AP BIOLOGY

Detailed explanation-1: -Proteins and polysaccharides that are too large to move into a cell through diffusion or active transport move in by: a. exocytosis.

Detailed explanation-2: -The movement of macromolecules such as proteins or polysaccharides into or out of the cell is called bulk transport. There are two types of bulk transport, exocytosis and endocytosis, and both require the expenditure of energy (ATP). In exocytosis, materials are exported out of the cell via secretory vesicles.

Detailed explanation-3: -Diffusion, osmosis and facilitated diffusion are passive means to get things across the membrane. There are energy consuming means also. The really big stuff (e.g. proteins and polysaccharides) does not get in and out of a cell by passing through the membrane.

Detailed explanation-4: -Proteins cannot passively diffuse across the cell membrane due to their size and polarity. Thus, a delivery system or technique is always required, similar to nucleic acid transfection.

Detailed explanation-5: -Carrier proteins bind specific solutes and transfer them across the lipid bilayer by undergoing conformational changes that expose the solute-binding site sequentially on one side of the membrane and then on the other.