Which type of membrane protein spans the entire width of the membrane?

Which of the following typically describes molecules that easily diffuse through the plasma membrane (lipid bilayer) of animal cells?

What is the name for dense microdomains of the plasma membrane that are enriched in cholesterol and sphingolipids and are centers for signal molecule assembly and receptor trafficking?

Dense specialized plasma membrane microdomains that cluster cholesterol, sphingolipids, and protein receptors, and are also sites of receptor trafficking and assembly of signal molecules, are called __________.

Many retroviruses, including (human immunodeficiency virus) HIV and other lentiviruses, generally bind what structure on the plasma membrane of vertebrate cells?