AP BIOLOGY

Detailed explanation-1: -Companion cells, on the other hand, contain many mitochondria. And so it is these cells that provide the energy needed for translocation.

Detailed explanation-2: -noun. : a living nucleated cell that is closely associated in origin, position, and probably function with a cell making up part of a sieve tube of a vascular plant.

Detailed explanation-3: -Function of companion cell is to load sugar and amino acids into sieve elements. These cells use transmembrane proteins to take up these molecules by active transport.

Detailed explanation-4: -Companion cells-transport of substances in the phloem requires energy. One or more companion cells attached to each sieve tube provide this energy. A sieve tube is completely dependent on its companion cell(s).

Detailed explanation-5: -Phloem is comprised of cells called sieve-tube elements. Phloem sap travels through perforations called sieve tube plates. Neighboring companion cells carry out metabolic functions for the sieve-tube elements and provide them with energy.