A plough (UK) or plow (US; both /ËplaÊ/) is a tool or farm implement used in farming for initial cultivation of soil in preparation for sowing seed or planting to loosen or turn the soil. Ploughs were traditionally drawn by working animals such as horses or cattle, but in modern times are drawn by tractors.
Polar/Nonpolar Regions. In a biological membrane, the phospholipids are organized into a bilayer, which serves as the framework in which the other components of the membrane are embedded.
The hydrophilic (water loving) polar heads of. the phospholipid molecules face the outside and inside of. the cell where water is found, and the hydrophobic (water. fearing) nonpolar tails face each other (Fig. 4.1). In. addition to phospholipids, there are two other types of. lipids in the plasma membrane.