Vital Scientific Terms (M)
Terms in this set (178)
A device that transmits or modified force or motion; any of six or more elementary mechanisms, as the lever, wheel and axle, pulley, screw, wedge, and inclined plane.
Evolution theorized to occur over a long period of time, producing major changes in species and other taxonomic groups.
An instrument for measuring the size and distance of distant objects.
The larger of two nuclei present in ciliate protozoans, which controls nonreproductive functions of the cell, such as metabolism.
A large cell that is present in blood, lymph, and connective tissues, removing waste products, harmful microorganisms, and foreign material from the bloodstream.
Also known as megaspore.
A minute yellowish area located near the center of the retina of the eye, at which visual perception is most acute.
Molten rock material within the Earth from which an igneous rock result by cooling.
A light silver-white metallic element that occurs naturally in compounds and is used in alloys, metallurgy, photography, and fireworks.
An object that is surrounded by a magnetic field and that has the property, either natural or induced, of attracting iron or steel.
The lines of force surrounding a permanent magnet or a moving charged particle.
A force which makes objects float in the air.
Magnetic Line of Force
A line of force in a magnetic field.
Materials that are attracted by magnets.
A part of a magnet. Each magnet has a north pole and a south pole.
Magnetic Resonance Imaging (MRI)
The use of nuclear magnetic resonance to produce images of the molecules that make up a substance, especially the soft tissues of the human body; used in medicine to diagnose disorders of body structures that do not show up well on X-rays.
A plastic tape coated with iron oxide for use in magnetic recording of audio or video signals or to store computer information.
Force of attraction or repulsion due to an arrangement of electrons.
Region of the Earth's magnetic field.
A lens that produces an enlarged image of an object.
A measure of the energy of an earthquake, specified on the Richter Scale.
A large digital computer serving 100-400 users; used mainly by large organizations for critical applications, bulk data processing such as census, industry and consumer statistics, and financial transaction processing.
An infectious disease caused by a protozoa in red blood cells, which is transmitted to humans by the bite of an infected female anopheles mosquito.
Used to describe a tumor that invades the tissue around it and may spread to other parts of the body.
The property of a metal that can be hammered or rolled into sheets.
Any of various warm-blooded vertebrate animals of the class Mammalia, including humans, characterized by a covering of hair on the skin and, in the female, milk-producing mammary glands for nourishing the young.
An X-ray image of the human breast, used to detect tumors or other abnormalities.
The lower jaw of a person or animal, usually containing a single bone.
A brittle grayish-white metallic chemical element found in pyrolusite and rhodonite and used in strengthening steel and alloys.
A manifestation of bipolar disorder, characterized by profuse and rapidly changing ideas, exaggerated sexuality, gaiety, or irritability, and decreased sleep.
Factors or conditions that vary in an experiment.
The portion of the Earth, about 2900 km thick, between the crust and the core; in Anatomy, the cerebral cortex.
A colorless, crystalline, water-insoluble, fatty acid, resembling stearic acid, obtained from lichens or synthetically.
A soft, fatty, vascular tissue in the interior cavities of bones that is a major site of blood cell production.
The property of a body that is a measure of its inertia and is commonly taken as a measure of quantity of matter it contains.
The nearest integer to the atomic weight of a given isotope; equal to the combined number of protons and neutrons in the nucleus.
A large connective tissue cell that contains histamine and heparin and serotonin which are released in allergic reactions or in response to injury or inflammation.
The material substance of the universe that has mass, occupies space, and is convertible to energy.
Either of a pair of bones of the human skill fusing in the midline and forming the upper jaw.
A very contagious acute viral disease with symptoms that include a high temperature, sore throat, and a bright red rash of small spots that spread to cover the body.
A body opening or passage, such as the opening of the ear or the urethral canal.
The amount by which a machine multiples force.
Energy which is released by machines.
A sensory receptor of a nerve that responds to pressure, vibration, or some other mechanical stimulus.
A whitish crystalline powder used to treat nausea and motion sickness.
A dark green fecal material that accumulates in the fetal intestines and is discharged at or near the time of birth.
The region in mammals between the pleural sacs, containing the heart and all of the thoracic viscera except the lungs.
The science of diagnosing, treating, or preventing disease and other damage to the body or mind; any drug or other substance used in treating disease, healing, or relieving pain.
The inner core of certain organs or body structures, such as the marrow of bone.
The lowermost portion of the vertebrate brain, continuous with the spinal cord, responsible for the control of respiration, circulation, and certain other bodily functions.
A plant structure in which megaspores are formed, such as those of the female cones of pines.
The larger of two kinds of spore produced by seed plants and some ferns that develops into a female gametophyte.
In organisms that reproduce sexually, a process of cell division during which the nucleus divides into four nuclei, each of which contains half the usual number of chromosomes.
Any of various pigments that are responsible for the dark color of the skin, hair, scales, feathers, and eyes of animals and are also found in plants, fungi, and bacteria.
A dark-pigmented, usually malignant tumor arising from a melanocyte and occurring most commonly in the skin.
A hormone derived from serotonin and secreted by the pineal gland that produces changes in the skin color of vertebrates, reptiles, and amphibians and is important in regulating biorhythms.
The temperature at which a solid changes to liquid.
A think flexible sheet of tissue connecting, covering, lining, or separating various parts or organs in animal and plant bodies, or forming the external wall of a cell.
The storing of learned information, and the ability to recall that which has been stored; a unit of a computer that preserves data fore retrieval.
The first menstrual period.
A synthetic short-lived radioactive chemical element produced by bombarding Einsteinium atoms with Helium particles.
A membrane, especially one of the three membranes enclosing the brain and spinal cord in vertebrates.
A serious, sometimes fatal illness in which a viral or bacterial infection inflames the meninges, causing symptoms such as severe headaches, vomiting, stiff neck, and high fever.
A cartilage disk that acts as a cushion between the ends of bones that meet in a joint.
The time in woman's life when menstruation diminishes and ceases, usually between the ages of 45 and 55.
Abnormally heavy or prolonged bleeding during menstruation.
A heavy, silver-white, highly toxic metallic element, the only one that is liquid at room temperature; quicksilver, used in barometers, thermometers, pesticides, pharmaceutical preparations, reflecting surfaces of mirrors, and dental fillings, in certain switches, lamps, and other electric apparatus, and as a laboratory catalyst.
The instrument most often used to make accurate measurements of atmospheric pressure.
An imaginary line forming a great circle that passes through the Earth's North and South geographic poles.
Embryonic plant tissue that is actively dividing, such as is found at the tip of stems and roots.
The middle embryonic germ layer, lying between the ectoderm and the endoderm, from which connective tissue, muscle, bone, and the urogenital and circulatory systems develop.
The soft tissue (parenchyma) containing chlorophyll between the epidermal layers of a plant leaf.
The region between the stratosphere and the thermosphere, extending from about 32-80 km above the surface of the Earth.
The chemical processes by which cells produce the substances and energy needed to sustain life.
A product of metabolic action.
Any of several chemical elements that are usually shiny solids that conduct heat or electricity and can be formed into sheets, etc.
An element that has some of the properties of both metals and non-metals.
The study of the structure and properties of metals, their extraction from the ground, and the procedures for refining, alloying, and making things from them.
Rock that was once one form of rock but has changed to another under the influence of heat, pressure, or some other agent without passing through a liquid phase.
A profound change in form from one stage to the next in the life history of an organism, as from the caterpillar to the pupa and from the pupa to the adult butterfly.
The second stage of cell division, during which chromosomes line up in preparation for separation.
Philosophical theory supplementing the empirical science of psychology; deals with aspects of the mind that cannot be evaluated on the basis of objective or empirical evidence.
To spread in the body from the site of the original tumor by means of tiny cells transported by the blood or lymph.
The rod-shaped bones in the lower hind limb or hind foot of tetrapods.
The mammalian subclass that contains the marsupials (pouched mammals).
The hindmost of the three divisions of the thorax of an insect, bearing the third pair of legs and the second pair of wings.
A subkingdom of multi-cellular animals whose bodies are composed of specialized cells grouped together to form tissues and that possess a coordinating nervous system.
One of the small bodies of matter in the solar system observable when it falls into the Earth's atmosphere, where the heat of frictions may cause it to glow brightly for a short time.
A meteor that reaches the surface of the Earth.
A specialist who studies processes in the Earth's atmosphere that cause weather conditions.
The science dealing with the atmosphere and its phenomena, including weather and climate.
The international standard unit of length, approximately equivalent to 39.37 inches; an instrument for automatically measuring and recording the quantity of something, as of gas, water, miles, or time.
An odorless, colorless, flammable gas which is the major constituent of natural gas; used as a fuel and is an important source of hydrogen and a wide variety of organic compounds.
A decimal system of units based on the meter as a unit length, the kilogram as a unit mass, and the second as a unit time.
The branch of biology that deals with microorganisms and their effects on other living organisms.
A computer with a microprocessor as its CPU, plus the necessary memory and input and output devices.
A very thin cellular filament that contains protein, found in muscle and the cytoplasm of other cells.
A small opening in the covering of the ovule of a plant through which the pollen tube passes prior to fertilization.
An organism of microscopic or submicroscopic size, especially a bacterium or protozoan.
An integrated circuit that contains the entire central processing unit of a computer on a single chip.
A device that uses a lens or system of lenses to produce a greatly magnified image of an object.
Part of the reproductive structure of certain plants, especially ferns, that produces microspores.
The smaller of two kinds of spore produced by seed plants and some ferns that develops into a male gametophyte.
A leaf that bears a structure by which microspores are formed.
A hollow tubular structure composed of the protein tubulin that helps to maintain the shape and movement of a living cell and the transport of material within it.
A part of the circulatory system made up of the smallest vessels such as capillaries, arterioles, and venules.
A microscopic hair-shaped cell that projects from the surface of the lining of the small intestine, increasing the surface area available for the absorption of nutrients.
The thick central vein that runs from the base of a leaf to its apex.
A person trained to assist women in childbirth.
A recurrent, throbbing, very painful headache, often affecting one side of the head and sometimes accompanied by vomiting or by distinct warning signs including visual disturbances.
The movement of an atom or a group of atoms or double bonds, from one part of a molecule to another.
The spiral galaxy to which the Earth and its solar system belong, some of which appears as a faint band of light in the night sky.
An inorganic solid substance that occurs naturally in rocks and in the ground and has its own characteristic appearance and chemical composition.
An involuntary ending of pregnancy through the discharge of the fetus from the womb at too early a stage in its development for it to survive.
A small round or rod-shaped body that is found in the cytoplasm of most cells and produces enzymes for the metabolic conversion of food to energy.
Divides into two daughter cells, each of which has the same number of chromosomes as the original cell.
The valve between the left atrium and the left ventricle of the heart, consisting of two triangular flaps of tissue, that prevents the blood from flowing back into the atrium.
Matter that consists of two or more substances mixed together but not chemically combined.
An electronic device that makes possible the transmission of data to or from a computer via telephone or other communication lines.
A substance used in a nuclear reactor to slow neutrons to speeds at which they are more efficient in causing fission.
Wetness, especially droplets of condensed or absorbed liquid, or in a vapor.
A large back tooth in humans and other mammals, used for chewing and grinding. Human beings have twelve molars.
The concentration of a solution expressed in moles of solute per liter of solution.
The mass of a molecule in grams per mole, the sum of the component atomic masses; molecular weight.
Any of various fungi that often cause disintegration of organic matter.
The molecular weight of a substance expressed in grams; a small insectivorous mammal living chiefly underground, and having velvety fut, very small eyes, and strong forefeet.
A chemical formula that indicates the kinds of atoms and the number of each kind in a molecule of a compound.
The mass of a molecule in atomic mass units.
A substance whose atoms are held together by covalent bonds.
The smallest physical unit of a substance that can exist independently, consisting of one or more atoms held together by chemical forces.
A large phylum of invertebrate animals (as snails, clams, and mussels) that have a soft unsegmented body lacking segmented appendages and commonly protected by a calcareous shell.
Periodic shedding of part or all of a coat or an outer covering, such as feathers, cuticle, or skin, which is then replaced by a new growth.
A very hard, silver-colored metallic chemical element, used to strengthen steel alloys and found as a trace element in plants and animals.
A measure of the motion of a body equal to the product of its mass and velocity; also called linear momentum.
Having one atom in the molecule.
Producing fruit only once and then dying.
Substance produced by the joining of cancer cells with antibody-producing white blood cells.
A flowering plant that has a single leaf in the seed and floral parts in multiples of three.
A large circulating white blood cell, formed in the bone marrow and in the spleen, that has a single well-defined nucleus and consumes large foreign particles and cell debris.
A plant that has separate male and female flowers on the same plant.
A relatively light, simple organic molecule that can join in long chains with other molecules to form a more complex molecule or polymer.
Relating to a taxonomic group that contains all the descendants of a single common ancestor.
Simple sugar such as glucose or fructose that cannot be broken down into simpler sugars.
A mammal such as the duck-billed platypus or echidna that lays eggs and has a single opening for the discharge of feces and urine.
The only natural satellite of the Earth. It revolves around the Earth in a counter clockwise direction.
The light of the moon which is sunlight reflected to the Earth.
A landform produced by direct deposit of material from the ice of a melting glacier.
The origin and development of an organism or of some part of one, as it grows from embryo to adult.
The branch of biology that deals with the structure of animals and plants.
A loose aggregation of blastomeres resulting from cleavageof the egg of mammals.
The occurrence of genetically distinct cells within tissue or an individual organism.
Small, green non-vascular plant that has stemlike and leaflike parts.
Change in position relative to a frame of reference.
A neuron that conveys impulses from the central nervous system to a muscle, gland, or other effector tissue.
A hand-operated electronic device that controls the coordinates of a cursor on your computer screen as you move it around on a pad; on the bottom of the device is a ball that rolls on the surface of the pad.
In people and animals, the opening in the head and its surrounding lips, gums, tongue, and teeth, through which food is taken in and through which sounds come.
Joints where the adjoining bones are capable of a certain degree of movement.
A viscous, slimy mixture of mucins, water, electrolytes, epithelial cells, and leukocytes that is secreted by glands lining the nasal, esophageal, and other body cavities and serves primarily to protect and lubricate surfaces.
A downhill movement of soft wet Earth and debris, made fluid by rain or melted snow and often building up great speed.
An acute contagious disease, usually affecting children, that causes a fever with swelling of the salivary glands, sometimes also affecting the pancreas and ovaries or testes.
A tissue that is specialized to undergo repeated contraction and relaxation, thereby producing movement of body parts, maintaining tension, or pumping fluids within the body.
Crippling disease characterized by gradual wasting of skeletal muscle.
An external agent, for example, radiation, or some chemicals or viruses, that increases the rate of mutation of cells or organisms.
An animal, cell, organism, or gene that has mutated.
Change in genes or chromosomes that cause a new trait to be inherited.
A relationship between two organisms of different species that benefits both and harms neither.
A loose network of the delicate filaments (hyphae) that form the body of a fungus, consisting of the feeding and reproducing hyphae.
Extremely small parasitic bacteria that lack cell walls and can survive without oxgen; can cause pneumonia and urinary tract infection.
A mutually beneficial association of a fungus and the roots of a plant such as a conifer or an orchid.
Disease of animals caused by fungal infection, e.g., ringworm.
A whitish material made up of protein and fats that surrounds some nerve cells in concentric sheaths, insulating adjacent nerve fibers and enabling transmission of nerve impulses.
Inflammation of the spinal cord or bone marrow.
Structure resembling a thread running through a muscle cell that enables the muscle to contract.
An iron-containing protein resembling hemoglobin, found in muscle cells. It takes oxygen from the blood, releasing it to the muscles during strenuous exercise.
A benign tumor of the muscle tissue.
A visual defect in which distant objects appear blurred because their images are focused in front of the retina rather than on it; nearsightedness.
The most common protein in muscle cells, responsible for the elastic and contractile properties of muscle.
Any of the cells in early embryos that give rise to all the muscles in the body.