Absorption spectrum
The range of a pigment's ability to absorb various wavelengths of light.
Abyssal zone
The portion of the ocean floor where light does not penetrate and where temperatures are
cold and pressures intense.
Acanthocephala
The spiny-headed worms, a phylum of helminths; adults are parasitic in the alimentary canal
of vertebrates.
Accessory cells
Any nonlymphocytic cell that helps in the induction of the immune response by presenting
antigen to a helper T lymphocyte.
Acoelomates
An animal that lacks a coelom. Acoelomates, which include the flatworm, fluke, tapeworm,
and ribbon worm, exhibit bilateral symmetry and possess one internal space, the digestive
cavity.
Acclimatization
Physiological adjustment to a change in an environmental factor.
accommodation
The automatic adjustment of an eye to focus on near objects.
Acellular
Containg no cells; not made of cells.
Accessory Cell
A cell which is associated with the guard cell of a stoma
Acetylcholine
One of the most common neurotransmitters; functions by binding to receptors and altering
the permeability of the postsynaptic membrane to specific ions, either depolarizing or
hyperpolarizing the membrane.
Acetyl CoA
The entry compound for the Krebs cycle in cellular respiration; formed from a fragment of
pyruvate attached to a coenzyme.
Achlamydeous
Not having a floral envelope or perianth.
ff
(ff)
#1