Why can proteins and carbohydrates be categorized as macromolecules as well?
aren't both polymers of monomers?
Because of their size. They are large.
Proteins and carbohydrates can be categorized as macromolecules because they are both composed of large numbers of smaller subunits. Macromolecules are generally defined as large molecules that consist of repeating units called monomers. In the case of proteins, the monomers are amino acids, while for carbohydrates, the monomers are simple sugars (monosaccharides).
To understand why proteins and carbohydrates can be categorized as macromolecules, let's take a closer look at their structure and how they are formed:
1. Proteins:
- Proteins are composed of long chains of amino acids that are linked together by peptide bonds. Each amino acid consists of an amino group (-NH2), a carboxyl group (-COOH), and a side chain (R-group) that varies among the 20 different amino acids.
- When multiple amino acids are joined together by peptide bonds, they form a polypeptide chain. These chains can be hundreds or even thousands of amino acids long, resulting in a complex and large molecule.
- The specific sequence of amino acids in the polypeptide chain determines the protein's unique structure, function, and properties.
2. Carbohydrates:
- Carbohydrates are composed of carbon, hydrogen, and oxygen atoms. They are typically classified as monosaccharides, disaccharides, or polysaccharides, depending on the number of sugar units they contain.
- Monosaccharides are the basic building blocks of carbohydrates. Examples include glucose, fructose, and galactose. They have a simple molecular structure and cannot be broken down into smaller sugar units.
- Disaccharides consist of two monosaccharides joined together by a glycosidic bond. Examples include sucrose (glucose + fructose) and lactose (glucose + galactose).
- Polysaccharides are large molecules composed of long chains of monosaccharide units. Examples include starch and cellulose in plants, and glycogen in animals. These chains can be branched or linear and can contain thousands of monosaccharides.
Overall, proteins and carbohydrates can be categorized as macromolecules because they are both formed by the repetition of smaller monomeric units. Proteins are formed from amino acids linked in a chain, while carbohydrates are formed from sugar units (monosaccharides) connected together. Their large and complex structures enable them to perform their vital biological functions.