The cell walls of a plant consist mostly of cellulose, a carbohydrate, which provides a strong structure. The cell membrane gets its structure primarily from lipids, and embedded proteins allow for material transport. Which of the following elements would be found in the LOWEST amounts in both the cell wall and cell membrane?

The answer is Sodium (Na+)

Explanation: The cell wall of the plant cells is composed mostly of cellulose, which is a polysaccharide composed mostly of carbon, hydrogen and oxygen, and it has a linear and complex configuration. On the other hand, the cell membrane is composed of phospholipids, in the configuration of lipid bilayer. Phospholipids are molecules that have a polar head (where phosphorus is found) and a hydrophobic (lipid) tail. Carbon and hydrogen are also found in non-polar or hydrophobic tails. Sodium on the other hand is an Ion (Na +) that is mainly dissolved in water, so it is expected to find it mostly in the lumen or outside the cell. Sodium plays an important role in the transport of some substances through the cell membrane, but their amounts cannot be very high, because of being very concentrated, this can cause plasmolysis or cell destruction