Assume That the Import of a Particular Amino Acid Across

Multiple Choice

Assume that the import of a particular amino acid across the plasma membrane is observed (1) to occur onlydown its concentration gradient and (2) to slow when a different but similar amino acid is added to the extracellular fluid. The movement of the amino acid through the membrane is most likely by

A) osmosis.
B) diffusion.
C) facilitated diffusion.
D) active transport.
E) pinocytosis.