What macromolecules in the plasma membrane are most directly responsible for transporting large. polar molecules into or out of the cell?
carbohydrates
nucleic acids
phospholipids
proteins

Proteins

Explanation:

There are proteins in the membrane that have channels for large polar molecules to move into or out of the cell since the plasma membrane is made of a phospholipid bilayer where the inside is non polar. This means large polar molecules need help from proteins to cross the plasma membrane.