Junctions between the plasma membranes of adjacent cells in animals that form a barrier, preventing materials from passing between the cells. Groups of cells performing a function in a multicellular organism. Any indication of prehistoric organic activity, such as tracks, trails, burrows, or nests. Long, tapered cells with pitted walls that form a system of tubes in the xylem and carry water and solutes from the roots to the rest of the plant. One type of xylem cells.
Tracheids are long and relatively narrow, and transport materials from the roots upward.
Tracheids are dead at maturity and have lignin in their secondary walls. The synthesis of RNA from a DNA template. The making of RNA from one strand of the DNA molecule. Small, single-stranded RNA molecules that bind to amino acids and deliver them to the proper codon on messenger RNA . The trucks of protein synthesis that carry the specified amino acid to the ribosome .