Final answer:
Amino acids are the basic building blocks of proteins, with each molecule containing an amino group and a carboxyl group attached to a central alpha carbon, along with a variable side chain.
Step-by-step explanation:
The basic building block of proteins, which contains a carboxyl group (-COOH) and an amino group (-NH2), is known as an amino acid. These molecules are essential to life and serve as the monomers for proteins. Each amino acid has a central alpha (a) carbon to which an amino group, a carboxyl group, a hydrogen atom, and a variable side chain (R group) are attached. This structure makes amino acids uniquely suited to form the diverse range of proteins found in living organisms.
There are 20 common amino acids that combine in various sequences to form proteins. Each of these amino acids shares the same fundamental structure, which enables them to link together through peptide bonds, creating the complex three-dimensional structures necessary for protein function.