Sea Urchin Embryology Back to Contents page







ACROSOME - [acrosoma] an organelle at the front of the sperm containing a packet of material which contains enzymes necessary for dissolving a passage through the egg jelly or zona pellucida.

ANAPHASE - [anafase] a stage of division in mitosis or meiosis during which sister chromatids separate and are pulled to opposite poles.

ANION - [anion] an ion with a negative charge.

BINARY FISSION - [fision binaria] division a prokaryotic cell into two cells by an apparently simple division of nucleus and cytoplasm.

BINDIN - [bindina] a protein on the surface of an acrosome reacted sperm that binds to the surface of an egg.

BLASTULA - [blastula] a hollow ball of cells, one layer thick, formed by cleavage in the early development of the embryo (follows the morula stage)

CADMIUM - [cadmio] a naturally occurring carcinogenic toxic heavy metal usually associated with waste motor oil (produced as a result of use in a motor containing cadmium alloyed metals)

CARCINOGENIC - [carcinogenico] can cause cancer

CATION - [cation] an ion with a positive charge.

CENTROSOME - [centrosoma] along with its associated proteins, the centrosome is THE structural organizing center of the cell. All microtubules originate at a protein on the centrosome. A folded centrosome can become a centriole or basal body for cillia and flagella.

CLASSIFICATION - [classificacion] an arrangement of life forms into groups based on some or all of their similarities and differences.

CONCENTRATION - [consentracion] the amount of a specified substance in a unit measure of another substance.

CONDENSER - [condensador] the glass lens used to focus the light beam onto the objective lens, passing through the specimen.

CONTROL - [control] the group in which all variables remain constant including the independent variable.

CORTICAL GRANULE - [granulo cortical] a large membrane bound vesicle near the surface of the egg that fuses with the plasma membrane during fertilization releasing its contents to raise and harden the fertilization membrane.

CYTOKINESIS - [citocinesis] the separation of the cytoplasm of the parent cell into two daughter cells following nuclear division.

DARKFIELD - [campo oscuro] illumination in a microscope whereby the light hits the specimen at an oblique angle as opposed to directly transmitted light. This results in the specimen being lit and the background remaining dark.

DEPENDENT VARIABLE - [variable dependiente] in an experiment, any change that results from the manipulation of the independent variable.

DETERGENT - [detergente] a molecule with hydrophobic and hydrophilic ends that disperses water insoluble compounds.

DEVELOPMENT - [desarrollo] the changes undergone by an organism from its beginning to maturity. One of the four functions that distinguish life.

DIAPHRAGM - [diafragma] the mechanical part of the microscope near the condenser lens that regulates the amount of light entering the body tube.

DILUTE, adj, - [disolvente] a low concentration
[diluir] to dilute - to decrease the concentration

DILUTION, LINEAR - [dilusion lineal] made by a single dilution from a common stock.

DILUTION, SERIAL - [dilucion en serie] to make a concentration by repeated sequence of dilutions.

DNA SYNTHESIS - [sintesis de ADN] the chemical, enzymatic act of replicating the DNA molecule.

EMBRYO - [embrion] a young organism in the early stages of development.

ENVIRONMENT - [ambiente] the sum total of external influences acting on an organism or on part of an organism.

EPA - Environmental Protection Agency, A REALLY NEAT WEB SITE!

EXTINCTION - [extincion] a condition that occurs when the number of individuals in a population falls below the level that will allow for sustainable reproduction.

FERTILIZATION - [fertilizacion o fecundacion] the union of egg and sperm to form the zygote.

FERTILIZATION CONE - [cono de fecundacion (o fertilizacion)] a protuberance on the egg at the point of contact and entry of the sperm during fertilization.

FERTILIZATION MEMBRANE - [membrana de fertilizacion (o fecundacion)] a membrane formed by an egg in response to its union with a sperm, which grows rapidly from the point of union and covers the egg, excluding other sperm.

FERTILIZATION, EXTERNAL - [fertilizacion externa] fertilization outside the body of the parents

FERTILIZATION, INTERNAL - [fertilizacion interna] fertilization inside the body of a parent

FILAMENTOUS ACTIN, F-ACTIN - [actina filamentosa] the long fiber like form of actin, a structural protein found in most cells.

FUNGICIDE - [fungicida] chemical agent capable of preventing growth of a fungus

GAMETES - [gametos] haploid cells which fuse to form a zygote in sexual reproduction, usually refers to an egg or sperm cell.

GASTRULATION - [gastrulacion] the process in which the migration of cells through the bastopore produces the primitive gut and the two layered gastrula.

GLOBULAR ACTIN, G-ACTIN - [actina globular] the spherical form of actin, a structural protein in most cells.

GONAD - [gonada] the ovaries or testes, the organ that produces gametes, eggs or sperm.

HATCHING - [eclosion] in sea urchins, when the blastula breaks free of the fertilization membrane and becomes free swimming.

HOST - [hospedero] the organism preyed upon by a parasite.

INDEPENDENT VARIABLE - [variable independiente] the only variable to be manipulated or changed in a controlled experiment.

JELLY - [capa gelatinosa or gelatina] the polysaccharide layer with associated proteins the protects the outside of an unfertilized egg from mechanical damage and too many sperm entering at once. The protein associated with the jelly is responsible for initiating the acrosome reaction in sperm of the same species.

K-SELECTION - [seleccion K] "Brooders", those animals that have few offspring, but take care of them to help insure survival.

LIGHT - [luz] the visible portion of the electromagnetic spectrum that humans are capable of detecting, ranging from roughly 400 nm to 700 nm.

MEIOSIS - [meiosis] production of haploid cells, usually eggs or sperm, through division of diploid cells, a source of genetic variation.

METAPHASE - [metafase] the stage in mitosis or meiosis when the chromosomes gather at the equator of the spindle and become aligned.

MICRO CENTRIFUGE TUBE - [tubo de microcentrifuga] small polypropylene plastic conical tube with attached cap. Size varies from 0.25ml to 2ml.

MICROTUBULES - [microtubulos] protein complex of the cytoskeleton in eukaryotes that helps certain organelles move. The mitotic spindle, cilia, and flagella contain microtubules

MITOCHONDRIA - [mitocondria] the "energy" factory of the cell. converts glucose to ATP. thought to have been evolved from a bacterial ancestor that was incorporated into the eukaryotic cell.

MITOSIS - [mitosis] the process by which chromosomes are duplicated and distributed to form daughter nuclei identical to the parent cell, followed by cytokinesis (cell division).

NUCLEAR FUSION - [fusion nuclear] the joining of the male and female pronuclei into one nucleus.

OSMOLARITY - [osmolaridad] a measure of the molecular tension or force applied across a bipolar membrane.

PARASITE - [parasito] an organism living in or on another species to gain food at the expense of the host.

PARTHENOGENESIS - [partenogenesis] activation of an egg to induce reproduction without fertilization by a male gamete.

PASTEUR PIPET - [pipeta de pasteur] a glass tube approximately 6mm in diameter pulled to a tapered tip to facilitate transport of liquids. see pipet.gif

pH - [pH] a measure related to the hydrogen ion content of a solution which represents the acidity or alkalinity of that solution.

PLASMA MEMBRANE - [membrana plasmatica] the cell membrane consisting of a bilayer of phospholipids and proteins.

PLUTEUS - [pluteus] the free swimming larva of sea urchins, sand dollars and brittle stars which resembles on upturned easel.

POLYSPERMY - [polispermia] entry of several sperm into one egg.

POTASSIUM CHLORIDE - [cloruro de potasio] as opposed to sodium chloride, used to cause muscular contraction in the body of the sea urchin, thus inducing spawning.

PREDATOR - [depredador] an animal that kills other animals for food.

RECEPTOR - [receptor] a protein on the surface of the plasma membrane that reacts to an external chemical agent, passing the "signal" to the internal side of the membrane.

r-SELECTION - [seleccion R] "Spawners", those animals that have many offspring with no care, in hopes that shear numbers will overwhelm prey.

SALINITY - [salinidad] the measure of the salt content of a solution.

SKELETON, SEA URCHIN - [esqueleto del erizo de mar] the hard framework which supports and protects the softer parts. External "test with spines attached" in the adult and internal in pluteus.

SPAWNER - ["desobadores"] an organism that reproduces by expelling eggs and sperm into the water to facilitate external fertilization.

SPECIATION - [especiacion] the processes by which new species are formed.

SPECTRUM - [espectro] the electromagnetic spectrum, of which visible light is a small part. Also includes X-rays to radio waves. Can also refer to a spectral scan, which shows the absorbance or transmittance of a chemical in respect to a specified range of wavelengths of light.

SPERM MOTILITY - [motilidad espermatica] the ability of sperm to move.

STREAK - ["raya"] when the centrosome duplicates, the spreading of the centrosome and associated microtubules results in a clearing in the cell resembling a streak.

SURVIVAL STRATERY - [estrategia de sobrevivencia] any genetic or behavior strategy that may benefit an organisms survival.

SYNGAMY - [singamia] the process whereby the male and female gametes find each other and join. synonymous with sexual reproduction.

TOXIC - [toxico] poisonous.

VANADIUM - [vanadio] a naturally occurring carcinogenic toxic heavy metal usually associated with waste motor oil (produced as a result of use in a motor containing vanadium alloyed metals)

ZONA PELLUCIDA - [zona pelucida] area around a mammalian egg used to help exclude excess sperm from fertilizing the egg.

ZYGOTE - [cigoto] the diploid cell that results from the union of gametes.