#Question id: 5678
#Unit 5. Developmental Biology
Following process and their mechanism during fertilization in mammals.
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a. Rheotaxis |
i.A sensing mechanism in which, the oocyte and its accompanying cumulus cells secrete molecules that attract capacitated sperm toward the egg during the last stages of sperm migration |
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b. Chemotaxis |
ii.It is a transient event, and sperm are given a relatively brief window of competence during which they can successfully fertilize the egg. |
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c. Capacitation |
iii.it is the ability to sense temperature difference and preferentially swim from cooler to warmer sites is found only in capacitated sperm. |
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d. Thermotaxis |
iv.Sperm receive long-distance directional cues from the flow of liquid from the oviduct to the uterus and they will migrate against the direction of the flow—using CatSper calcium channels to sense calcium influx and monitor the direction of the current |
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Which of the following option is correct?
#Question id: 5679
#Unit 5. Developmental Biology
Following statements regarding to the molecular processes of capacitation.
A. The sperm cell membrane is altered by the removal of albumin by cholesterol in the female reproductive tract.
B. Particular proteins or carbohydrates on the sperm surface are lost during decapacitation.
C. The membrane potential of the sperm cell becomes more positive as potassium ions leave the sperm. This change in membrane potential may allow calcium channels to be opened and permit calcium to enter the sperm.
D. Calcium and bicarbonate ions are critical in activating cAMP production and in facilitating the membrane fusion events of the acrosome reaction.
E. As a result of cAMP formation, protein phosphorylation occurs. Once they are phosphorylated, some proteins migrate to the surface of the sperm head. One of these proteins is izumo, which is critical in sperm-egg fusion.
which one of the following combinations is correct?
#Question id: 5680
#Unit 5. Developmental Biology
In vitro model of species-specific binding shows in figure. Add the bindin particles to a plastic well containing a suspension of eggs. After 2–5 minutes of gentle shaking, the wells were photographed.
According to this figure, which of the following conclusion correctly define the phenomenon of species specificity?
#Question id: 5681
#Unit 5. Developmental Biology
What is the arrangement of microtubules in sperm flagellum?
#Question id: 5682
#Unit 5. Developmental Biology
During prevention of polyspermy in sea urchin the shift from ___1___ to __2____is the result of a small influx of Na+ into the egg through newly opened sodium channels. Sperm cannot fuse with egg cell membranes that have a ___3___ resting potential, so the shift means that no more sperm can fuse to the egg.
#Question id: 5683
#Unit 5. Developmental Biology
There may be an important connection between sperm translocation and capacitation. Which of the following option is correct explanation of above statement?