5 Steps to a 5 AP Biology, 2014-2015 Edition

(Marvins-Underground-K-12) #1

316 ❯ Glossary


amylase Enzyme that breaks down the starches in the
human diet to simpler sugars such as maltose, which
are fully digested farther down in the intestines.
anaerobic respiration Energy-producing reactions,
known as fermentation,that do not involve oxygen.
It begins with glycolysis and concludes with the
formation of NAD+.
anemia Illness in which a lack of iron causes red
blood cells to have a diminished capacity for deliv-
ering oxygen.
aneuploidy The condition of having an abnormal
number of chromosomes.
angiospermFlowering plant divided into monocots
and dicots (monocotyledons and dicotyledons).
anion Ion with a negative charge that contains more
electrons than protons.
anterior pituitary gland Structure that produces six
hormones: TSH, STH (or HGH), ACTH, LH,
FSH, and prolactin.
anther Pollen-producing portion of a plant.
antheridiaMale gametangia in bryophytes and ferns
designed to produce flagellated sperm that swim to
meet up with the eggs produced by the female
gametangia.
anticodon Region present at a tRNA attachment
site; a three-nucleotide sequence that is perfectly
complementary to a particular codon.
antidiuretic hormone (ADH) A hormone produced
in the brain and stored in the pituitary gland; it
increases the permeability of the collecting duct to
water, leading to more concentrated urine content.
antigen A molecule that is foreign to our bodies and
causes our immune systems to respond.
apical meristem Region at the tips of roots and
shoots where plant growth is concentrated and
many actively dividing cells can be found.
apoplast pathwayMovement of water and nutri-
ents through the nonliving portion of cells.
aposematic colorationWarning coloration adopted
by animals that possess a chemical defense
mechanism.
archaebacteria One of two major prokaryotic evo-
lutionary branches. These organisms tend to live
in extreme environments and include halophiles,
methanogens, and thermoacidophiles.
archegonium Female gametangia in bryophytes,
ferns, and gymnosperms.
archezoa Eukaryotic organism that allegedly most
closely resembles prokaryotes.


arteries Structures that carry blood away from the
heart.
artificial selection When humans become the agents
of natural selection (breeding of dogs).
ascospores Haploid meiotic products produced by
certain fungi.
A site Region on protein synthesis machinery that
holds the tRNA carrying the next amino acid.
associative learningProcess by which animals take
one stimulus and associate it with another.
atom The smallest form of an element that still
displays its unique properties.
ATP synthase Enzyme that uses the flow of hydro-
gens to drive the phosphorylation of an adenosine
diphosphate molecule to produce adenosine
triphosphate.
auditory communication Communication that
involves the use of sound in the conveying of a
message.
autonomic nervous system (ANS) A subdivision of
the peripheral nervous system (PNS) that controls
the involuntary activities of the body: smooth
muscle, cardiac muscle, and glands. The ANS is
divided into the sympathetic and parasympathetic
divisions.
autosomal chromosomeOne that is not directly
involved in determining gender.
autotroph An organism that is self-nourishing.
It obtains carbon and energy without ingesting
other organisms.
auxinPlant hormone that leads to elongation of
stems and plays a role in phototropism and
gravitropism.
axon A longer extension that leaves a neuron and
carries the impulse away from the cell body toward
target cells.
balanced polymorphism When there are two or more
phenotypic variants maintained in a population.
bare-rock succession The attachment of lichen to
rocks, followed by the step-by-step arrival of
replacement species.
Barr bodiesInactivated genes on X chromosomes.
Batesian mimicry An animal that is harmless copies
the appearance of an animal that is dangerous as a
defense mechanism to make predators think twice
about attacking.
behavioral ecology Science that studies the interac-
tion between animals and their environments from
an evolutionary perspective.
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