words of biology, pronounciation and definition
1편 입니다. (( 밑에 계속 연재 합니다. )) - 무한 수정중입니다.
abiotic components The nonliving players in an ecosystem,
such as climate and nutrients.
abscisic acid Plant hormone that inhibits cell growth,
prevents premature germination, and stimulates closing of the stomata.
achondroplasia Autosomal dominant form of dwarfism
seen in one out of 10, 000 people.
ACTH See adrenocorticotropic hormone.
active site Part of the enzyme that interacts with the
substrate in an enzyme–substrate complex.
active transport The movement of a particle across
a selectively permeable membrane against its concentration gradient. This movement requires the
input of energy, which is why it is termed “active” transport.
adaptation A trait that, if altered, affects the fitness of the organism. Adaptations are the result of natural
selection and can include not only physical traits such as eyes and fingernails but also the intangible
traits of organisms, such as lifespan.
adaptive radiation A rapid series of speciation events
that occur when one or more ancestral species invades a new environment.
ADH See antidiuretic hormone.
adrenocorticotropic hormone (ACTH) A hormone
that stimulates the secretion of adrenal cortical hormones, which work to maintain electrolytic
homeostasis in the body.
aerobic respiration Energy-producing reactions in animals that involve three stages: glycolysis, the
Krebs cycle, and oxidative phosphorylation. Requires oxygen.
age structure Statistic that compares the relative
number of individuals in the population from each age group.
agonistic behavior Behavior that results from a conflict
of interest between individuals; often involves intimidation and submission.
alcohol Organic compound that contains a hydroxyl
(—OH) functional group.
alcohol fermentation Occurs in fungi, yeast, and
bacteria. Pyruvate is converted in two steps to
ethanol, regenerating two molecules of NAD+.
aldehyde Carbonyl group in which one R is a hydrogen
and the other is a carbon chain. Hydrophilic and polar.
aldosterone Released from the adrenal gland, this
hormone acts on the distal tubules to cause the
reabsorption of more Na+ and water. This increases blood volume and pressure.
allantois Transports waste products in mammals
to the placenta. Later it is incorporated into the umbilical cord.
allele A variant of a gene for a particular character.
allopatric speciation Interbreeding ceases because
some sort of barrier separates a single population into two (an area with no food, a mountain, etc.).
The two populations evolve independently, and if they change enough, then, even if the barrier is
removed, they cannot interbreed.
alternation of generations Plant life cycle, so named
because during the cycle, plants sometimes exist as
a diploid organism and at other times as a haploid organism.
altruistic behavior Behavior pattern that reduces the
overall fitness of one organism while increasing the fitness of another.
alveoli Functional unit of the lung where gas exchange occurs.
amines Compounds containing amino groups.
amino acid A compound with a carbon center surrounded
by an amino group, a carboxyl group, a hydrogen, and an R group that provides an amino
acid’s unique chemical characteristics.
aminoacyl tRNA synthetase Enzyme that makes sure
that each tRNA molecule picks up the appropriate amino acid for its anticodon.
amino group A functional group that contains
—NH2 and that acts as a base; an example is an amino acid.
amnion Structure formed from epiblast that encloses
the fluid-filled cavity that helps cushion the developing embryo.
amygdala The portion of the human brain that
controls impulsive emotions and anger.
2편 입니다. (( 밑에 계속 연재 합니다. ))
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 delivering oxygen.
aneuploidy The condition of having an abnormal
number of chromosomes.
angiosperm Flowering 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.
antheridia Male 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 pathway Movement of water and nutrients through the nonliving portion of cells.
aposematic coloration Warning coloration adopted
by animals that possess a chemical defense mechanism.
archaebacteria One of two major prokaryotic evolutionary
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 learning Process 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 hydrogens
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 chromosome One that is not directly involved in determining gender.
autotroph An organism that is self-nourishing.
It obtains carbon and energy without ingesting other organisms.
auxin Plant 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 bodies Inactivated 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 interaction
between animals and their environments from an evolutionary perspective.