BIOLOGY KEY TERMS Flashcards
abundance
a measure of how common or rare a particular type of organism is in a given environment
active site
the site on an enzyme where the reactants bind
active transport
the movement of substances from a dilute solution to a more concentrated solution against a concentration gradient, requiring energy from respiration
adaptations
special features that make an organism particularly well suited to the environment where it lives
ADH
anti-diuretic hormone helps control the water balance of the body and affects the amount of urine produced by the kidney
adrenaline
hormone that prepares the body for flight or fight
adult stem cells
stem cells that are found in adults that can differentiate and form a limited number of cells
aerobic respiration
an exothermic reaction in which glucose is broken down using oxygen to produce carbon dioxide and water and release energy for the cells
agar gel
widely used solid (gel) culture medium used for growing microorganisms
algae
simple aquatic organisms (protista) that make their own food by photosynthesis
alleles
different forms of the same gene sometimes referred to as variants
alveoli
tiny air sacs in the lungs that increase the surface area for gaseous exchange
amino acids
molecules made up of carbon, hydrogen, oxygen, and nitrogen that are the building blocks of proteins
amylase
enzyme that speeds up the digestion of starch into sugars
anaerobic respiration
an exothermic reaction in which glucose is broken down in the absence of oxygen to produce lactic acid in animals and ethanol and carbon dioxide in plants and yeast. A small amount of energy is transferred for the cells
aorta
the artery that leaves the heart from the left ventricle and carries oxygenated blood to the body
aphids
insects that penetrate the plant phloem and feed on the dissolved food. They act as vectors that carry pathogenic viruses, bacteria, and fungi into healthy plant tissue
archaea
one of the three domains, containing primitive forms of bacteria that can live in many of the extreme environments of the world.
arteries
blood vessels that carry blood away from the heart. They usually carry oxygenated blood and have a pulse
asexual reproduction
involves only one individual and the offspring is identical to the parent. There is no fusion of gametes or mixing of genetic information
atria
the upper chambers of the heart
auxin
a plant hormone that controls the responses of plants to light (phototropism) and gravity (gravitropism)
bacteria
single celled prokaryotic organisms
bases (DNA)
nitrogenous compounds that make up part of the structure of DNA and RNA. They are represented by the letters A, T, C, and G