Bio test 4 ch 47

emmajohnson's version from 2015-04-28 01:57

Section 1

Question Answer
model organismsA particular species chosen for research into broad biological principles because it is representative of a larger group and usually easy to grow in a lab.
fertilization(1) The union of haploid gametes to produce a diploid zygote. (2) The addition of mineral nutrients to the soil.
acrosomal reactionThe discharge of hydrolytic enzymes from the acrosome, a vesicle in the tip of a sperm, when the sperm approaches or contacts an egg.
acrosomeA vesicle in the tip of a sperm containing hydrolytic enzymes and other proteins that help the sperm reach the egg.
fast block to polyspermyThe depolarization of the egg plasma membrane that begins within 1–3 seconds after a sperm binds to an egg membrane protein. The depolarization lasts about 1 minute and prevents additional sperm from fusing with the egg during that time.
slow block to polyspermyThe formation of the fertilization envelope and other changes in an egg’s surface that prevent fusion of the egg with more than one sperm. The slow block begins about 1 minute after fertilization.
zona pellucidaThe extracellular matrix surrounding a mammalian egg.
cleavage(1) The process of cytokinesis in animal cells, characterized by pinching of the plasma membrane. (2) The succession of rapid cell divisions without significant growth during early embryonic development that converts the zygote to a ball of cells.
blastomereAn early embryonic cell arising during the cleavage stage of an early embryo.
blastulaA hollow ball of cells that marks the end of the cleavage stage during early embryonic development in animals.
blastocoelThe fluid-filled cavity that forms in the center of a blastula.
yolkNutrients stored in an egg.
vegetal poleThe point at the end of an egg in the hemisphere where most yolk is concentrated; opposite of animal pole.
animal poleThe point at the end of an egg in the hemisphere where the least yolk is concentrated; opposite of vegetal pole.
holoblasticReferring to a type of cleavage in which there is complete division of the egg; occurs in eggs that have little yolk (such as those of the sea urchin) or a moderate amount of yolk (such as those of the frog).
meroblasticReferring to a type of cleavage in which there is incomplete division of a yolk-rich egg, characteristic of avian development.

Section 2

Question Answer
morphogenesisThe cellular and tissue-based processes by which an animal body takes shape.
gastrulationIn animal development, a series of cell and tissue movements in which the blastula-stage embryo folds inward, producing a three-layered embryo, the gastrula.
organogenesisThe process in which organ rudiments develop from the three germ layers after gastrulation.
gastrulaAn embryonic stage in animal development encompassing the formation of three layers: ectoderm, mesoderm, and endoderm.
germ layerOne of the three main layers in a gastrula that will form the various tissues and organs of an animal body.
ectodermThe outermost of the three primary germ layers in animal embryos; gives rise to the outer covering and, in some phyla, the nervous system, inner ear, and lens of the eye.
endodermThe innermost of the three primary germ layers in animal embryos; lines the archenteron and gives rise to the liver, pancreas, lungs, and the lining of the digestive tract in species that have these structures.
mesodermThe middle primary germ layer in a triploblastic animal embryo; develops into the notochord, the lining of the coelom, muscles, skeleton, gonads, kidneys, and most of the circulatory system in species that have these structures.
archenteronThe endoderm-lined cavity, formed during gastrulation, that develops into the digestive tract of an animal.
blastoporeIn a gastrula, the opening of the archenteron that typically develops into the anus in deuterostomes and the mouth in protostomes.
dorsal lipThe region above the blastopore on the dorsal side of the amphibian embryo.
primitive streakA thickening along the future anterior-posterior axis on the surface of an early avian or mammalian embryo, caused by a piling up of cells as they congregate at the midline before moving into the embryo.
blastocystThe blastula stage of mammalian embryonic development, consisting of an inner cell mass, a cavity, and an outer layer, the trophoblast. In humans, the __________ forms 1 week after fertilization.
inner cell massAn inner cluster of cells at one end of a mammalian blastocyst that subsequently develops into the embryo proper and some of the extraembryonic membranes.
trophoblastThe outer epithelium of a mammalian blastocyst. It forms the fetal part of the placenta, supporting embryonic development but not forming part of the embryo proper.
extraembryonic membraneOne of four membranes (yolk sac, amnion, chorion, and allantois) located outside the embryo that support the developing embryo in reptiles and mammals.
amniote Member of the clad of tetrapods named for a key derived character, the amniotic egg, which contains specialized membranes, including the fluid-filled amnion, that protect the embryo. Amniotes include mammals as well as birds and other reptiles.
notochordA longitudinal, flexible rod made of tightly packed mesodermal cells that runs along the anterior-posterior axis of a chordate in the dorsal part of the body.
neural tubeA tube of infolded ectodermal cells that runs along the anterior-posterior axis of a vertebrate, just dorsal to the notochord. It will give rise to the central nervous system.
neural crestIn vertebrates, a region located along the sides of the neural tube where it pinches off from the ectoderm. ______ _____ cells migrate to various parts of the embryo and form pigment cells in the skin and parts of the skull, teeth, adrenal glands, and peripheral nervous system.
somiteOne of a series of blocks of mesoderm that exist in pairs just lateral to the notochord in a vertebrate embryo.
convergent extensionA process in which the cells of a tissue layer rearrange themselves in such a way that the sheet of cells becomes narrower (converges) and longer (extends).
apoptosisA type of programed cell death, which is brought about by activation of enzymes that break down many chemical components in the cell.

Section 3

Question Answer
determinationThe progressive restriction of developmental potential in which the possible fate of each cell becomes more limited as an embryo develops. At the end of _____________, a cell is committed to its fate.
differentiationThe process by which a cell or group of cells become specialized in structure and function.
fate mapA territorial diagram of embryonic development that displays the future derivatives of individual cells and tissues.
totipotentDescribing a cell that can give rise to all parts of the embryo and adult, as well as extraembryonic membranes in species that have them.
pattern formationThe development of a multi-cellular organism’s spatial organization, the arrangement of organs and tissues in their characteristic places in three-dimensional space.
positional informationMolecular cues that control pattern formation in an animal or plant embryonic structure by indicating a cell’s location relative to the organism’s body axes. These cues elicit a response by genes that regulate development.
apical ectodermal ridge (AER)A thickened area of ectoderm at the tip of a limb bud that promotes outgrowth of the limb bud.
zone of polarizing activity (ZPA)A block of mesoderm located just under the ectoderm where the posterior side of a limb bud is attached to the body; required for proper pattern formation along the anterior-posterior axis of the limb.