Bulk transport is a type of energy-based transport that includes moving huge amounts of material across plasma membranes, such as lipid droplets and solid food particles.
Active transport is the movement of molecules against a gradient or other type of resistance, such as from a lower to a higher charge area.
Chemicals are transferred across cell membranes without the need for energy in passive transport.
Macrophages are a dramatic example of mass transfer, and most cells in the body do not swallow whole microorganisms.
However, most cells have certain mass transfer mechanisms.
These mechanisms allow cells to obtain nutrients from the environment, selectively "grab" specific particles from the extracellular fluid, and release signaling molecules to communicate with their neighbors.
Similar to the active transport process of moving ions and small molecules between carrier proteins, mass transport is an energy-intensive process.