Developmental Exam 1

When the Membrane Binding Proteins that surround the sperm head concentrate around the tip of the sperm head, which becomes the contact point for the egg & sperm.  It occurs when there is a cholesterol eflux from the sperm, which creates big pores within the plasma membrane.  cholesterol has OH groups that fit in the plasma layer perfectly.

• 1. Egg & Sperm Recognition
• 2. Capacitation
• 3. Chemotaxis

It is necessary to make the sperm more motile.  Sperm must be activated and it must occur within the female reproductive tract.

- Sperm must enter the female reproductive tract, where it travels through a LOW CO2 and High pH BASIC, which causes Na+ influx and H+ eflux.

Immobile sperm enters the female reproductive tract which is BASIC and LOW CO2 conentration this cause a Na+ influx & H+ eflux spearact from the egg binds to its receptor in the sperm head which activates second messenger GTP to activate guanylate cyclase resulting in cGMP.  This cause a K+ eflux, resulting in the hyperpolarization of the spermhead (because it is becoming slightly more negative)  CREB binds to cAMP activating it as the spermhead tries to neutralize its pH with the Na+ & H+ influx & eflux.  With the activation of cAMP transcription factors get going & Ca2+ influx is created, Na/K pumps are opened kicking out 2K's for every 3Na's.  the ova then makes and releases ZP1,ZP2, & ZP3 proteins, when the ZP3 protein & receptor bind together carbohydrates come in and contaminate the membrane, preventing polyspermy, and Ca+/T-channels are activated which create a Ca+ influx (in the egg?)

- they do not bind tightly, which means that they can fall off.

Very Species Specific.  In sea urchins it is a protein on the sperm's acrosome surface that mediates fusion to the sea urchin egg.

May activate Acrosome Rxn, and used for sperm-egg recognition

protein in egg membrane; 10 amino acids long

protein on the egg surface; 14 amino acids long

in the sperm

• 1. spearact
• 2. resact

• ZP1
• ZP2
• ZP3

in the sperm & acrosome

• Occurs on both egg & sperm sides
• Receptor Ligand Driven
• Occurs very quickly
• Huge Ion Influx
• Increase in Membrane fluidity (b/c of Ca Eflux)

Generic Binding Protein/Controller/Transcription Factor located on the 3' end

Specific Binding Proteins/Transcription Factors that bind tightly

a binding protein that controls the flow of gene inflo

ZP3 becasue the sperm is attracted to the ZP3 protein and actually gravitates toward it.

ZP2 & ZP3

ZP1 & ZP2

- when ZP3 & its receptor bind they cause carbohydrates to come in & contaminate the egg membrane

Another word for Ca+ Channel

• - Ca2+
• - fusion of sperm & egg membranes

• -Aquorin
• -Indole 3
• -Furan 2

RECEPTOR-LIGAND INTERACTION WITH MUSCARINIC RECEPTORS OF THE ZP3


ACTIVATION OF G-PROTEIN CREATES A TRIMER THAT KICKS OUT GDP & TAKES IN GTP.  THE ALPHA SUBUNT ALONG WITH GTP DISSOCIATES ALONG THE CELL MEMBRANE WHICH THEN TARGETS adenyl cyclase & phosphotidal inosital (PI-PLC)

Adenyl Cyclase Activation by ATP produces cAMP +PO4

GDP

because female mammals are selective maters

because of external fertalization.  Mates are not choosy.