Question

(t or f) small, hydrophilic molecules cannot just flow into the cell, they need help to pass through the plasma membrane

Answer 1

True. The plasma membrane is made up of a phospholipid bilayer and a hydrophobic core. Hydrophilic molecules are thus unable to pass through the hydrophobic core and often need the help of transporter proteins or carrier proteins to pass through, or if it is a signalling molecule, it will utilise receptors to pass the signal into the cell.