Quiz On Carbohydrates Biochemistry

Cellulose is the major constituent of plant cell walls. It is a complex carbohydrate made up of long chains of glucose molecules. Cellulose provides structural support to plant cells, making them rigid and allowing them to maintain their shape. It also forms a barrier that protects the cell from external threats. Glycogen, chitin, and starch are not major constituents of plant cell walls. Glycogen is the main storage form of glucose in animals, chitin is found in the exoskeleton of arthropods, and starch is the main storage form of glucose in plants.

Glycogen is the storage form of carbohydrate in animals. It is a complex molecule made up of glucose units that are linked together. Animals store glycogen primarily in their liver and muscles. When energy is needed, glycogen is broken down into glucose to provide fuel for the body. Unlike starch, which is the storage form of carbohydrate in plants, glycogen is more highly branched, allowing for quick and efficient release of glucose when needed. Cellulose and chitin are structural carbohydrates found in the cell walls of plants and the exoskeletons of arthropods, respectively.

Chitin forms the exoskeleton of anthropods. Chitin is a tough and flexible polysaccharide that provides structural support and protection to the bodies of anthropods such as insects, crustaceans, and arachnids. It is a key component of their exoskeleton, which acts as a protective outer covering. Chitin is a strong material that allows anthropods to maintain their shape and withstand physical stress. It is not agarose, cellulose, or starch that forms the exoskeleton, but chitin.

Benedict's test is used to identify reducing sugars and was historically used to test for diabetes mellitus. This test involves the reaction of reducing sugars with Benedict's reagent, which contains copper sulfate. The reducing sugars reduce the copper ions in the reagent, resulting in the formation of a colored precipitate. This test is no longer commonly used for diagnosing diabetes mellitus, but it is still used in various laboratory settings to detect the presence of reducing sugars.

Glycogen is a form of glucose storage in the body. It is primarily stored in the liver and muscles. The liver stores glycogen to maintain blood glucose levels and provide energy to the body when needed. The muscles store glycogen to provide energy for muscle contractions during physical activity. Therefore, the correct answer is "in the muscle and liver."

Agarose is used in the laboratory for DNA electrophoresis. Agarose is a polysaccharide derived from seaweed and is commonly used as a gel matrix for separating DNA fragments based on their size during electrophoresis. It forms a porous gel structure that allows the DNA molecules to migrate through it when an electric current is applied. Agarose is preferred over other options like cellulose, chitin, and glycogen due to its low cost, ease of use, and ability to provide good resolution for DNA fragments of different sizes.

Starch is the storage form of carbohydrate in plants. It is a polysaccharide made up of glucose molecules and is stored in plant cells as granules. Starch serves as a reserve energy source for plants and can be broken down into glucose when needed for growth, development, or reproduction. It is commonly found in roots, tubers, and seeds of plants.

Amylose is a type of starch that is composed of unbranched linear chains of glucose molecules. These glucose molecules are linked together through alpha 1-4 glycosidic linkages. This means that the glucose molecules are connected by a bond between the first carbon of one glucose molecule and the fourth carbon of the next glucose molecule. This linear structure allows amylose to form a helical shape, making it compact and insoluble in water.

Amylopectin is a highly branched polymer with branched sites containing alpha 1-6 glycosidic linkages. This means that it has a main chain made up of glucose units linked by alpha 1-4 glycosidic linkages, with branches occurring at alpha 1-6 glycosidic linkages. These branches give amylopectin its highly branched structure, allowing for more efficient storage of glucose molecules and easier access for enzymes involved in its metabolism.

Glucose, mannose, and galactose are all monosaccharides that have the same molecular formula (C6H12O6) but differ in the arrangement of their hydroxyl groups. Specifically, glucose and mannose differ in the configuration of the hydroxyl group at carbon 2, while glucose and galactose differ in the configuration of the hydroxyl group at carbon 4. This makes glucose, mannose, and galactose epimers, which are a type of stereoisomer that differ in the configuration of only one chiral center.