Question

Rhamnose and galacturonic acids are found as chief components of
(a) Lignin
(b) Pectin
(c) Suberin
(d) Glucose

Answer 1

Hint: One of the most important polysaccharides and a component of the cell wall derived from the carbohydrate called galactose. It is used in also medicine and the food industry

Complete answer:
Acidic polysaccharide present in the primary and middle lamella and cell walls of terrestrial plants is called pectin. It is made up of galacturonic acid derived from a carbohydrate called galactose. Galacturonic acid is the main component in pectin. Along with galacturonic acid other polysaccharides present in pectin are D-galactose, L-arabinose, and D-xylose, L-rhamnose, etc.

Additional Information: - Pectin consists of complex polysaccharides such as Galacturonic acid, D-galactose, L-arabinose and D-xylose, L-rhamnose, etc present in most primary cell walls particularly found in woody terrestrial plants
- Middle lamella consists of pectin that helps in the binding of cells which is deposited by exocytosis
- it is one of the important cell wall polysaccharides that helps in cell wall extinction and cell growth
- Pectin is also a natural part of the diet in humans but is not an important source of nutrition. It helps in slowing down the process of absorption of glucose by binding to cholesterol in the gastrointestinal tract
- p-coumaryl alcohol, coniferyl alcohol, and sinapyl alcohol are the chief components of lignin that is synthesized by polymerization of these compounds. It helps in the transportation of water, gives mechanical support and resistance to various stress for the cell
- Aliphatic and aromatic compounds are the chief constituent of suberin which is a lipophilic molecule. It helps the plant cell to overcome insulation or need protection from the surroundings.
- Glucose is a monosaccharide formed from disaccharides like sucrose which is the main energy source for most of the cells in an organism. Glucose is one of the chief carbohydrates
So, the correct answer is ‘pectin’

Note: -Pectin is used as a thickening agent, gelling agent, and stabilizer in food.
-It increases viscosity and volume of stool, so medicine is used against diarrhea and constipation.
-Henri Braconnot in 1825, first time isolated and discovered pectin.