Describe the structure of a phospholipid use the term polar and nonpolar in your answer

Key Points

# Phospholipids consist of a glycerol molecule, two fatty acids, and a phosphate group that is modified by an alcohol.

# The phosphate group is the negatively-charged polar head, which is hydrophilic.

#The fatty acid chains are the uncharged, nonpolar tails, which are hydrophobic.

#Since the tails are hydrophobic, they face the inside, away from the water and meet in the inner region of the membrane.

#Since the heads are hydrophilic, they face outward and are attracted to the intracellular and extracellular fluid.

#If phospholipids are placed in water, they form into micelles, which are lipid molecules that arrange themselves in a spherical form in aqueous solutions.

Terms:

#micelleLipid molecules that arrange themselves in a spherical form in aqueous solutions.

#amphipathicDescribing a molecule, such as a detergent, which has both hydrophobic and hydrophilic groups.

:Defining Characteristics of Phospholipids:

Phospholipids are major components of the plasma membrane, the outermost layer of animal cells. Like fats, they are composed of fatty acid chains attached to a glycerol backbone. Unlike triglycerides, which have three fatty acids, phospholipids have two fatty acids that help form a diacylglycerol. The third carbon of the glycerol backbone is also occupied by a modified phosphate group However, just a phosphate group attached to a diacylglycerol does not qualify as a phospholipid. This would be considered a phosphatidate (diacylglycerol 3-phosphate), the precursor to phospholipids.