U–Z
U
- uterus
- Structure
in the female reproductive system in which the embryo develops.
V
- vascular cambium
- Tissue
that produces new vascular cells; lies between the xylem and phloem in
dicot stems.
- vascular tissue
- A
conductive component (either xylem or phloem) of the vascular system
that transports food and nutrients throughout the plant body.
- vegetative propagation
-
A form of asexual reproduction in which plants produce
genetically identical offshoots (clones) of themselves, which then
develop into independent plants.
- vein
- A blood
vessel that carries blood back to the heart. The blood in veins
is not oxygenated, with the exception of the pulmonary vein.
- vertebrate
- An
animal that has a skeletal rod of bone or cartilage running up its
back, surrounding the nerve cord. Segments of this rod are called
vertebrae. All vertebrate animals belong to subphylum Vertebrata,
part of phylum Chordata.
- vestigial structures
-
Bodily structures that developed in the past but no
longer serve any function for an organism.
- villi
- Fingerlike
projections in the small intestine that increase surface area and
maximize the absorption of nutrients.
- vitamins
- Complex
molecules that usually serve as coenzymes, assisting in physiological processes.
W
- warm-blooded
- Animals
that have developed fat and fur, hair, or feathers in order to retain
heat produced by metabolic activities. Also known as endothermic.
Warm-blooded animals are able to thrive in various climates, because
they are minimally affected by environmental fluctuations in temperature.
X
- xylem
- Vascular
tissue composed of cells that are dead at maturity; transports water
and dissolved minerals upward from the roots to the shoot.
Z
- zygote
- In sexual
reproduction, the diploid product of the fusion of the father’s
haploid sperm cell and the mother’s haploid ovum (egg) cell. The
single-celled zygote divides billions of times to form a whole individual.
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