Burden, Sierra, Friday G, DevBio, PreLab 2

Burden, Sierra, Friday G, DevBio, PreLab 2 - Developmental...

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Developmental Biology Pre-Lab Assignment 2: Protocol, Materials Request Form, and Presentation Protocol: 10 points Title : Polyspermy in de-jellied Strongylocentrotus purpuratus eggs at the first cleavage and blastula stage - Be sure to mention the name of the species: Strongylocentrotus purpuratus . - Say which 2 stages of development you will be studying and what variables you will introduce. Objective Statement In the article The Effect of Soluble Egg Jelly on the Fertilizability of Acid-De-Jellied Sea Urchin Eggs, a experiment was conducted to observe the consequences of adding soluble egg jelly to de-jellied eggs of two different species. Sea urchin and Lytechinus pictus eggs were de-jellied using an acid mechanism and soluble egg jelly was added to them. Lytechinus pictus experienced diminished fertilization without the soluble egg jelly, while the sea urchins had increased fertilization. The experiment used a specific egg de- jellying method, acid soaking, but in this assessment two additional techniques will be used: soaking and mechanical swirling. The amount of polyspermy in each sample will be compared in the first cleavage and blastula stage. A control sample with a jellied egg will also be used in this experiment. The control should produce eggs without any polyspermy because sperm need to penetrate the jelly coat via the acrosomal reaction. The de-jellied egg samples, however, will have similar amounts of polyspermy at both stages. The differences in the amount of polyspermy at the first cleavage and blastulation should not be significant. - Briefly summarize your reference and transition into what your experimental question is. - Include Experimental Hypothesis, with a mechanism-based explanation of the prediction Materials and Methods 1) Obtain the eggs and sperm by injecting a sea urchin with potassium chloride. Shake the sea urchin for several minutes. The potassium chloride will make the sea urchin release its gametes. 2)
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This note was uploaded on 09/19/2011 for the course BIOLOGY 44Y taught by Professor Smith during the Winter '11 term at Stanford.

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Burden, Sierra, Friday G, DevBio, PreLab 2 - Developmental...

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