dangerous or even fatal by interfering with some vital bodily function

mammal - any vertebrate that feeds its young with milk produced in the mammary glands of the female

Marasmus - progressive emaciation especially in children under-nourished because of a diet deficient in calories and protein

marijuana - the dried leaves and flowers of the female hemp plant, also commonly referred to as "pot," "grass," "weed," "reefer," or "maryjane."

mass - a measure of the amount (quantity) of matter a body possesses

maternal - of or pertaining to the mother

mating - sexual union between a male and a female

mature - to become fully developed

mechanism - a process or technique for achieving a result

median - the value exactly at the midpoint of a series of values

meditation - a relaxation technique. It usually involves sitting in a comfortable position in a quiet place and focusing one's mind on a word, sound, or phrase while breathing deeply and slowly.

meiosis - division of the cell nucleus that reduces the chromosome number of cells by one half; produces gametes in animals

meiotic cell - refers to the egg and sperm; the reproductive cells

melting point - the temperature at which a solid melts to become a liquid

membrane - the outer semipermeable layer of the cell

menstrual cycle - monthly series of hormonal changes leading to egg maturation and uterine preparation for a possible pregnancy

menstruation - shedding of the lining of the uterus in nonpregnant females and characterized by bleeding for a few days each month

mescaline - a type of hallucinogen taken from the peyote cactus (found in the southwestern United States and parts of Latin America). Street names include DOM, STP, TMA, and MMDA.

messenger RNA (mRNA) - RNA that carries the genetic code of DNA; functions in protein synthesis

metabolism - the chemical changes in living cells by which energy is provided for vital processes and activities and new material is assimilated

metabolizable energy - represents that portion of the gross energy of food that is not lost in the feces, urine, and gas

metastasize - the spread of cancer cells in the body

methanol - (CH3OH) wood alcohol or methyl alcohol, produced from the distillation of wood products

micelles - spheres with the nonpolar tails of molecules pointed to the inside of the sphere and with the charged heads of molecules on the surface

microbes - microscopic single-celled organisms including bacteria, yeast, algae, protozoans, etc.

microbiology - the study of microorganisms

microorganisms (microbes) - single-celled organisms too small to be seen by the naked eye such as bacteria, yeast, algae, protozoans, plankton and viruses

MIG welding - a type of arc welding. The letters stand for metal inert gas. This process involves a mixture of gases to provide shielding of the weld from atmospheric oxygen

mineral - an inorganic compound present in the Earth's crust. Rocks are usually combinations of minerals; substances that have a role in a large variety of vital body functions

mitochondria - structures within a cell that are involved in aerobic respiration; release of energy

mitosis - division of cell nucleus resulting in two genetically identical daughter cells

mixture - a combination of two or more substances that are not bonded chemically and that therefore retain their different chemical properties

molar concentration - the number of moles of solute per liter of solution

mold - a type of fungus that grows on the surface of decaying vegetable matter, on fabrics, and even in water

mole - the amount of a substance containing approximately 6 X 1023 particles (atoms, ions, or molecules)

molecular formula - the number of each type of element in a molecule of a compound

molecular weight - the average weight of a molecule of a compound

molecule - the smallest possible form of any compound

monatomic - referring to a single atom or element

monoclonal - same kind of cells; cloned all alike

monoglycerides - lipid molecules containing one fatty acid molecule linked to a molecule of glycerol

monosaccharide - a carbohydrate molecule composed of a single sugar unit (glucose, fructose, galactose)

monounsaturated - fats or fatty acid molecules that have just one region where there is a carbon to carbon double bond

morning sickness - nausea experienced by pregnant women caused by elevated levels of progesterone and estrogen

morphine - a type of opiate available legally by prescription in pill or liquid form

mutagen - any agent that is capable of producing mutations

mutant gene - gene resulting from mutation

mutation - a change in the base sequence of a DNA molecule caused by radiation or chemical agents

myocardial infarction - a heart attack, a blockage of the blood supply to an area of the heart

narcolepsy - a disease that causes a person to drop off to sleep at inappropriate times

natural childbirth - giving birth without the effects of pain-killing medications

natural gas - gas issuing from the Earth's crust through natural openings or drilled wells; a combustible mixture of methane and other hydrocarbons used as a fuel and raw material

natural selection - theory that explains genetic changes occurring in a species over a long period of time

negative logarithm - a notation which gives the logarithm of a number between 1 and 0 a positive value

neonatal - concerning the first six weeks after birth

neutral - a solution in which the concentration of positive and negative ions are equal; a compound that is neither alkaline nor acidic

neutral solution - any solution in which the H3O+ and OH- ion concentrations are equal

neutrons - atomic particles located in the nucleus of an atom which possess no electrical charge; neutrons and protons make up the mass of an atom

nicotine - a powerful central nervous system stimulant contained in tobacco

nitrate - a form of nitrogen (XNO3) that can be absorbed from soil by plant roots

nitrification - oxidation of ammonia or ammonium to nitrites and nitrates

nitrogen cycle - circulation of nitrogen through the environment emphasizing the role of life processes in fixing nitrogen into larger compounds or releasing it as waste

nitrogen fixers - microorganisms which have the ability to convert certain forms of nitrogen compounds into a useful biological substance

nitrogenous bases - one of the three subunits of nucleotides found in DNA and RNA molecules

nitrous oxide - a type of inhalant. Also known as "laughing gas" and "whippets," this gas is used as an anesthetic for dental patients and also as a propellant in cans of whipped cream.

noble gases - a group of stable and unreactive gases that includes helium, neon, argon, and other gases

nonconsumptive - the use of a resource in a way that allows it to be renewed

nonessential amino acids - amino acids that can be produced by the body and are not required in the diet

nonpolar - a molecule having no separation of charges, or having a symmetry of charges about the center of the molecule

nonrenewable - a resource that cannot produce more of itself and is not replaced by natural processes

normality - the number of equivalents (gram equivalent weights - g.e.w.) of solute per liter of solution.

nuclear fission - the process of splitting the atomic nuclei of elements such as uranium to release large amounts of energy

nuclear fusion - the process of joining together the atomic nuclei of elements such as hydrogen to release large amounts of energy

nucleic acid - large, complex molecules (DNA and RNA) that control heredity and cell activities

nucleotide - subunits of nucleic acids containing a sugar, a phosphate, and a nitrogenous base

nucleus - the central core of an atom in which the atom's protons and most of its mass are found; the control center of a cell; surrounded by its own membranes

nutrients - food or any substance that supplies the body with elements necessary for metabolism

obstetrics - branch of medicine that deals with birth

offspring - a new organism produced by reproduction

omnivores - feeding on both animal and plant substances (such as humans and pigs)

oncology - the study of tumors

opiates - powerful central nervous system depressant derived from the opium poppy. Also known as narcotics, they cause euphoric highs followed by depressive lows, as well as relieve pain and lower heart rate, respiration and blood pressure.

opium - a bitter, yellowish-brown, strongly addictive narcotic prepared from the dried juice of unripe pods of Old World poppy containing morphine and other alkaloids

ore - a natural mineral concentration that can be profitably extracted and refined

organ - a group of specialized tissues performing a specific function

organelle - a specialized cell part such as Golgi body, mitochondria and ribosome

organic - a substance in which carbon atoms form the center or "backbone" of its molecules

organism - any living thing that is capable of carrying on life processes

orgasm - muscular contractions along the lining of the male and female reproductive tracts

orthopedics - the treatment or prevention of skeletal deformities

osmosis - diffusion of water across a selectively permeable membrane from an area of greater water concentration to an area of less water concentration

ovary - organ in which eggs are produced

overdraft - groundwater withdrawn over a period of time at a faster rate than it can be replenished

overharvesting - destroying plants or animals of a given species faster than the remaining plants or animals can reproduce

oviduct - a tube leading from the ovaries to the uterus (womb)

ovulation - short stage in the menstrual cycle in which the follicle of the ovary bursts and the mature egg is released

ovum - unfertilized egg; female reproductive cell

oxidant - an oxidizing agent

oxidation - process in which a substance combines with oxygen. Some examples are combustion, rust, and the burning of calories in the body; the loss of electrons by a substance, typically when it combines with oxygen

oxides - compounds of oxygen and other elements

oxidizing agent - any substance that oxidizes another substance (by accepting electrons)

oxygen cycle - circulation of oxygen through the environment emphasizing the role of life processes in taking up or releasing oxygen gas

oxygen demand - the oxygen requirements of a group of aquatic organisms, especially the microorganisms

oxytocin - hormone secreted by the pituitary gland to signal the uterus to begin contractions prior to birth

ozone - an unstable form of oxygen (O3) that may break down into O2 (oxygen gas) plus an extra oxygen atom. Ozone is part of the layer of the atmosphere that protects the Earth from the harmful ultraviolet radiation in sunlight

pacemaker - any of several usually miniaturized and surgically implanted electronic devices used to regulate the heartbeat

palatable - pleasing to the taste

pancreas - an organ in the body located behind the stomach which produces digestive juices (enzymes and buffers), insulin and hormones

parasite - an organism that lives within, upon, or at the expense of another organism, known as the host, without contributing to survival of the host and damages it in some way, usually by causing disease

parasitic worms - the largest pathogens that can infect humans and other animals. They are divided into roundworms such as pinworms, ascaris, and hookworms; and flatworms such as tapeworms.

partial pressure - the pressure exerted by a specific gas in a mixture of gases

particulates - small particles of a substance, especially those suspended in a gas; small liquid droplets or tiny pieces of dust or other solid materials that float in the air

passive solar - use of sunlight to produce heat by maximum exposure of a building to the sun

passive transport - the process of either diffusion or osmosis

pasteurization - heating foods at a temperature that will kill most harmful microorganisms without affecting the quality of the food

paternal - of or pertaining to the father

pathogens - organisms that cause disease in other forms of life

pathologist - person who interprets and diagnoses the changes in the tissues caused by disease

pediatric - of or for children

pedigree - a diagram showing the relationships among a group of genetically related individuals and specifying their phenotypes for various biological traits

pellagra - a disease marked by dermatitis, gastrointestinal disorders, and central nervous symptoms and associated with a diet deficient in niacin and protein

pelvis - basin-shaped structure formed by the bones of the hip girdle growing together

penis - male reproductive organ in animals that have internal fertilization

pepsin - the chief enzyme in gastric juice which begins the breakdown of proteins and release of amino acids into the digestive tract

peptide bond - a chemical bond between the nitrogen of one amino acid and the carboxyl carbon of another amino acid, formed by the elimination of water

percent by weight - weight expressed as the mass in grams of solid solute per 100 grams of solution

percent by volume - weight expressed as the volume in milliliters of a liquid solute in 100 milliliters of solution

percent composition - the most common way of expressing concentration, either as percent by weight (solids) or percent by volume (liquids)

percolate - to cause (fluid) to pass through a porous substance, filter; to pass or ooze through

periodic chart - chart that contains all the known elements, arranged according to their chemical bonding characteristics

periodic table - table that contains all the known elements, arranged according their chemical bonding characteristics

permeability - ability of the cell membrane that allows some molecules to pass but blocks others

peristalsis - muscular contraction which cause food to move along the intestinal tract

persistent - remaining fixed in a specific condition or position; a substance that remains unchanged and is not broken down or degraded in the environment

pest - an organism that has become so abundant that it is threatening the survival of some species that it uses for nourishment or shelter

pesticide - a chemical used to destroy pests, especially insects and rodents

petrochemical - a chemical derived from fossil fuels

pH - a measurement used to express how acidic or basic (alkaline) a substance is

pharynx - the section of the digestive tract (alimentary canal) which extends from the nasal cavities to the larynx, there becoming continuous with the esophagus

phase - a distinguishable part of a regularly recurring cycle of changes

phases of matter - one of three states (solid, liquid, or gas) in which most matter can exist

phenol - a caustic, poisonous, white, crystalline compound drived from benzene and used in various resins, plastics, disinfectants, and pharmaceuticals

phenotype - the environmentally and genetically determined observable appearance of an organism; what it looks like

phosphates - compounds containing the chemical group PO4-3 (a phosphorus atom connected to four oxygen atoms); a primary nutrient form by which organisms take up phosphorus

photoionization - ionization resulting from collision of a molecule or atom with a photon (a particle of light)

photomicrograph - a photograph of a magnified image of a small object

photosynthesis - process by which plants combine water and carbon dioxide in the presence of light and chlorophyll to make carbohydrates for food. Photosynthesis also releases oxygen to the atmosphere

photovoltaic - generation of an electric current by exposing certain substances to light

pH scale - a scale of numbers from 0 to 14 used to indicate how acidic or alkaline (basic) a substance is. A pH of 7 is considered neutral

physiological - characteristic of an organism's healthy or normal functioning

pigment - a compound that absorbs energy in the visible light range

pituitary gland - a small, oval endocrine gland attached to the base of the vertebrate brain, the secretions of which control the other endocrine glands and influence growth, metabolism, and maturation

placenta - mass of small blood vessels and associated tissues across which materials are exchanged between embryo and mother

plankton - microscopic plant-like or animal-like organisms that float or drift in great numbers near the surface of fresh or salt waters

plant extract - substances obtained by separating and processing the juices of various plants

plasmid - circles of DNA found in bacterial cells that are small enough to pass easily from one cell to another, including cells from different species

pneumatic - moved or controlled by air pressure

poacher - someone who kills or takes game or fish illegally

pOH - the negative logarithm of the hydroxide ion concentration in a solution

polar - a molecule having a separation of charges resulting in a positive and a negative region of the molecule

polarity of water - property of water responsible for the bonding of water molecules to one another; the negative end of one water molecule is attracted to the positive end of another water molecule

polar molecule - a molecule which has an identifiable positive and negative region or pole

pollutant - a contaminant released into the environment, especially as a result of human activities

polyatomic molecules - molecules made up of many atoms

polygenes - two or more pairs of genes that affect the same trait in an additive fashion

polysaccharides - complex carbohydrates composed of many sugar units

polyunsaturated - fats or fatty acid molecules that have many carbon to carbon double bonds

population - the total of individuals of one species occupying an area

potential energy - energy that is stored and available for work but is not currently being used to do work

precipitate - a solid that forms when a substance will not further dissolve in the solvent

precipitation - any liquid or solid form of water particles that fall from the atmosphere to the ground. Rain, snow, sleet and hail are forms of precipitation

predator - an organism that kills and eats another organism called its prey

pregnancy - period of development of offspring inside the uterus of a female mammal

preservative - a substance, either natural or synthetic, added to food to prevent it from spoiling

pressure - the force exerted on a given unit of surface; for gases, it may be thought of as the push a gas gives to the side of its container

prey - an organism that is killed and eaten by another organism called its predator

primary nutrient - a nutrient required in large amounts by organisms; includes nitrogen, phosphorous, and potassium

primary wastewater treatment - steps in the treatment of sewage to remove colloids and suspended solids from wastewater

primates - order of mammals that incudes lemurs, monkeys, great apes, and humans

productivity - the amount of bodily tissue that a plant or animal adds to its weight in a certain time period

products - substances formed during a chemical reaction

progesterone - hormone active in the reproductive cycles of female mammals

propellants - gases used to force out the aerosol contents of spray cans

protein quality - the amounts and types of amino acids present in food. Complete protein sources include meat, fish, eggs, milk and dairy products

proteins - carbon and nitrogen-containing compounds made by organisms inside cells to fulfill numerous functions (catalysts, structural molecules, antibody molecules, etc.); compounds containing long chains of building block molecules called amino acids

proton - a positively charged particle in the nucleus of an atom

protozoa - animal-like, single-celled organisms

psilocybin - a type of hallucinogen found in two dozen different mushroom species. Psilocybin is ingested by eating the dried mushrooms.

puberty - the period when an individual first becomes capable of sexual reproduction, marked by the maturing of the reproductive organs, development of secondary sex characteristics and, in human females, the onset of menstruation

purebred - bred from members of a recognized breed over many generations, without introduction of new genes

purge gas - a gas used to displace the volume of a second, unwanted gas

quarantine - isolating materials or living things to determine if they carry parasites or pests

radioactive - a term used to describe a substance that emits streams of subatomic particles as it changes to a stable form

rancidity - having a disagreeable smell or taste from partial decomposition

Rankine scale - an absolute temperature scale on which the unit of measurement equals a Fahrenheit degree

reactants - substances that combine in a chemical reaction to produce products

reagent - a substance used in a chemical reaction to detect, measure, or produce other substances

recessive trait - form of a trait that is sometimes not expressed if a dominant gene is present

recharge zone - the land above an aquifer through which water seeps to the aquifer

recharging - the process by which an aquifer is replenished; that is, by seepage of water through the ground

reclamation - the restoring of disturbed land to some usable state

recommended dietary allowances (RDA) - nutrient requirements for humans as established by the National Research Council of the National Academy of Science

recycling - returning a used product to a raw material that can be used to make a new product

red blood cells - hemoglobin-containing cells within the bloodstream that carry oxygen to the tissues; leucocyte

redox - relating to oxidation-reduction reactions

reducing agent - a substance that reduces a chemical compound by donating electrons

reduction - gain of electrons by a substance

regimen - a systematic plan of activities and regulations of diet, sleep, and exercise designed to improve or maintain health

regulator - any device that controls the flow of air

renewable - a resource that can produce more of itself or that can be replaced by natural cycles; for example, trees

replication - doubling of the amount of DNA in a cell

reproduction - process in which new organisms are produced, either asexually or sexually

residual chlorine - the amount of chlorine remaining in water at some time after the water was chlorinated

respiration - process by which organisms get energy from carbohydrates that react with oxygen. Respiration also releases carbon dioxide to the atmosphere; the taking in of oxygen, its utilization in the tissues, and the giving off of carbon dioxide

ribonucleic acid (RNA) - large, complex molecule that works with DNA in carrying out the instructions of the genetic code

ribosome - organelle in the cytoplasm that is the site of protein synthesis

root pressure - another name for the process of osmosis; water moves into an area in which solutes are more concentrated

roughage - indigestible fiber of fruits, vegetables, and cereals, that acts as a stimulant to aid movement of food through the digestive tract

rumen - one compartment of a herbivore's stomach; acts like a large fermentation vat with many microorganisms

ruminant - a herbivorous animal that has a stomach that is divided into several compartments, one of which is the rumen. Ruminants return food from their stomachs to their mouths to chew it more

runoff - water that flows over land after rainfall, snowmelt, or irrigation

salinity - of or containing salt

saltwater intrusion - displacement of fresh water, either surface or ground water, with salt water as a result of the difference in density

sanitize - to kill or reduce to an acceptable level pathogenic or unwanted microorganisms

sarcoma - a cancerous tumor occurring in the middle layer of tissue, such as bones and muscles. Sarcomas spread through the blood.

saturated - said of fats or fatty acids that have no carbon to carbon double bonds

saturated fats - fat molecules that cannot hold any more hydrogen atoms in their chemical structure. These fats usually come from animal sources and are usually solid at room temperature.

scaling - the forming of a precipitate on some surface, such as calcium carbonate forming on the inside of a water pipe

scientific method - the standard procedure used by scientists for conducting research. It has five steps: (1) observation, (2) hypothesis, (3) experimentation, (4) analyzing the results, and (5) drawing conclusions

scrotum - external sac that encloses the testes of a mammal

scrubber - a device that removes gaseous pollutants from the exhaust gases prior to their leaving smokestacks.

scurvy - a disease marked by spongy gums, loosening of the teeth, and a bleeding into the skin and mucous membranes and caused by a lack of ascorbic acid (vitamin C)

secondary sex differences - changes such as voice deepening and development of facial hair in human males; development of breasts in human females

secondary wastewater treatment - sewage treatment done following primary treatment to remove dissolved organic material

secondhand cigarette smoke - tobacco smoke breathed by nearby nonsmokers

sediment - any solid material that settles out of a solution

selective breeding - choosing animals or plants to mate that will produce offspring with desired features

selectively permeable - allowing some molecules to pass through the cell membrane while keeping others out, usually due to the smaller size of those molecules capable of passing through the membrane

self-ionization of water - the dissociation of some molecules in a sample of water into H3O+ and OH- ions

semen - a combination of sperm cells and fluid that protects and nourishes them

semiconductor - a solid whose electrical conductivity is between that of a conductor and that of an insulator

semipermeable - permeable to some usually small molecules but not to other usually larger particles

senility - a disease of the elderly that causes memory loss with judgment and orientation problems. Senility results from brain cell damage the either occurs gradually over time or is the product of some traumatic incident such as a stroke.

sex chromosomes - chromosomes (X and Y) that determine sex in humans and many other species

sex hormones - testosterone in the male; and estrogen and progesterone in the female

sexual - requiring mating between different sexes; union of egg and sperm

sexual intercourse - involving penetration of the vagina by the penis

sexually transmitted disease - a disease transmitted by sexual contact

sibling - a brother or sister

sickle-cell anemia - hereditary disease in which hemoglobin is abnormal and red blood cells are shaped like sickles

sickle-cell trait - an inherited blood condition in which some red blood cells tend to sickle but usually not enough to produce anemia

silage - fodder converted into moistened feed for livestock through the processes of anaerobic acid fermentation

simple sugar - a type of carbohydrate found mostly in fruits. Simple sugars, such as glucose, provide the body with short bursts of energy

simulation - a model or imitation of how a system functions

sleep apnea - a condition in which breathing stops temporarily during sleep

smog - a mixture of smoke, water droplets, and gases trapped near the ground

sodium hydroxide - an alkaline (basic) substance having the formula NaOH

soil absorption - the ability of the soil to retain (soak up) certain substances such as water and dissolved material

soil conditioning - modifying the soil to enhance plant growth

soil horizon - a layer of soil with characteristic features

solid - a phase of matter with a definite volume and shape

solubility - the amount of a substance that will dissolve in a given amount of another substance

solute - the molecules of a substance that is being dissolved

solutions - mixtures in which one substance (solute) is being dissolved and the other substance is the dissolving medium (solvent)

solvent - a substance used to dissolve another substance

species - a group of organisms that share a set of characteristics, which are passed to their offspring

specific dynamic action (SDA) - the amount of energy used to digest, absorb and process protein, carbohydrates and fat

specific heat - the amount of energy required to raise the temperature of one gram of a substance by one degree Celsius

spectrophotometry - a method of analyzing a chemical sample based on the amount of light of different wavelengths it absorbs

sperm - male reproductive cell found in the testes

spermicide - a chemical inserted into the vagina to kill the sperm

sphincter - a circular muscle which when contracted closes off the passage of substances through a tube; such as in the intestinal tract; cardiac sphincter, phyloric sphincter and anal sphincter

spontaneously - occurring without the help of an external agent

spore - a reproductive cell produced by plants and some protozoans

stable - not readily altered in chemical makeup or physical state

standard - something established as a model or example

staphylococcus - any of various spherical parasitic bacteria occurring in grapelike clusters and causing boils, septicemia, and other infections

starch - a type of complex carbohydrate obtained from plants, and an important source of nutrients for animals that eat plants

sterilization - killing all microorganisms including viruses and spores; a surgical procedure that renders the organism incapable of producing or releasing viable sperm or eggs

stimulant - food, drug, medicine, etc., that temporarily increases the activity of some part of the body; tea, coffee, and alcoholic drinks are stimulants

stock rotation - keeping the older items at the front of a display to sell the products while they are still fresh

stomata - the tiny pores in the surface of a leaf or stem through which gases (including water vapor) are absorbed or released

stratosphere - the part of the atmoshere above the troposphere

stroke - a condition occurring when the blood flow to the brain is blocked, also called a cerebrovascular accident

structural formula - the number of atoms of each element and their arrangement in the molecule of a substance

structure - the arrangement of particles or parts in a substance or body

subsidence - sinking of a part of the Earth's crust due to removal of underground materials

subsoil - a layer of soil below topsoil and above bedrock. Subsoil lacks nutrients needed by plants

suction pressure - a negative pressure created when water evaporates from the leaves of the plant during transpiration; a negative pressure which pulls up on a column of water in the stems and roots; sometimes referred to as transpiration pull

suppositories - a solid but readily meltable cone or cylinder containing medication inserted into a body passage. For example, spermicide suppositories are inserted into the vagina to kill sperm.

surface water - water that is visible on the Earth's surface

surrogate - an organism that serves as a substitute for another

suspensions - a mixture of solid particles in water that are larger than water molecules and tend to settle out

symmetry - refers to the shape a body possesses

symptom - any perceptible change in the body or its functions that indicates the presence of disease

sympto-thermal (S-T) method - a birth-control method that relies on the BBT and ovulation methods plus observing other bodily symptoms

synchronize - to cause to happen at the same time

syndactylism - a hereditary condition that causes webbing of fingers and toes (normal in some animals)

synthesis - the creation by humans of a new product from other products

temperature - a measure of how rapidly the molecules of a substance are moving about

temperature conformers - organisms whose internal temperature fluctuates with changes in environmental temperature

tertiary treatment - any of various methods used to further purify water or wastewater that has already gone through secondary treatment

testes - male organ in which sperm is produced

testosterone - male hormone that stimulates the formation of sperm and secondary sexual characteristics

test-tube fertilization - see in vitro fertilization

theory - fundamental hypothesis that is supported by extensive experimentation

threatened species - a species that is expected to become endangered if nothing is done to help renew it

thrombosis - a blood clot

thymine - one of the bases in DNA but not in RNA

thyroid - a large gland lying at the base of the neck that produces a hormone (thyroxine) that controls metabolic rate

tidal generation - obtaining energy from the change in levels of high and low tide

TIG welding - a common welding process. The letters stand for tungsten inert gas. This process may involve a single or a mixture of shielding gases

tissue - a group of cells that are similar in structure organized to perform a specific function

titration - a laboratory procedure where a measured quantity of a standard solution is added to an unknown solution until an observable change is seen

tolerance - the ability to withstand certain amounts of a drug

topsoil - the upper most layer of the soil, usually greatly enriched in organic matter

total digestible energy - the sum of the digestible protein, digestible fiber, digestible nitrogen-free extract and digestible fat X 2.25

toxic - poisonous

toxicologist - a person who deals with poisons and their effect and with the problems involved (such as clinical, industrial, legal)

toxin - a poisonous substance of animal or plant origin

trachea - a thin-walled tube of cartilaginous and membranous tissue descending from the larynx to the bronchi and carrying air to the lungs

trait - a biological characteristic

tranquilizer - a type of depressant available either legally from a physician or illegally on the street. Tranquilizers include Valium and Librium.

transfer RNA (tRNA) - RNA molecule that brings amino acids to messenger RNA on the ribosome during protein synthesis

transpiration - the process by which water vapor is released into the surrounding atmosphere by plant leaves

trickling filter - wastewater treatment unit in which microbes absorb and break down organic matter during secondary treatment

triglycerides - lipid molecules containing glycerol with three fatty acids; fats

triplet - sequence of three nucleotides in DNA that specify one amino acid

troposphere - the lowest region of the Earth's atmosphere

tubal ligation - a surgical sterilization procedure in which the female's uterine tubes are tied off, cut, and cauterized

tubules - small tubes (similar to arteries and veins in animals) which transports water and dissolved nutrients from the soil through the roots to the leaves

tumor - an abnormal mass of tissue caused by the uncontrolled growth of a cell whose genetic makeup has been altered

turbidity - a measure of the amount of material suspended in a liquid

turbine - an engine with curved blades that are rotated by a gas or liquid under pressure

ulcer - a break in skin or mucous membrane with loss of surface tissue

ultraviolet radiation - a form of light energy, coming primarily from the sun, that is higher in energy than visible light energy

umbilical cord - structure that contains blood vessels; transports blood between the embryo and placenta

unbonded atoms - (free atoms) atoms which are not united with another atom

unlimited resource - a resource that is not likely to run out in the future; for example, sunlight

unsaturated fats - fat molecules that have room for more hydrogen atoms in their chemical structure. These fats are liquid at room temperature and are usually called oils.

uracil - a base in RNA but not in DNA

urethra - canal through which urine (and in males, sperm) is expelled from the body

uterus (or womb) - thick-walled, muscular organ in female mammals in which the embryo develops

vacuum packaging - a food processing method that removes all the air from the package

vagina - the organ in the female that receives the penis from the male during sexual intercourse

vapor pressure - the pressure exerted by a liquid or solid while in the gaseous (vapor) state

varicose - a vein which is dilated and in which the blood is pooling rather than circulating

vas deferens - the duct carrying sperm from the testes to the urethra in the male

vasectomy - a surgical sterilization procedure in which the male's vas deferens is tied, cut, and cauterized

vegan - vegetarian who does not eat any animal protein

vegetarian - one who lives on a diet made up of vegetables, fruits, grains and nuts. Some vegetarians include animal products (such as milk, cheese and eggs); one who does not eat meat

ventilation - circulation of air

vertebrates - animals having a spinal column

vesicles - small sacs; contain various substances that recently entered the cell, and store newly synthesized molecules

villi - very small protuberances found along the digestive tract which absorb nutrients from the digested food material

viruses - the tiniest of all pathogens. Viruses cannot reproduce on their own and must depend on other cells of life. When viruses attack a cell, they force it to produce new viruses.

visible spectrum - wavelengths of light that we are able to see, as opposed to ultraviolet light, which we cannot see, or the infrared spectrum, which we sense as heat

vitamins - various organic substances that are essential in minute quantities to the nutrition of most animals and some plants

volatile - readily vaporizable at a relatively low temperature; to evaporate or cause to evaporate

water balance - the difference between water gains by an organism (inputs) and water losses from the organism (outputs) over a specific time period. An organism is said to maintain water balance when water inputs equal water outputs

water cycle - the processes by which water moves through the environment, including rainfall, runoff, seepage, and various forms of evaporation

watershed - the total drainage area where water flows to a common point, such as a creek or lake

water solubility - the ability of a substance to dissolve in water

water vapor - water in the gas phase; usually below its normal boiling point

watt - a unit of energy equal to about 860 calories. Amounts of electricity produced are counted in kilowatts (thousands of watts).

wavelength - the distance between two energy peaks of adjacent energy waves; light is energy radiating within a particular range of wavelengths

weathering - breakdown of rocks into soil particles by natural physical or chemical processes

weight - a measure of how much Earth's field of gravity pulls on an object

weld - to unite metallic parts by heating and allowing the metals to flow together

Wellness - good health

Winkler method - a chemical method used to determine the concentration of dissolved oxygen in water sample

X chromosome - one of the sex chromosomes

Y chromosome - one of the sex chromosomes that determines maleness

zoonoses - diseases that can be transmitted back and forth between animals and people

zygote - fertilized egg resulting from the union of a sperm and an egg