AP BIOLOGY

Detailed explanation-1: -Phloem cells Adaptations: Made of living cells (as opposed to xylem vessels, which are made of dead cells) that are supported by companion cells. Cells are joined end-to-end and contain holes in the end cell walls (sieve plates) forming tubes which allow sugars and amino acids to flow easily through (by translocation)

Detailed explanation-2: -Companion cells are found in the phloem of flowering plants. These are specialized parenchyma cells They are nucleated cells with ribosomes and mitochondria.

Detailed explanation-3: -Companion cells are found along with sieve tube elements in the phloem. The main function of companion cells is to maintain pressure gradient in the sieve tube elements.

Detailed explanation-4: -companion cell A type of cell found within the phloem of flowering plants. Each companion cellis usually closely associated with a sieve element. Its function is uncertain, though it appears to regulate the activity of the adjacent sieve element and to take part in loading and unloading sugar into the sieve element.