The genetic code, in effect, is defined by two elements:

(1) the anticodons on tRNAs

(2) the specificity of the enzymes.

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#Id: 7587

#Unit 5. Developmental Biology

Connection between sperm translocation

and capacitationbefore entering the ampulla of the oviduct, the uncapacitated sperm bindactively to the membranes of the oviduct cells in the the isthmus) & this bindingis temporary and appears to be broken when the sperm become capacitated

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#Unit 5. Developmental Biology

Toward the end of capacitation, sperm become hyperactivated—The symmetrical beating of the flagellum is changed into a rapid asynchronous beat with a higher degree of bending. 

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#Unit 5. Developmental Biology

Hyperactivation mediated by the opening of the sperm specific calcium channels, the CatSper proteins, in the sperm tail.

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#Unit 5. Developmental Biology

Once a sperm has reached the oocyte-cumulus complex, hyperactivation, along with a hyaluronidase enzyme on the outside of the sperm cell membrane, enables the sperm to digest a path through the extracellular matrix of the cumulus cells

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#Unit 5. Developmental Biology

Thermotaxis  The ability to sense temperature difference and preferentially swim from cooler to warmer sites is found only in capacitated sperm

 

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#Id: 7592

#Unit 5. Developmental Biology

Capacitated mammalian sperm can sense thermal differences as small as 0.014 degrees Celsius over a millimeter and tend to migrate toward the higher temperature