Question

compare the hydrophobic and hydrophilic properties of phospholipids and nucleic acids. how does this relate to their structural arrangement in cells?

Answer 1

In biological system, the phospholipids often occur with other molecules are in bilayer such as cell membrane. Lipid bilayer occur when hydrophobic tail line up against one another, forming membrane of hydrophilic heads on both sides facing the water. A phospholipids is an amphipathic molecule which means it has both hydrophobic and hydrophilic components a single phospholipid molecules usually has a phosphate group at one end which is called as head and two side by side chains of fatty acid that make up the lipids tail.The hydrophilic heads of phospholipids in a membrane forms a bilayer that faces outwards, contacting the fluid both inside and outside of cell the hydrophobic usually known as water-fearing forms a part of a phospholipids which consist of long, non polar fatty acid tails.

The most important function of phospholipid is form phospholipid bilayer. In that bilayer this phospholipids are arranged such that all hydrophilic heads are pointing outwards and hydrophobic tails are pointing inwards.

In phosphodiestr bonds link successive nucleotides in nucleic acids these successive nucleotides of both DNA and RNA molecules are covalently linked through phosphate groups and hydrophilic forms a backbone of both DNA and RNA.

The hydroxyl group of sugar tends to form hydrogen bond with water . The hydrophilic phosphate heads like water so they get touched from inside and outside of cells and environment remains watery. Then the hydrophobic region in the middle which is free from water.Thus the cell membrane help in structuring the cell and also controls substance to cross.

The hydrophilic head pointed out and hydrophobic tail pointed in   when the lipid is in water ,the phospholipid can be flexible and strong. This stable structure with fluidity allows the cell to change shape easily and maintain their structure too.