Starch is a long, straight chain of glucose units, whereas glycogen is a branched chain of glucose units.
Structure of Glycogen
Proteins are polymers of amino acids.
Amino acids all have the general structure:
The R in the diagram represents a functional group that varies depending on the specific amino acid in question.
Twenty amino acids in human metabolism
When 2 amino acids bond together, water is released as the carboxyl end of one amino acid bonds to the amine end of the adjacent one forming a peptide bond, as illustrated at the left.
Because water is lost, the process is called:
Condensation synthesis, or…
When many amino acids bond together to create long chains, the structure is called a protein (it is also called a polypeptide because it contains many peptide bonds).
Proteins are large molecules that may consist of hundreds, or even thousands of amino acids.
Proteins are important in cell structure, as enzymes, which speed up reactions in the body, and as antibodies which fight infection
Fats are a sub-group of compounds known as lipids that are found in the body and have the general property of being hydrophobic (meaning they are insoluble in water).
Other lipids include waxes, and steroids, such as cholesterol.
Fats are also known as triglycerides, molecules made from the combination of one molecule of glycerol with three fatty acids.
“R” is a long chain of carbon and hydrogen
Fats are concentrated forms of energy storage
9 calories per gram
Fats are components of cell membranes