Science / Biology Glossary

Bryophytes: The nonvascular plants, characterized by life cycles dominated by the gametophyte phase. This group includes the mosses, liverworts, and hornworts, which lack lignified conducting tissues.

Bud Sports: Buds that produce fruit that is different from the rest of the fruit on the tree; vegetatively propagated by grafting cuttings onto another plant.

Budding: 1. Asexual production of new organisms; usually found in yeast; 2. the process by which HIV and similar viruses leave the cell (other than by lysing).

Buffers: Chemicals that maintain pH values within narrow limits by absorbing or releasing hydrogen ions.

Bulbourethral Glands: Glands that secrete a mucus-like substance that is added to sperm and provides lubrication during intercourse.

Bursae: Small sacs lined with synovial membrane and filled with synovial fluid; act as cushions to reduce friction between tendons and bones.

Calcitonin: A hormone produced by the thyroid that plays a role in regulating calcium levels.

Calcium Carbonate: Chemical that also occurs in limestone and marble.

Calvin Cycle: Series of biochemical, enzyme-mediated reactions during which atmospheric carbon dioxide is reduced and incorporated into organic molecules, eventually some of this forms sugars. In eukaryot . . . View Full Definition

Cambium: A lateral meristem in plants. Types of cambiums include vascular, cork, and intercalary.

Cambrian: Geologic period that begins the Paleozoic Era 570 million years ago. Marked in its beginning by a proliferation of animals with hard, preservable parts, such as brachiopods, trilobites, and . . . View Full Definition

Campodactyly: A dominant trait in which a muscle is improperly attached to bones in the little finger, causing the finger to be permanently bent.

Capillaries: Small, thin-walled blood vessels that allow oxygen to diffuse from the blood into the cells and carbon dioxide to diffuse from the cells into the blood.

Capillary Bed: A branching network of capillaries supplied by arterioles and drained by venules.

Capsid: The protein shell of a free virus particle. This definition is from the Glossary at the UCMP site at http://www.ucmp.berkeley.edu/glossary/gloss4cell.html

Capsule: 1. Structure produced around certain bacteria; 2. Structure produced by the bryophyte sporophyte that contains spores produced by meiosis.

Carbohydrates: Organic molecules composed of carbon, hydrogen, and oxygen that serve as energy sources and structural materials for cells of all organisms.

Cardiac Cycle: One heartbeat; consists of atrial contraction and relaxation, ventricular contraction and relaxation, and a short pause.

Cardiac Muscle: The type of muscle that is found in the walls of the heart. Cardiac muscle is striated but branched, unlike the straight-shaped striated skeletal muscle cells.

Cardiovascular System: The human circulatory system consisting of the heart and the vessels that transport blood to and from the heart.

Carnivores: Term applied to a heterotroph, usually an animal, that eats other animals. Carnivores function as secondary, tertiary, or top consumers in food chains and food webs.

Carotenoids: Major group of accessory pigments in plants; includes beta carotene.

Carpals: The bones that make up the wrist joint.

Carpels: The female reproductive structures of a flower; consisting of the ovary, style, and stigma.

Carrageenan: Chemical extracted from red algae that is added to commercial ice creams as an emulsifying agent.

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