AP BIOLOGY

Detailed explanation-1: -The cell membrane, therefore, has two functions: first, to be a barrier keeping the constituents of the cell in and unwanted substances out and, second, to be a gate allowing transport into the cell of essential nutrients and movement from the cell of waste products.

Detailed explanation-2: -Protein machineries embedded in the membranes of our cells act as ‘gatekeepers’ controlling everything transported in and out of every cell in our bodies. Because these machineries, called membrane embedded proteins, are vital to the way our bodies function they are the target of at least 40% of drugs.

Detailed explanation-3: -The two major components of cell membranes are phospholipids and protein. Phospholipids are a unique type of lipid that have both hydrophilic and hydrophobic parts.

Detailed explanation-4: -Cell membranes serve as barriers and gatekeepers. They are semi-permeable, which means that some molecules can diffuse across the lipid bilayer but others cannot.