Question

does every living cell contain phospholipid ?bacteria? Archaea? fungus? animal?

Answer 1

phospholipid is a lipid molecule. It is the main component of the majority of the cell membranes. Every phospholipid molecule is composed of two fatty acids, a glycerol and a phosphate group. Due to their hydrophobic nature they line up and form double layer.

Bacteria- The plasma membrane of bacteria contains phospholipid bilayer.It has all the functions of cell membrane. Due to its permeability barrier it performs many functions like transport of molecules, biosynthesis and energy transduction. Prokaryotic membrane also act as a energy consevation location. Many sugar molecules, ions and amino acids are present in the periplasm ( the region between outer membrane and cytoplasmic membrane ). In the lipid bilayer the lipid portion of the outer layer is impermeable to charged molecules but porins are present in the outer membrane that allows the passive transport of these molecules.

So bateria contains phopholipid.

Archaea- Archaea means prokaryotes. Their structure is very similar to bacteria. The cell membrane of archaea have also phopholipids but they have some unique feature-

1. They have glycerol-ether lipids. in bacteria and eukaryotes have glycerol-ester lipids. It means in archaea lipids are join to glycerol with ether bond.

2.The stereochemistry of the archaeal glycerol molecules is the mirror image of the glycerol molecule of other organisms. The two glycerols are mirror images of one another, called enantiomers. Just as a right hand does not fit easily into a left-handed glove. The archaeal phospholipids are made on a backbone of sn-glycerol-1-phosphate, which is an enantiomer of sn-glycerol-3-phosphate. It means that archaea use purely different enzymes for synthesizing phospholipids as compared to bacteria and eukaryotes. Such enzymes developed very early in life's history.

3.Archaeal lipid tails are different than other organisms in that they are based upon long isoprenoid chains with multiple side-branches. On the other hand, the fatty acids in the membranes of other organisms have straight chains without side branches or rings. Isoprenoids play an important role in the biochemistry of many organisms.  

4. The lipid bilayer is replaced by a monolayer in some archaeas. The archaea fuse the tails of two phospholipid molecules into a single molecule with two polar heads.This fusion may make their membranes more rigid and better.Able to resist harsh environments.

Fungus- Fungi are eukaryotes so they have complex cellular organization. The fungal cell membrane is arranged in a phospholipid bilayer with multiple transmembrane proteins. In fungi, the primary membrane sterol is ergosterol, which is unique in contrast to animals.

Eukaryotes- Eukarotic cytoplasmic membrane also have phospholipids.

Cytoplasmic Membrane

Description: It is also known as plasma membrane or cell membrane. It is a semi-permeable membrane that separates the inside of a cell from the outside.

Structure and Composition: The plasma membrane of eukaryotic cell  consists of proteins, carbohydrates and two layers of phospholipids (i.e. lipid with a phosphate group). The phospholipids have this kind of arrangement-

• The polar and hydrophilic heads faces the outside and inside of the cell. These heads interact with the aqueous environment outside and within a cell.
• The non-polar and hydrophobic tails are sandwiched between the heads and are protected from the aqueous environments.

Scientists Singer and Nicolson described the structure of the phospholipid bilayer as the ‘Fluid Mosaic Model’. The bi-layer looks like a mosaic and has a semi-fluid nature that allows lateral movement of proteins within the bilayer.

So all the living organisms have phospholipids.