Thinkquest
Intro
Nucleic Acids
Amino Acids
Lipids
Water
Acknowledgements
About Us
Properties of Water
Life would not have existed on earth without water. Water molecules are composed of one oxygen atom and two hydrogen atoms. Together, the hydrogen and oxygen molecules form a shape that resembles the head of Mickey Mouse.
While water molecules seem to be simple compounds, their properties have profound impact on life. Because of the arrangement of hydrogen and oxygen atoms, water molecules have polarized charges (one end is positive and the other end is negative). Due to their polarized nature, 2 adjacent water molecules can form a linkage via a hydrogen bond.
The most important function of fatty acid is its ability to combine to form uniform bilayers of lipid (to prevent the hydrophobic region from being exposed). These lipid bilayers are used to form the impermeable cell membrane and helped to define the first cell . The hydrophobic property of lipid membrane also allows the cell to facilitate transport of molecules.
The polarized nature of water causes other molecules to be either hydrophilic (like water) or hydrophobic (afraid of water). This property allows certain molecules to dissolve in water while preventing others from entering the cell. For example, hydrophobic interaction can hold molecules together.
Osmosis
Another important property of water is its ability to facilitate the transfer of molecules through osmosis. When 2 aqueous solutions are separated by a membrane that only allows the passage of water molecules, water will move from the less concentrated to the more concentrated side