Barron's Glossary Terms Flashcards
Abiotic Factors
Nonliving factors in an ecosystem
Abscisic acid (ABA)
Plant hormone that inhibits growth
Accessory pigments
(Also Antennae) Molecules that assist in photosynthesis by capturing and passing on photons of light to chlorophyll a and expanding the range of light that can be used to produce sugar. Examples are chlorophyll b and the caretenoids.
Acoelomate
An animal that has no true coelom; ex: flatworms
Actin
Protein that makes up the thin myofilaments in skeletal muscle
Active Transport
movement of particles against a gradient, from low concentration to high concentration. This always requires the expenditure of energy
Adventitious roots
roots that rise above the ground; examples are aerial roots and prop roots
Agonistic behavior
aggressive behavior
Alcohol fermentation
The process by which certain cells convert pyruvic acid or pyruvate from glycolysis into ethyl alcohol and carbon dioxide in the absence of oxygen
Allantois
Extra embryonic membrane in a bird’s egg. Exchanges respiratory gases to and from the embryo
Alleles
Alternate forms of a gene. For example, there are two of these for height in pea plants: tall and dwarf.
Alveoli
Microscopic air sacs in the lung where diffusion of the respiratory gases, oxygen and carbon dioxide occurs
Amnion
Membrane that encloses the embryo in protective amniotic fluid
Amylase
Enzyme that digests starch
Analogous structures
Structures, such as a bat’s wing and a fly’s wing, that have the same function but not the same underlying structure (not evidence of a common origin).
Aneuploidy
any abnormal condition of the chromosomes
Angiosperms
Anthophyta or flowering plants
Anion
a negative ion
Antennae
(Also accessory pigments) Molecules that assist in photosynthesis by capturing and passing on photons of light to chlorophyll a and expanding the range of light that can be used to produce sugar. Examples are chlorophyll b and the caretenoids.
Anther
Male part of flower where sperm (pollen) is produced by meiosis. Sits atop the filament
Antheridia
structures located on the tips of a gametophyte plant and produce sperm
Antibodies
Immunoglobins. Part of the third line of defense, the specific immune response. Each molecule is a Y shaped molecule consisting of four polypeptide chains
Anticodon
The three nucleotide sequence associated with tRNA
Antigens
anything that triggers an antibody response
Apoptosis
programmed cell death
Archaeopteryx
intermediate fossil that shows both reptile and bird characteristics
Archegonia
structures located on the tips of a gametophyte plant and that produces eggs.
Associative learning
one type of learning in which one stimulus becomes linked to another through experience.
ATP
special high energy molecule that stores energy for immediate use in the cell
ATP synthase
structure in the membranes of mitochondria and chloroplasts where ATP is formed
Autonomic nervous system
part of the nervous system that controls automatic functions, such as heart and breathing rate
Autosomes
chromosomes other than the sex chromosomes. Humans have 44 in each cell
Auxins
growth hormones in plants that are responsible for phototropisms and apical dominance, the preferential growth of a plant towards the sun
Backcross
Testcross. a technique to determine whether an individual plant or animal showing the dominant trait is homozygous dominant or heterozygous
Bacterial transformation
the ability of bacteria to alter their genetic makeup by uptaking foreign DNA from another bacerial cell and incorporating it into their own. Discovered by Griffith
Base-pair substitution
a mutation where one nucleotide is substituted for a correct one in a DNA strand
Bicarbonate ion
the most important buffer in human blood. It is responsible for keeping the pH of blood at 7.4
Bile
chemical produced in the liver and released from the gallbladder that emulsifies fats. It is not an enzyme.
Binomial nomenclature
system of taxonomy that we use today, developed by Carl von Linné. In this system, every organism has a two part name, like Homo Sapiens.
Biosphere
the global ecosystem
Biotechnology
branch of science that uses recombinant DNA techniques for practical purposes, also called genetic engineering
Biotic factor
includes all the organisms with which an organism might react in an ecosystem
Biotic potential
the maximum rate at which a population could increase under ideal conditions
Bottleneck effect
natural disasters such as fire, earthquake, and flood reduce the size of a population nonselectively, resulting in a loss of genetic variation. The resulting population is much smaller and not representative of the original one. Certain alleles may be under or overrepresented compared with the original population.
Budding
splitting off of new individuals from existing ones. how reproduction occurs in hydra.
Buffers
chemicals that resist a change in pH
C-4 photosynthesis
modification for dry environments. C-4 plants exhibit modified anatomy and biochemical pathways, which enable them to minimize excessive water loss and maximize sugar production.
Calvin cycle
cyclical process that produces sugar. It occurs during the light-independent reactions.
Carbon fixation
incorporation of carbon dioxide into a sugar. Occurs during the Calvin cycle.
Cardiac sphincter
band of muscle at the top of the stomach that keeps acidified food in the stomach from backing up into the esophagus and burning it.
Carotenoids
photosynthetic antennae pigments. they are orange and yellow.
Carpel
Female part of the flower, produce the female gametophytes, ova. Each consists of an ovary, stigma and style. Also called the pistil.
Carrying Capacity (K)
a limit to the number of individuals that can occupy one area at a particular time.
Cation
a positive ion.
Centrioles
responsible for division of the cytoplasm in animal cells; they are not present in plant cells. They consist of 9 triplets of microtubules arranged in a circle.
Centromere
specialized region of a chromosome that holds two sister chromatids together
Centrosome
consist of two centrioles at right angles to each other. Important during cell division in animal cells.
Chemiosmosis
how ATP is produced during oxidative phosphorylation. Protons only flow through the special ATP synthetase channels and transfer energy to molecules of ATP.
Chitin
a polysaccharide that makes up the exoskeleton of insects and the cell walls of fungi.