Test: Carbohydrates - MCAT MCQ

Reducing sugars are carbohydrates that have a free aldehyde or ketone group, which can undergo oxidation reactions. Glucose is a reducing sugar because it has an aldehyde group at the C1 position. Fructose, sucrose, and maltose are non-reducing sugars because they lack a free aldehyde or ketone group.

Lactose is a disaccharide composed of one molecule of glucose and one molecule of galactose joined by a β-1,4-glycosidic bond. It is commonly found in milk and dairy products.

Starch is a storage polysaccharide found in plants. It is composed of glucose units joined by α-1,4-glycosidic bonds, with occasional α-1,6-glycosidic branch points. Starch serves as a source of energy for plants.

Aldose sugars are monosaccharides that contain an aldehyde group. Glucose is an aldose sugar, as it has an aldehyde group at the C1 position. Fructose, galactose, and ribose are ketose sugars, as they have a ketone group.

Cellulose is the most abundant carbohydrate on Earth. It is a structural polysaccharide found in the cell walls of plants. Cellulose is composed of glucose units joined by β-1,4-glycosidic bonds, which are not easily digested by humans.

Maltose is a reducing disaccharide composed of two glucose molecules joined by an α-1,4-glycosidic bond. It is a reducing sugar because it has a free aldehyde group at the C1 position of one of the glucose units.

Ribose is a pentose sugar and a common component of nucleic acids, such as RNA (ribonucleic acid). It is a monosaccharide with five carbon atoms and is involved in the formation of the sugar-phosphate backbone of RNA molecules.

Sucrose is a non-reducing disaccharide composed of one glucose molecule and one fructose molecule joined by an α-1,2-glycosidic bond. It does not have a free aldehyde or ketone group and, therefore, does not undergo oxidation reactions.

Glycogen is the energy storage polysaccharide in animals. It is composed of glucose units joined by α-1,4-glycosidic bonds, with α-1,6-glycosidic branch points. Glycogen is primarily stored in the liver and muscles and serves as a readily available source of glucose.

Chitin is a structural polysaccharide and a major component of the exoskeleton of arthropods, such as insects and crustaceans. It is also found in the cell walls of fungi. Chitin is composed of N-acetylglucosamine units joined by β-1,4-glycosidic bonds.