Â© Ted French. Definition: A function is a preset formula in Excel and Google Spreadsheets. Like formulas, functions begin with the equal sign (=) followed by the function's name and its arguments. The function name tells Excel what calculation to perform. The arguments are contained inside round brackets.
Best Answer: Look for molecular symmetries. Symmetrical molecules such as methane, carbon dioxide, carbon disulfide, and borane (BH3) are nonpolar. Asymmetric molecules such as water, ammonia, and acetone are polar.
Since a lipid molecule contains regions that are both polar and nonpolar, they are called amphipathic molecules. The most abundant class of lipid molecule found in cell membranes is the phospholipid. The phospholipid molecule's polar head group contains a phosphate group. It also sports two nonpolar fatty acid chain groups as its tail. Figure %: Phospholipid Structure.