Cell Surface Carbohydrates Quiz

Cellular Recognition and Sugars

• Polysaccharides play a crucial role in displaying information to other cells through their structure.
• Glycolipids are lipids with covalently bonded carbohydrates, while glycoproteins are proteins linked to carbohydrates, usually short oligosaccharides.
• Glycolipids and glycoproteins are essential for cell-cell recognition and cell-substrate interactions.
• Blood type is determined by the type of oligosaccharides presented on the surface of blood cells.
• Different cell types in a multicellular organism display distinct sets of glycoproteins on their surface.

Structure and Function of Sugars

• Monosaccharides have a carbonyl group, which can be an aldehyde (aldose) or within the carbon chain.
• The presence of a carbonyl group and multiple polar hydroxyl groups makes sugars polar and hydrophilic.
• Sugars form hydrogen bonds with other molecules.
• The number of carbon atoms in monosaccharides varies, with examples including trioses (3 carbons) and pentoses (5 carbons, e.g., ribose).
• Spatial arrangements of monosaccharide atoms can differ, affecting their functions.

Formation of Ring Structures

• Sugars with 5 or more carbons rarely exist in linear form, instead forming ring structures in aqueous solutions.
• The carbonyl group bonds to a carbon with a hydroxyl group, forming a ring.
• The position of the newly formed C-1 hydroxyl group can be fixed in one of two possible orientations: below or above the plane of the ring.
• This leads to two possible forms of glucose: α-glucose and β-glucose, with β-glucose being more common due to its slightly greater stability.

Test your knowledge on cell surface carbohydrates, including the structure and function of polysaccharides, glycolipids, and glycoproteins. Identify how carbohydrates are attached to lipids and proteins in cells.