The transition from specification to determination in Drosophila is mediated by Segmentation genes.

TLS Online TPP Program

#Id: 7576

#Unit 5. Developmental Biology

Sperm that are not capacitated are “held up” in the cumulus matrix and are unable to reach the egg

TLS Online TPP Program

#Id: 7577

#Unit 5. Developmental Biology

Capacitation is a transient event, and sperm are given a relatively brief window of competence during which they can successfully fertilize the egg. As the sperm reach the ampulla, they acquire competence—but they lose it if they stay around too long

TLS Online TPP Program

#Id: 7578

#Unit 5. Developmental Biology

The molecular processes of capacitation prepare the sperm for the acrosome reaction and enable the sperm to become hyperactive

TLS Online TPP Program

#Id: 7579

#Unit 5. Developmental Biology

Capacitation

The sperm cell membrane

is altered by the removal of

cholesterol by albumin proteins in the female reproductive tract

TLS Online TPP Program

#Id: 7580

#Unit 5. Developmental Biology

The cholesterol efflux from the sperm cell membrane is thought to change the location of its “lipid rafts,” contain receptor proteins that can bind the zona pellucida and participate in the acrosome reaction

TLS Online TPP Program

#Id: 7581

#Unit 5. Developmental Biology

Particular proteins or carbohydrates on the sperm surface are lost during capacitation because these compounds block the recognition sites for the sperm proteins that bind to the zona pellucida