Question

What are the basic units of all carbohydrates?

Answer 1

Carbon and water are the basic unit of carbohydrates. The word meaning of carbohydrate is ${\text{carbohydrate}}$. Hydrate means nothing but water. As we know that these carbohydrates are also known as saccharides. The word meaning of saccharides is sugar. In the human body carbohydrates are stored as glycogen. Plant carbohydrates store starch. It is the main source of energy for human beings.

Complete step by step answer:
We have to know that the basic functional unit of carbohydrates is ${\text{C}}{{\text{H}}_{\text{2}}}{\text{O}}$. It is a combination of carbon and water. The monomer unit of carbohydrate is ${\text{C}}{{\text{H}}_{\text{2}}}{\text{O}}$. Glucose well known and simplest example for carbohydrate. The chemical formula of glucose is ${{\text{C}}_{\text{6}}}{{\text{H}}_{{\text{12}}}}{{\text{O}}_{\text{6}}}$. The simplest representation of glucose molecule is ${{\text{(C}}{{\text{H}}_{\text{2}}}{\text{O)}}_6}$.
We have to know that any carbohydrates can express in their basic unit like ${{\text{(C}}{{\text{H}}_{\text{2}}}{\text{O)}}_n}$. Here n is nothing but the number of carbon atoms in the carbohydrates.

additional Information: Carbohydrates are classified as three major groups. This classification is based on the hydrolysis of carbohydrates. There are monosaccharides, oligosaccharides and polysaccharides. Monosaccharides means here only one carboxylic group in the molecule. Respect that carboxylic group hydrolysis will happen. Glucose, fructose are examples of monosaccharides. Lactose and maltose are examples of oligosaccharides, because they contain more than one functional monomer in the structure. Starch, glycogen and cellulose are the examples of polysaccharides because they have more than three monomers in the structure.

Note: We have to remember that the carbohydrates are classified as two types. This classification is based on the functional monomer in the carbohydrates. In carbohydrates aldehyde and ketone act as monomers. According to that carbohydrates are separated as aldose and ketose.
Carbohydrates also classified as many types depend on the number of the carbon atoms. Depending on the value of n $(3,4,5,6,...)$ are classified as (trioses, tetroses, pentoses, hexoses etc…).