keep a civil tongue in one's head. Speak politely, as in The teacher won't allow swearing; she says we must keep a civil tongue in our heads. This expression uses tongue in the sense of a manner of speaking, a usage dating from the 1400s. An early cautionary version was Keep a good tongue in your head, lest it hurt your teeth (1595). See also: civil, head, keep, tongue. n. a civil servant.
Phospholipids serve a major function in the cells of all organisms: they form the phospholipid membranes that surround the cell and intracellular organelles such as the mitochondria. The cell membrane is a fluid, semi-permeable bilayer that separates the cell's contents from the environment, see animation below.hospholipids serve a major function in the cells of all organisms: they form the phospholipid membranes that surround the cell and intracellular organelles such as the mitochondria. The cell membrane is a fluid, semi-permeable bilayer that separates the cell's contents from the environment, see animation below.
Phospholipids are the main constituents of cell membranes. Their function as the principle components of cell membranes makes phospholipids essential for all vital cell processes. Phospholipids are the most important membrane building compounds that occur in human, animal and plant cells.All biological membranes consist primarily of phospholipids and proteins. Phospholipids are amphophilic molecules with unique physicochemical properties. just now. Report Abuse. Phospholipids make up the structure of the lipid bilayer found in the membrane of cells. Primarily, it's main job is to keep the things that are on the inside of a cell inside, and keep what things are outside the cell on the outside.