AP Bio Chapter 47 Key Terms Flashcards
(59 cards)
acrosomal reaction
The discharge of a sperm’s acrosome when the sperm approaches an egg.
acrosome
A vesicle at the tip of a sperm cell that helps the sperm penetrate the egg.
allantois
One of four extraembryonic membranes; serves as a repository for the embryo’s nitrogenous waste.
amnion
The innermost of four extraembryonic membranes; encloses a fluid-filled sac in which the embryo is suspended.
amniote
Member of a clade of tetrapods that have an amniotic egg containing specialized membranes that protect the embryo, including mammals and birds and other reptiles.
animal pole
The portion of the egg where the least yolk is concentrated; opposite of vegetal pole.
apical ectodermal ridge
A limb-bud organizer region consisting of a thickened area of ectoderm at the tip of a limb bud.
archenteron
The endoderm-lined cavity, formed during the gastrulation process, that develops into the digestive tract of an animal.
blastocoel
The fluid-filled cavity that forms in the center of the blastula embryo.
blastocyst
An embryonic stage in mammals; a hollow ball of cells produced one week after fertilization in humans.
blastoderm
An embryonic cap of dividing cells resting on a large undivided yolk.
blastomere
A small cell of an early embryo.
blastopore
The opening of the archenteron in the gastrula that develops into the mouth in protostomes and the anus in deuterostomes.
blastula
The hollow ball of cells marking the end stage of cleavage during early embryonic development.
cadherins
An important class of cell-to-cell adhesion molecules.
cell adhesion molecules (CAMs)
Glycoproteins that contribute to cell migration and stable tissue structure.
cell differentiation
The structural and functional divergence of cells as they become specialized during a multicellular organism’s development; dependent on the control of gene expression.
chorion
The outermost of four extraembryonic membranes; contributes to the formation of the mammalian placenta.
cleavage
The process of cytokinesis in animal cells, characterized by pinching of the plasma membrane; specifically, the succession of rapid cell divisions without growth during early embryonic development that converts the zygote into a ball of cells.
convergent extension
A mechanism of cell crawling in which the cells of a tissue layer rearrange themselves in such a way that the sheet of cells becomes narrower while it becomes longer.
cortical granules
Vesicles located just under the plasma membrane of an egg cell that undergo exocytosis during the cortical reaction.
cortical reaction
Exocytosis of enzymes from cortical granules in the egg cytoplasm during fertilization.
cytoplasmic determinants
The maternal substances in the egg that influence the course of early development by regulating the expression of genes that affect the developmental fate of cells.
dorsal lip
The dorsal side of the blastopore.