Category: Biology Second Paper

Chitin is a polysaccharide. A simple linear homopolymer of N-acetyl-D-glucosamine residues is called chitin. Chitin is one of the most abundant substances on earth. It is the second most important polymer in the world. Its chemical symbol is (C8H13O5)n. Numerous D amino monomers are joined by β-1, 4 glycosidic bonds to form chitin.
Properties of chitin
(i) Chitin is insoluble in water, organic acids and weak acids.
(ii) It is soluble in strong formic acid and methane sulphonic acid.
(iii) It is stronger and more stable than cellulose.
(iv) Chitin is decomposed by strong acids to acetic acid and u-amino glucose.
(v) It is similar to keratin protein.
Source of Chitin: Chitin forms the exoskeleton or shell of animals like moths, crabs, shrimps, lobsters, squids. The cell walls of yeast and fungi are made of chitin. Dr. Siddique Publications
Uses of chitin: Chitin has uses in herbal, industrial and biotechnology.

Inulin is a polysaccharide. It is dissolved in cells. It contains 30-35 fructose units. Plants of the family Asteraceae such as dahlia, chicory, Jerusalem artichoke etc. contain inulin. Inulin is found in onions and garlic.

(i) Stored food: Glycogen is stored in the animal body as stored food.
(ii) Glucose production: Glucose is produced from liver glycogen in the process of glycogenesis.
(iii) Muscle energy: Glycogen stored in skeletal and cardiac muscles provides extra energy to muscles.
(iv) Regulation of blood volume: It regulates blood volume in the body. Increases blood glucose levels by breaking down liver glycogen. Dr. Siddiq Publications
(v) Formation of suspension: It forms colloidal suspension in water.
(vi) Production of Surfactant: Glycogen begins to accumulate in the pulmonary cells of the fetal baby at 23 weeks of gestation. Stored glycogen produces lung surfactant.
(vii) Energy storage: Glycogen production and storage takes place in the liver cells of animals. It acts as a stored energy reservoir secondary to the glucose cycle in the animal body. Dr. Siddiq Publications
(viii) Energy supply to the brain: A small amount of glycogen is stored in brain cells. It powers the conscious brain.

Glycogen is a complex polysaccharide. It is composed of numerous α-glucose molecules. In the process of glycogenesis, 30,000 molecules of glucose combine to form glycogen. Glucose molecules are linked by α-1-4 glycosidic bonds to form glycogen. Branching of glycogen occurs through α-1-6 linkage. Each branch contains 10-20 glucose molecules. Their molecular weight is 106-107 daltons. Glycogen is hydrolyzed into glucose. Glycogen is converted to glucose when needed to provide carbon and energy. For this reason, glycogen is called animal starch.

(i) Glycogen is a white powdery biochemical substance.
(ii) It is soluble in water. Dr. Siddiq Publications
(iii) It forms suspension in cold water.
(iv) Its molecular weight is 50 lakh daltons.
(v) On wet analysis it converts first to maltose and then to α-glucose.
(vi) It reacts with iodine solution to acquire a reddish violet color.
(vii) Heat removes its red color.
(viii) It reverts to black color on cooling.
(ix) Partially hydrolyzed to maltose and fully hydrolyzed to α-D glucose.
(x) It is converted into glucose in the process of glycolysis.
(xi) It keeps blood glucose levels normal.

Glycogen is a nutrient complex homopolysaccharide. Glycogen is the main stored food in the animal body. Glycogen is stored in the liver, muscles, brain and stomach of vertebrates. But the liver has the most. Human liver contains about 100-120 grams of glycogen. Cyanobacteria or blue-green algae and some fungi (yeasts) have glycogen as stored food. Glycogen is called animal starch. French scientist Claude Bernard (1857) discovered glycogen.

Glycogen is a nutrient complex homopolysaccharide. Glycogen is the main stored food in the animal body. Glycogen is stored in the liver, muscles, brain and stomach of vertebrates. But the liver has the most. Human liver contains about 100-120 grams of glycogen. Cyanobacteria or blue-green algae and some fungi (yeasts) have glycogen as stored food. Glycogen is called animal starch. French scientist Claude Bernard (1857) discovered glycogen.

Glycogen Properties/Religions
(i) Glycogen is a white powdery biochemical substance.
(ii) It is soluble in water. Dr. Siddiq Publications
(iii) It forms suspension in cold water.
(iv) Its molecular weight is 50 lakh daltons.
(v) On wet analysis it converts first to maltose and then to α-glucose.
(vi) It reacts with iodine solution to acquire a reddish violet color.
(vii) Heat removes its red color.
(viii) It reverts to black color on cooling.
(ix) Partially hydrolyzed to maltose and fully hydrolyzed to α-D glucose.
(x) It is converted into glucose in the process of glycolysis.
(xi) It keeps blood glucose levels normal.

Chemical structure of glycogen
Glycogen is a complex polysaccharide. It is composed of numerous α-glucose molecules. In the process of glycogenesis, 30,000 molecules of glucose combine to form glycogen. Glucose molecules are linked by α-1-4 glycosidic bonds to form glycogen. Branching of glycogen occurs through α-1-6 linkage. Each branch contains 10-20 glucose molecules. Their molecular weight is 106-107 daltons. Glycogen is hydrolyzed into glucose. Glycogen is converted to glucose when needed to provide carbon and energy. For this reason, glycogen is called animal starch.

Utilization of glycogen
(i) Stored food: Glycogen is stored in the animal body as stored food.
(ii) Glucose production: Glucose is produced from liver glycogen in the process of glycogenesis.
(iii) Muscle energy: Glycogen stored in skeletal and cardiac muscles provides extra energy to muscles.
(iv) Regulation of blood volume: It regulates blood volume in the body. Increases blood glucose levels by breaking down liver glycogen. Dr. Siddiq Publications
(v) Formation of suspension: It forms colloidal suspension in water.
(vi) Production of Surfactant: Glycogen begins to accumulate in the pulmonary cells of the fetal baby at 23 weeks of gestation. Stored glycogen produces lung surfactant.
(vii) Energy storage: Glycogen production and storage takes place in the liver cells of animals. It acts as a stored energy reservoir secondary to the glucose cycle in the animal body. Dr. Siddiq Publications
(viii) Energy supply to the brain: A small amount of glycogen is stored in brain cells. It powers the conscious brain.

(i) Stored food: Starch is stored in the plant body as stored food. Starch in plant seeds, fruits and tubers serves as stored food. Starch stored in rice, wheat, bhutra, cassava, corn and round potato is used as human food.
(ii) Source of energy: It acts as a source of energy in the organism. Starch is converted into glucose to provide energy and carbon molecules to the body. Dr. Siddiq Publications
(iii) Respiration: It generates heat and energy in respiration.
(iv) Research: Starch is used in the laboratory to produce glucose and alcohol.
(v) In Paper Industry: Starch is the main ingredient in paper industry.
(vi) Preparation of glue: Pure starch is mixed with hot water to make glue. It is used to make corrugated board glue.
(vii) In titration: Starch is used as indicator during titration.
(viii) Textile use: Warp seizing agent is produced from starch. Warp shrinking agents reduce the rate of yarn tearing during fabric weaving. Starch is used for beating (laundry) cloth. Dr. Siddiq Publications
(ix) Oil exploration: Starch is used to increase the viscosity of drilling fluids, which are slippery fluids in oil exploration.
(x) Manufacture of cosmetics: Starch is used in the manufacture of talcum powder and other cosmetics.
(xi) Food processing: Starch is used to increase the density of food during food processing.
(xii) Production of Polymers: Starch is used to make eco-friendly bioplastics and other synthetic polymers.
(xiii) Fuel production: Biofuel corn ethanol is produced from starch in a fermentation process.
(xiv) Reproduction: Starch stored in the fruits, seeds, rhizomes and corms of the plant participates in the production of offspring in the next season.
(xv) In pharmaceutical industry: Starch is used as active ingredient carrier, tablet disintegrant and binder in pharmaceutical industry.
(xvi) Clothing starch: Liquid clothing starch is prepared by mixing pure starch with water. It is used in garments and laundry.

Starch is a complex polysaccharide. Starch is made up of amylose and amylopectin. It contains 22% amylose and 78% amylopectin. Amylose is composed of 200-1000 molecules and amylopectin is composed of 2000-200,000 molecules of glucose. Numerous glucose molecules are linked by α-1-4 glycosidic bonds to form starch. However, glucose molecules can be joined by α-1-6 bonds. Starch is hydrolyzed to glucose.

(i) Starch is tasteless, odorless and colorless substance.
(ii) It is a white granular powdery organic chemical substance.
(iii) It is insoluble in water, alcohol and ether.
(iv) Starch turns blue in iodine solution.
(v) It breaks down at high temperature into large dextin particles.
(vi) Starch cannot oxidize Fehling’s solution.
(vii) Iodine reacts with amylose of starch to produce black or black-blue color.
(viii) Iodine reacts with amylopectin of starch to produce red or purple color.