Question

Dominant sugar present in hemicelluloses is
1. Ribose
2. Ribulose
3. Xylulose
4. Xylose

Answer 1

Correct Answer - Option 4 : Xylose

Dominant sugar present in hemicelluloses is Xylose.

• Hemicelluloses are polysaccharides in plant cell walls that have beta-(1-->4)-linked backbones with an equatorial configuration.
• The most common hemicelluloses contain xylans (many molecules of the five-carbon sugar xylose linked together), a uronic acid (i.e., sugar acid), and arabinose (another five-carbon sugar).

• Xylose is a monosaccharide of the aldopentose type consisting of five carbon atoms and an aldehyde functional group.
• Xylose is a sugar isolated from wood.
• D-Xylose is a sugar widely used as a diabetic sweetener in food and beverage. 

• Ribose
  • ​Ribose also called D-ribose,
  • It is a five-carbon sugar found in RNA (ribonucleic acid), where it alternates with phosphate groups to form the “backbone” of the RNA polymer and binds to nitrogenous bases.
• Ribulose
  • ​Ribulose is a ketopentonase — a monosaccharide containing five carbon atoms, and including a ketone functional group.
  • Ribulose sugars are composed in the pentose phosphate pathway from arabinose. 
• Xylulose
  • ​Xylulose is a ketopentose, a monosaccharide containing five carbon atoms, and including a ketone functional group.
  • Xu5P is a metabolite in the pentose phosphate shunt pathway which increases with increased glucose metabolism and serves as a glucose signaling compound.