Q. 13.48 - An Introduction to General, Organic, and Biological Chemistry

Question

Describe the similarities and differences in the following:

a. amylose and cellulose

b. cellulose and glycogen

Step-by-Step Solution

Answer

Part a). Both are polymers of glucose and the difference is animals can digest amylose, but they cannot digest cellulose.

Part b). Both are polymers of glucose and the difference is cellulose cannot be digested by animals, but glycogen is converted to glucose in animals according to their needs.

Step 1: Amylose and cellulose (Part a)

• Amylose is necessary for the storage of energy in plants. It takes longer to digest than amylopectin.
• Cellulose is a sort of molecule that is made up of hundreds or thousands of carbon, hydrogen, and oxygen atoms.

Step 2: Similarities between amylose and cellulose (Part a)

• Both amylose and cellulose are glucose polymers.
• Both are carbohydrates derived from plants.
• Both polysaccharides are unbranched.

Step 3: Difference between amylose and cellulose (Part a)

• Amylose has just $\alpha -1,4$-glycosidic bonds, whereas cellulose has $\beta -1,4$ glycosidic bonds connecting glucose units.
• Plants' storage carbohydrate is amylose, while their structural substance is cellulose.
• Animals can digest amylose, but they cannot digest cellulose.
• Amylase polymers are coiled in a helical pattern, but unbranched chains in cellulose are arranged in parallel rows and bound together by hydrogen bonds.

Step 4: Cellulose and glycogen (Part b)

• Cellulose is a molecule made up of hundreds, if not thousands, of carbon, hydrogen, and oxygen atoms.
• Glycogen is form of glucose polysaccharide which is found in most mammalian and nonmammalian cells, as well as microbes and plants.

  

Step 5: Cellulose and glycogen's similarities and differences (Part b)

The following is the similarities between cellulose and glycogen:

•  Both cellulose and glycogen are glucose polymers.

The following are the differences between cellulose and glycogen:

• Glycogen is a branched polysaccharide, whereas cellulose is an unbranched carbohydrate.
• Only $\beta -1,4$-glycosidic linkages exist in cellulose, whereas $\alpha -1,4$ and $\alpha -1,6$ glycosidic bonds exist in glycogen.
• Cellulose cannot be digested by animals, but glycogen is converted to glucose in animals according to their needs.
• Plants use cellulose as a structural carbohydrate, but animals use glycogen as a storage form of glucose.