Biology Fundamentals Book Vocabulary

ventricle (ven'-truh-kul)

(1) A heart chamber that pumps blood out of the heart. (2) A space in the vertebrate brain filled with cerebro-spinal fluid.

vein

(1) In animals, a vessel that returns blood to the heart. (2) In plants, a vascular bundle in a leaf, composed of xylem and phloem.

vocal cord

A band of elastic tissue in the larynx. Air rushing past the tensed vocal cords makes them vibrate, producing sounds.

ureter (pa-re '-ter or '-reh-ter)

A duct that conveys urine from the kidney to the urinary bladder.

urethra (ya-re'-thruh)

A duct that conveys urine from the urinary bladder to the outside. In the male, the urethra also conveys semen out of the body during ejaculation.

unsaturated fatty acid

A fatty acid that has one or more double bonds between carbons in the hydrocarbon tail and thus lacks the maximum number of hydrogen atoms. Unsaturated fats and fatty acids do not solidify at room temperature.

vestigial structure

A feature of an organism that is a historical rem-nant of a structure that served a function in the organism's ancestors.

water mold

A fungus-like protist in the strarnenopile Glade of the SAR supergroup.

vitreous humor (vit '-re-us hyp "-mei.)

A jellylike substance filling the space behind the lens in the vertebrate eye; helps maintain the shape of the eye.

vacuole (yak'-u-61)

A membrane-enclosed sac that is part of the en-domembrane system of a eukaryotic cell and has diverse functions in different kinds of cells.

whole-genome shotgun method

A method for determining the DNA sequence of an entire genome. After a genome is cut into small fragments, each fragment is sequenced and then placed in the proper order.

virus

A microscopic particle capable of infecting cells of living or-ganisms and inserting its genetic material. Viruses are generally not considered to be alive because they do not display all of the characteristics associated with life.

uniform dispersion pattern

A pattern in which the individuals of a population are evenly distributed over an area.

viroid (vi`-royd)

A plant pathogen composed of molecules of naked, circular RNA several hundred nucleotides long.

vascular plant

A plant with xylem and phloem, including club mosses, ferns, gymnosperms, and angiosperms.

vaccination (vak'-suh-na' -shun)

A procedure that presents the im-mune system with a harmless variant or derivative of a pathogen, thereby stimulating the adaptive immune system to mount a long-term defense against the pathogen.

vesicle (ves'-i-kul)

A sac made of membrane in the cytoplasm of a eukaryotic cell.

vessel element

A short, open-ended, water-conducting and support-ive cell in plants. Chains of vessel elements or tracheids make up the water-conducting, supportive tubes in xylem.

yeast

A single-celled fungus that inhabits liquid or moist habitats and reproduces asexually by simple cell division or by the pinching of small buds off a parent cell.

vascular bundle (vas "-kyli-ler)

A strand of vascular tissues (both xylem and phloem) in a plant stem.

ultrasound imaging

A technique for examining a fetus in the uterus. High-frequency sound waves echoing off the fetus are used to produce an image of the fetus.

yellow bone marrow

A tissue found within the central cavities of long bones, consisting mostly of stored fat.

vascular tissue system

A transport system formed by xylem and phloem throughout the plant. Xylem transports water and miner-als, while phloem transports sugars and other organic nutrients.

venule (ven`-yell)

A vessel that conveys blood between a capillary bed and a vein.

vasectomy (vuh-sek`etith-me)

Surgical removal of a section of the two sperm ducts (vasa deferentia) to prevent sperm from reaching the urethra; a means of sterilization in males.

fadh2

2

kreb cycle

how much atp

X chromosome inactivation

In female mammals, the inactivation of one X chromosome in each somatic cell.

vector

In molecular biology, a piece of DNA, usually a plasmid or a viral genome, that is used to move genes from one cell to another.

uterus (Ira '-ter-us)

In the reproductive system of a mammalian female, the organ where the development of young occurs; the womb.

zygomycete (zi -guh-mi-set)

Member of a group of fungi charac-terized by a sturdy structure called a zygosporangiurn, in which meiosis produces haploid spores.

tunicate

One of a group of invertebrate chordates, also known as sea squirts.

vertebra (ver '-tuh-bruh.) (plural, vertebrae)

One of a series of seg-mented skeletal units that enclose the nerve cord, making up the backbone of a vertebrate animal.

Unikonta

One of four monophyletic supergroups proposed in a current hypothesis of the evolutionary history of eukaryotes. The other three supergroups are SAR (Stramenopila, Alveolata, and Rhizaria), Excavata, and Archaeplastida.

visceral mass (vis'-uh-rul)

One of the three main parts of a mollusc, containing most of the internal organs.

vagina (vuh-ji `-nuh)

Part of the female reproductive system between the uterus and the outside opening; the birth canal in mammals; also accommodates the male's penis and receives sperm during copulation.

ventral

Pertaining to the underside, or bottom, of a bilaterally sym-metric animal.

vascular tissue

Plant tissue consisting of cells joined into tubes that transport water and nutrients throughout the plant body.

white matter

Regions within the central nervous system composed mainly of axons, with their whitish myelin sheaths.

visual acuity

The ability of the eyes to distinguish fine detail. Nor-mal visual acuity in humans is usually reported as "20/20 vision."

vascular cylinder

The central cylinder of vascular tissue in a plant root.

vulva

The collective term for the external female genitalia.

zygote (zi '-got)

The diploid fertilized egg, which results from the union of a sperm cell nucleus and an egg cell nucleus.

wavelength

The distance between crests of adjacent waves, such as those of the electromagnetic spectrum. westerlies Winds that blow from west to east.

ventilation

The flow of air or water over a respiratory surface.

villus (vii'-us) (plural, villi)

(1) A finger-like projection of the inner surface of the small intestine. (2) A finger-like projection of the chorion of the mammalian placenta. Large numbers of Atli in-crease the surface areas of these organs.

tundra

A biome at the northernmost limits of plant growth and at high altitudes, characterized by dwarf woody shrubs, grasses, mosses, and lichens.

vertebrate (ver'-tuh-brat)

A chordate animal with a backbone, in-cluding lampreys, chondrichthyans, ray-finned fishes, lobe-finned fishes, amphibians, reptiles (including birds), and mammals.

wood ray

A column of parenchyma cells that radiates from the cen-ter of a log and transports water to its outer living tissues.

vaccine (vak-sen')

A harmless variant or derivative of a pathogen used to stimulate a host organism's immune system to mount a long-term adaptive response against the pathogen.

uracil (U) (ya ' -ruh-sil)

A single-ring nitrogenous base found in RNA.

urea (ya-re '-ah)

A soluble form of nitrogenous waste excreted by mammals and most adult amphibians.

wetland

An ecosystem intermediate between an aquatic ecosystem and a terrestrial ecosystem, where soil is saturated with water per-manently or periodically.

zoned reserve

An extensive region of land that includes one or more areas that are undisturbed by humans. The undisturbed areas are surrounded by lands that have been altered by human activity.

yolk sac

An extraembryonic membrane that develops from the en-doderm. The yolk sac produces the embryo's first blood cells and germ cells and gives rise to the allantois.

uric acid (ya '-rik)

An insoluble precipitate of nitrogenous waste ex-creted by land snails, insects, birds, and some reptiles.

vitamin

An organic nutrient that an organism requires in small quan-tities. Many vitamins serve as coenzymes or parts of coenzymes.

zooplankton (z-O-plank ' -tun)

Animals that drift in aquatic environments.

vertebral column

Backbone, composed of a series of segmented units called vertebrae.

vital capacity

The maximum volume of air that a mammal can in-hale and exhale with each breath.

urinary system

The organ system that forms and excretes urine while regulating the amount of water and ions in the body fluids.

urine

Concentrated filtrate produced by the kidneys and excreted by the bladder.

vascular cambium (vas '-kya-ler kam '-be-urn)

During secondary growth of a plant, the cylinder of meristematic cells, surrounding the xylem and pith, that produces secondary xylem and phloem.

ultimate question

In animal behavior, a question that addresses the evolutionary basis for behavior.

ultimate cause

In animal behavior, the evolutionary reason for a behavior.

water vascular system

In echinoderms, a radially arranged system of water-filled canals that branch into extensions called tube feet. The system provides movement and circulates water, facilitating gas exchange and waste disposal.

vas deferens (vas clef"-er-enz) (plural, vasa deferentia)

Part of the male reproductive system that conveys sperm away from the testis; the sperm duct; in humans, the tube that conveys sperm between the epididymis and the common duct that leads to the urethra.

xylem (zi'-lum)

The nonliving portion of a plant's vascular system that provides support and conveys xylem sap from the roots to the rest of the plant. Xylem is made up of vessel elements and/or tracheids, water-conducting cells. Primary xylem is derived from the procambium. Secondary xylem is derived from the vascular cambium in plants exhibiting secondary growth.

urinary bladder

The pouch where urine is stored prior to elimination.

wild-type trait

The version of a character that most commonly oc-curs in nature. wood Secondary xylem of a plant. See also heartwood; sapwood.