A Flashcards
Absorption
The movement of digested food molecules through the wall of the intestine into the blood or lymph
Accommodation
The adjustment of the shape of the lens so as to focus light onto the retina
Acid Rain
Rain or snow which is acidic. Polluting gases such as sulfur dioxide and the oxides of nitrogen react with water in the atmosphere to form acid rain
Active Immunity
The body produces its own antibodies in response to an antigen, either on the surface of a pathogen or in a vaccine
Active Site
Part of the surface of an enzyme molecule into which the substrate fits
Active Transport
The movement of molecules or ions in or out of a cell through the cell membrane from a region of their lower concentration to a region of their higher concentration against a concentration gradient, using energy released from respiration
Adaptation
A feature that helps an organism to survive in its environment
Adaptive Feature
an inherited feature that increases an organism’s fitness.
Addiction
When a person has taken a drug so regularly that they cannot do without it
Adrenaline
A hormone produced by the adrenal glands that prepares the body for emergencies and stress, for example by increasing the glucose concentration of the blood.
Aerobic Respiration
The process that happens in cells to release a relatively large amount of energy from food substances, such as glucose, in the presence of oxygen.
AIDS
Acquired immunodeficiency syndrome - a collection of diseases that result from a weakening of the body’s immune system following infection by HIV
Allele
Any of two or more alternative forms of a gene.
Alveolus
A tiny air sac in the lungs where exchange of gases between the air and blood occurs
Amino Acid
A molecule made up of carbon, hydrogen, oxygen and nitrogen. Amino acids link together by chemical bonds to form protein molecules. Some amino acids also contain sulfur.
