Question

Cellulose is a:
A. Protein
B. Carbohydrate
C. Simple Sugar
D. All of the above

Answer 1

Hint: Cellulose is an organic molecule consisting of ${\text{100 to 1000}}$ chains mixed up of carbon, hydrogen and oxygen atoms in the form of polysaccharide. It is found in the walls of plant cells and humans are not capable of digesting it.

Complete step by step answer:
Cellulose is a polysaccharide made from polymerisation of several monomer units of ${\text{D - Glucose}}$. Its formula is ${\left( {{C_6}{H_{10}}{O_5}} \right)_n}$.
-Protein - Proteins are the chains of amino acids which are linked together by peptide bonds or linkages but cellulose is made up of polysaccharide chains of ${\text{D - Glucose}}$ units linked together by polymerization. Hence, cellulose is not a protein.
-Carbohydrate - Glucose sugar is a carbohydrate and polysaccharide chain of the polymer cellulose made up of several repeating units of the monomer ${\text{D - Glucose}}$. Hence, we can say that cellulose is a carbohydrate. Thus, it is the correct answer.
-Simple Sugar-Simple sugars are the sugar which contains only one monosaccharide unit which cannot be further broken into simpler compounds. Cellulose is a polysaccharide which consists of several repeating units of monosaccharide ${\text{D - Glucose}}$. Thus, it cannot be broken down into simpler compounds. Hence, cellulose is not a simple sugar.
Hence, option (b) is the only correct answer, cellulose is a carbohydrate.

Note: The reason why humans cannot digest raw grass is because raw grass contains cellulose, and the digestive system of humans does not have necessary enzymes to digest cellulose. That’s why animals can digest raw grass but humans cannot.