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32 terms

AP Bio Chapter 47

Chapter 47 - animal development
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zygote
fertilized egg
preformation
the idea that the egg or sperm contains an embryo - a preformed miniture infant, or "homunculus"
epigenesis
the form of an animal emerges gradually from a relatively formless egg
cytoplasmic determinants
the material substances in the egg that influence the course of early development by regulating the expression of genes that affect the developmental fate of cells
cell differentiation
the specialization of cells in their structure and function; dependent on the control of gene expression
morphogenesis
the process by which an animal takes shape and the differentiated cells end up in the appropriate locations
three successive stages that begin to build the animal's body
cleavage, gastrulation, organogenesis
cleavage
a hollow ball of cells- blastula- is created by rapid cell division; the embryo does not enlarge during this period of development.
gastrulation
three-layer embryo - gastrula
organogenesis
rudimentary organs from which adult structures grow
fertilization
union of gamates (egg and sperm)
acrosomal reaction
the discharge of a sperm's acrosome when the sperm approaches the egg
acrosome
a vesicle at the tip of a sperm cell that helps the sperm penetrate the egg
cortical reaction
exocytosis of enzymes from cortical granules in the egg cytoplasm during fertilization
slow block to polyspermy
the formation of the fertilization envelope and other changes in the egg's surface that prevent fusion of the egg with more than one sperm
fast block to polyspermy
the depolarization of the egg membrane within 1-3 seconds after sperm binding to the vitelline layer; prevents additional sperm from fusing with the egg's plasm membrane
cortical granules
vesicles located just under the plasm membrane of an egg cell that undergo exocytosis during the cortical reaction
fertilization envelope
transformation of the viteline layer
zona pellucida
extrcellular matrix of the egg
blastomeres
small cells of the early embryo
blastoceol
the fluid-filled cavity that forms in the center of the blastula embryo
blastula
the hollow ball of cells marking the end stage of cleavage during early embryonic development
blastoderm
an embryonic cap of dividing cells resting on a large undivided yolk
archenteron
the endoderm-lines cavity, formed during the gstrulation process, that develops into the digestive tract of an animal
blastopore
the opening of thr archenteron in the gastrula that develops into the mouth in protostomes and the anus in deuterostomes
blastocyst
an embryoninc stage in mammals; a hollow ball of cellspreduced one week after fertilization in humans
chorion
a thin, pigmented inner layer of the vertebrate eye
amnion
the innermost of four extraembryonic membranes; encloses a fluiod-filled sac in which the embryo is suspended
allantois
one of four extraembryonic membranes; serves as a repository for embryo's nitrogenous waste
convergent extension
a mechanism of cell crawling in which cells of a tissue layer rearrange themselves in such a way that the sheet of cells becomes narrower while it becomes longer
cell adhesion molecules (CAMs)
glyoproteins that contribute to cell migration and stable tissue structure
apical ectodermal ridge
a limb-bud organizer region consisting of a thickened area of ectoderm at the tip of a limb bud