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39 Cards in this Set
- Front
- Back
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The Sperm consists of what three things?
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haploid nucleus, a propulsion system, and a sac of enzymes
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Is sperms cytoplasm eliminated or does it remain during maturation? egg?
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eliminated; maintained
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What is the area anterior to the haploid nucleus that contains enzymes to digest proteins and sugars?
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acrosome
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What lies between the nucleus and the acrosome? What do they do?
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actin molecules; help extend an acrosomal process
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What is the axoneme?
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The motor portion of the flagellum that contains 2 central microtubules surrounded by a row of 9 doublet microtubules.
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What protein is attached to the flagella? What does it do?
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dynein; hydrolyses ATP and converts the chemical energy into mechanical energy
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What does the plasma membrane do in the egg?
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regulates flow of certain ions during feriliazation and fuses with sperm plasma membrane
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What lies outside the plasma membrane of the egg? Outside of that layer?
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Vitelline membrane; egg jelly
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What is used to attract sperm?
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egg jelly
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What is on the inner layer of the plasma membrane of the egg?
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corex and cortrical granules
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What is homologous to acrosomal vesicles in sperm?
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cortical granules
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What do the cortical granules do?
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Prevent other sperm from entering the egg after the first sperm enters.
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Polyspermy results in what?
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abnormal, arrested development
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Sperm find the egg via what method?
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chemotaxis
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What peptide is in the egg jelly that attracts the sperm?
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resact
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What is the second molecule used in identification of species?
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Bindin; interacts with membranes on the egg
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What is formed at the point of sperm entry?
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fertilization cone
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What two ways is polyspermy prevented?
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1. electrical potential of the plasma membrane changes after sperm binding
2. cortical granules in the egg release their contents into the spce b/w the pla mem. and vitelline memb.(they remove bindin receptors and any attached sperm) |
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When water enters the space between the plasma membrane and the vitellin membrane, what is created?
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Fertilization membrane
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What type of cleavage do sea urchins undergo?
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Radial holoblast cleavage
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During division, the top half creates ___ nad the bottom half creates __.
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8 mesomeres; 4 macromeres and 4 micromeres
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The 8 mesomeres create ___ and ___.
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two animal tiers (an1 and an2)
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At the 128 cell stage, the embryo is a ___.
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Blastula with a blastocoel inside (1 cell thick and no zygotic gene expression yet)
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Zygotic genes are first expressed when?
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MBT (10th division)
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What do the cells at the vegetal pole do? Animal pole?
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Form vegetal plate; secrete enzyme to digest fertilization membrane so its now free swimming blastula.
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When does gastrulation begin?
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After blastula is free swimming
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What happens in the beginning of gastrulation?
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Primary mesenchyme ingresses from the vegetal plate into the blastocoel
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Primary mesenchyme eventually forms the
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axis of calcium carbonate spicules
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The blastopore eventually becomes the ___.
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anus
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What is injected to see what the gametes look like?
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KCl into coelem
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In the zebrafish mutant MIB, what is deformed?
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DN pathways; used to make somites, floor plate dev, and hindbrain patterning (otic)
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In the zebrafish mutant SPT, what is deformed?
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a VegT homologue (bra hom too) so cells in the lateral marginal zone dont migrate right. No trunk somites
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In zebrafish, ACE creates what deformity?
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FGF8 mutant; loss of mid-hind border, cerebellum, small ears; fgf8 maintains pax genes
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In zebrafish, ntl creates what deformity?
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It is a brachyury homologue; no notochord, these cells are scattered along midline. Somites ARE created!
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In zebrafish, oep creates what deforminty?
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It is a mutation in a cofactor for nodal signaling. lack endoderm, no prechordal plate, only one eye
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The teratogen LiCl does what? What pathway does it affect? What is deformed in zebrafish?
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affects mesoderm vegatlization in Xenopus, turns heads into feet in Hydra, hurts AV axis in sea urchin; Wnt (B-cat); no eyes and reduced forebrain
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The teratogen RA does what? In zebrafish?
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causes expression of Hox genes in cells that shouldn't express them. (AP axis); deformed tails and u cant see eyes because mostly hindbrain tissue
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What does the teratogen Sodium Chlorate do? In zebrafish?
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Inhibits sulfation by inhibiting ATP sulfurylase so FGF can't bind to its receptor; no tail or trunk
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How can cells in the presence of sodium chlorate be rescued?
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MgSO4 (allows sulfation to occur)
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