The SNP mutation responsible for sickle-cell disease changes amino acid 6 in haemoglobin β from glutamic acid (E) to valine (V). 

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

TLS Online TPP Program

#Id: 7582

#Unit 5. Developmental Biology

The membrane potential of the sperm cell becomes more negative as potassium ions leave the sperm. 

TLS Online TPP Program

#Id: 7583

#Unit 5. Developmental Biology

Negative membrane potential may allow calcium channels to be opened and permit calcium to enter the sperm. 

TLS Online TPP Program

#Id: 7584

#Unit 5. Developmental Biology

Calcium and bicarbonate ions are critical in activating cAMP production and in facilitating the membrane fusion events of the acrosome reaction

TLS Online TPP Program

#Id: 7585

#Unit 5. Developmental Biology

The influx of bicarbonate ions (and possibly other ions) alkalinizes the sperm, raising its pH. This will be critical in the subsequent activation of calcium channels