The cause of less negative RMP of SA node is that the cell membranes of the sinus fibers are naturally leaky to sodium and calcium ions.

TLS Online TPP Program

#Id: 7604

#Unit 5. Developmental Biology

MMP2 is a protein that digests extracellular matrices (such as the zona) and may be responsible for digesting a pathway to the oocyte Acrosin bind secondarily to the zona, keeping the sperm in the channel it creates

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#Id: 7605

#Unit 5. Developmental Biology

The acrosome reaction, exposes the inner acrosomal membrane to the outside. The junction between this inner acrosomal membrane and the sperm cell membrane is called the equatorial region, and this is where membrane fusion between sperm and egg begins

TLS Online TPP Program

#Id: 7606

#Unit 5. Developmental Biology

Gamete fusion involve proteins: Izumo, originally in the acrosomal membrane Juno, an oocyte membrane protein

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#Id: 7607

#Unit 5. Developmental Biology

TLS Online TPP Program

#Id: 7608

#Unit 5. Developmental Biology

Mutations in either Juno or Izumo block fertilization

TLS Online TPP Program

#Id: 7609

#Unit 5. Developmental Biology

Slow Block to polyspermy

When the cortical granules fuse with the egg cell membrane, they release protein-digesting enzymes that modify the zona pellucida proteins such that they can no longer bind sperm