Question

1. The orientation of phospholipids in water occurs spontaneously. Why?

2.You board the Magic School Bus and go on a microscopic adventure to visit the plasma membrane of a cell. All of a sudden, the temperature dropsand the cell membrane starts to get too solid!!! Oh no! To combat this decrease in fluidity, the cell starts firing new phospholipids up to the plasma membrane! What would the composition of these lipids look like (i.e. saturated vs unsaturated fatty acids, cholesterol?)

3.How do cells overcome the energy requirement of active transport?

Answer 1

1. The orientation of phospholipids will occur spontaneously because phospholipids are polar. They have a hydrophilic head and a hydrophobic tail. Hydrophilic head faces towards water and hydrophobic tail faces inside. So, this happens spontaneously. Hydrophilic is water loving and hydrophobic is water fearing.

2. As there is decrease in fluidity cell will try to increase the fluidity. To increase the fluidity more unsaturated lipids will be added to the plasma membrane. So, more unsaturated fatty acids will be added to the plasma membrane.