Biochemistry Monosaccharides Quiz

Carbohydrates

• Carbohydrates are one of the three macronutrients, providing the body with energy.
• Their chemical formula follows the general pattern (CH₂O)ₙ.
• Categorized into monosaccharides, disaccharides, and polysaccharides.

Monosaccharides

• These are the simplest carbohydrates, also known as simple sugars.
• They serve as building blocks for more complex carbohydrates.
• Examples include glyceraldehyde and dihydroxyacetone, both trioses.
• Classified as aldoses or ketoses based on the presence of an aldehyde or ketone group.
• Further classified based on the number of carbon atoms: trioses, pentoses, and hexoses, with corresponding names (e.g., aldohexose = glucose).
• Illustrate monosaccharides using Fischer or Haworth formulas, often representing the cyclical forms found in nature.
• Demonstrate structural differences and isomers (enantiomers, diastereomers, epimers, and anomers), which are crucial for their biological function.

Stereoisomers

• Isomers are molecules with the same molecular formula but different structural arrangements.
• Stereoisomers have the same molecular formula and constitution but differ in spatial orientation.
• Stereoisomers are classified into enantiomers, diastereomers, epimers, and anomers.
  • Enantiomers are mirror images of each other.
  • Diastereomers are not mirror images and differ in the configuration around at least one chiral carbon.
  • Epimers are diastereomers differing in configuration at only one chiral carbon.
  • Anomers are stereoisomers that differ in configuration only around the anomeric carbon (the carbon atom that was part of the carbonyl group in the open-chain form).

Disaccharides

• These are composed of two monosaccharide units joined by a glycosidic linkage.
• Common examples include:
  • Sucrose (common table sugar),
  • Maltose (product of starch hydrolysis),
  • Trehalose (found in fungi),
  • Lactose (main sugar in milk), and
  • Melibiose (found in legumes).

Polysaccharides

• Complex carbohydrates composed of multiple monosaccharide units.
• Functions include storage (starch and glycogen) and structural components (cellulose, chitin, etc.).
  • Starch is a storage polysaccharide in plants, consisting of amylose (linear) and amylopectin (branched) forms.
  • Glycogen is the storage polysaccharide in animals.
  • Cellulose is a structural polysaccharide in plant cell walls with a strong structure, difficult to digest.

Additional Concepts

• Glycosidic linkage—bond formed between monosaccharides to create disaccharides or polysaccharides.
• Oligosaccharide - chains of a small number of monosaccharides
• Glycosaminoglycans - components of connective tissue, important in vertebrate animals.