Buffer
A substance that consists of acid and base forms in solution and that minimizes changes in
pH when extraneous acids or bases are added to the solution.
Bulb
A modified bud with thickened leaves adapted for underground food storage.
Bulbils
A small bulb or buld-shaped growth arising from the leaf axil or in the place of flowers.
Bulbourethral gland
One of a pair of glands near the base of the penis in the human male that secrete fluid that
lubricates and neutralizes acids in the urethra during sexual arousal.
Bulk flow
The movement of water due to a difference in pressure between two locations.
Bundle cap
A bundle cap is a a cluster of fibers that covers the top of the top or the phloem side of the
vascular bundle.
Bulliform cells
One of the large, highly vacuolated cells occurring in the epidermis of grass leaves. Also
known as motor cell.
Bundle of His
In the vertebrate heart, a group of muscle fibers that carry impulses from the
atrioventricular node to the walls of the ventricles; the only electrical bridge between the
atria and the ventricles.
C
C 3 pathway
A metabolic pathway where CO 2 is converted to 3-phosphogylycerate, the first stable intermediate
organic compound containing three carbon atoms
C 3 plant
A plant that uses the Calvin cycle for the initial steps that incorporate CO 2 into organic
material, forming a three-carbon compound as the first stable intermediate.