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69 Cards in this Set

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  • Back
vaccination the administration of treated microorganisms into humans or animals to induce an immune response
vaccine a substance prepared from killed or weakened pathogens and introduced into a body to produce immunity
vacuole a fluid-filled vesicle found in the cytoplasm of plant cells or protozoans
vagina the female reproductive organ that connects the outside of the body to the uterus and that receives sperm during reproduction
valence electron an electron that is found in the outermost shell of an atom and that determines the atom's chemical properties
valence electron
value a principle or standard that an individual considers to be important
valve a fold of membranes that controls the flow of a fluid
vane the web of a feather; consists of barbs and other structures
vapor pressurethe partial pressure exerted by a vapor that is in equilibrium with its liquid state at a given temperature
vapor pressure
variable a factor that changes in an experiment in order to test a hypothesis
variety a division of a species or of a subspecies
varve a banded layer of sand and silt that is deposited annually in a lake, especially near ice sheets or glaciers, and that can be used to determine absolute age
vascular bundle in a plant, a strand of conducting tissue that contains both xylem and phloem
vascular bundle
vascular cambium in a plant, the lateral meristem that produces secondary xylem and phloem
vascular cambium
vascular plant a plant that has a vascular system composed of xylem and phloem, specialized tissues that conduct materials from one part of the plant to another
vascular plant
vascular system a conducting system of tissues that transport water and other materials in plants or in animals
vascular system
vascular tissue the specialized conducting tissue that is found in higher plants and that is made up mostly of xylem and phloem
vascular tissue
vas deferens a duct through which sperm move from the epididymis to the ejaculatory duct at the base of the penis
vas deferens
vector in biology, any agent, such as a plasmid or a virus, that can incorporate foreign DNA and transfer that DNA from one organism to another; an intermediate host that transfers a pathogen or a parasite to another organism
vector in biology
vector in physics, a physical quantity that has both magnitude and a direction
vegetative part any nonreproductive part of a plant
vegetative part
the growth of plants by some means of asexual reproduction
vegetative propagation
a type of asexual reproduction in which new plants grow from non reproductive plant parts
vegetative reproduction
vein in biology, a vessel that carries blood to the heart
vein in geology, a thin, tubular or sheet like deposit of minerals that fills a fracture or joint in a rock
velocity the speed of an object in a particular direction
vena cava one of the two large veins that carry blood from the body tissues to the heart
vena cava
venation the arrangement of veins in a leaf
vent an opening at the surface of the Earth through which volcanic material passes
ventifact any rock that is pitted, grooved, or polished by wind abrasion
ventral the lower or abdominal part of an organism
ventricle one of the two large muscular chambers that pump blood out of the heart
venule a small vessel that collects blood and that joins with other vessels to form veins
vernal equinox the moment when the sun passes directly above the equator from south to north; day and night are of equal length on the day that the vernal equinox occurs
vernal equinox
vernalization in plants, the exposure of seeds or seedlings to a period of cold
venule in plants
vertebra one of the 33 bones in the spinal column (backbone)
vertebrate an animal that has a backbone; includes mammals, birds, reptiles, amphibians, and fish
vesicle a small cavity or sac that contains materials in a eukaryotic cell; forms when part of the cell membrane surrounds the materials to be taken into the cell or transported within the cell
vessel in plants, a tube like structure in the xylem that is composed of connected cells that conduct water and mineral nutrients; in animals, a tube or duct that carries blood or another bodily fluid
vessel element in plants, one of the cellular components of a xylem vessel
vessel element
vestigial structure a structure in an organism that is reduced in size and function and that may have been complete and functional in the organism's ancestors
vestigial structure
vibrationa repetitive, back-and-forth motion of an object around its rest position
villus one of the many tiny projections from the cells in the lining of the small intestine; increases the surface area of the lining for absorption
viper a venomous snake that has two large, mobile fangs at the front of the mouth
viroid an infectious agent that consists of a small strand of RNA and that causes disease in plants
virology the study of viruses and viral infections
virtual image an image that forms at a point from which light rays appear to come but do not actually come
virtual image
virulent describes a microorganism or virus that causes disease and that is highly infectious
virus a nonliving, infectious particle composed of a nucleic acid and a protein coat; it can invade and destroy a cell
visceral mass the central section of a mollusk's body that contains the mollusk's organs
visceral mass
viscosity the resistance of a gas or liquid to flow
visible spectrum the portion of the electromagnetic spectrum that includes all of the wavelengths that are visible to the human eye
visible spectrum
vitamin an organic compound that participates in biochemical reactions and that builds various molecules in the body; some vitamins are called coenzymes and activate specific enzymes
viviparous an organism whose offspring develop within the mother's body and are born alive
volatile liquid a liquid that evaporates readily or at a low temperature
volatile liquid
volatile substance a substance that evaporates readily or at a low temperature
volatile substance
volcanic ash fine pyroclastic particles, less than 4 mm in diameter, that are blown out from a volcanic explosion; also called volcanic dust
volcanic ash
volcanic bomb a large, individual fragment of volcanic material that acquired a rounded form as it solidified before hitting the Earth
volcanic bomb
volcanic dust fine pyroclastic particles, less than 4 mm in diameter, that are blown out from a volcanic explosion; also called volcanic ash
volcanic dust
volcanic neck a mass of hardened volcanic magma that has remained upright after the surrounding material has been eroded
volcanic neck
volcanism any activity that includes the movement of magma toward or onto the Earth's surface
volcano a vent or fissure in the Earth's surface through which magma and gases are expelled
voltage the potential difference or electromotive force, measured in volts; it represents the amount of work that moving an electric charge between two points would take
voltaic cell a primary cell that consists of two electrodes made of different metals immersed in an electrolyte; used to generate voltage
voltaic cell
volume a measure of the size of a body or region in three-dimensional space
voluntary muscle a muscle whose movement can be consciously controlled
voluntary muscle
VSEPR theory a theory that predicts some molecular shapes based on the idea that pairs of valence electrons surrounding an atom repel each other
VSEPR theory
vulcanization a chemical reaction that causes the cross-linking of rubber with sulfur
vulva the external part of the female reproductive organs