Polymers and Monomers Quiz

Polymers and Monomers

• Monomers are single molecules that can join to form complex polymers.
• Polymers consist of many repeating monomer units and can be natural or synthetic.

Cellulose

• Most abundant organic molecule due to its presence in plant cell walls and slow decay.
• Made of unbranched chains of β-D-glucose units connected by β-1,4-glycosidic bonds.
• Insoluble in water; cannot be digested by humans due to inability to break down β-1,4-glycosidic bonds.

Types of Sugars (Carbohydrates)

• Monosaccharides: Single sugar molecules (e.g., Glucose, Fructose).
• Disaccharides: Two sugar molecules linked (e.g., Sucrose, Maltose).
• Polysaccharides: Long chains of monosaccharides (e.g., Cellulose, Starch).

Alpha vs Beta Glucose

• Alpha glucose: Hydroxyl groups on the same side.
• Beta glucose: Hydroxyl groups on opposite sides.

Formation and Structure of Cellulose

• Synthesized at plasma membrane and organized into microfibrils.
• Cellulose fibers are formed from combined microfibrils, each 5–12 mm wide and consisting of 20–40 chains.
• Contains at least 500 β-D-glucose units linked by β-1,4-glycosidic bonds.

Cellulose Reactions

• Cellulolysis: Degradation of cellulose via hydrolysis, microbial decomposition, and heat.
• Hydrolysis occurs primarily in acid-based solutions.

Intermediate Units from Cellulose

• Cellobiose: Two glucose molecules linked (e.g., Maltose).
• Cellotriose: Three glucose molecules linked.
• Cellotetraose: Four glucose molecules linked.

Enzymatic Breakdown of Cellulose

• Endocellulases: Break down the crystalline structure to amorphous strands.
• Exocellulases: Hydrolyze chain ends to produce smaller sugars like cellobiose and cellotetraose.
• β-glucosidases: Hydrolyze cellobiose and cellotetraose into glucose.

Cellulose Derivatives

• Acetate Compound: Derived from cellulose acetylation, allowing for solubility and versatility in applications like fiber production.
• Propionate Compound: A cellulose ester substituted with acetyl and propionyl groups, known for excellent solubility and stability.
• Butyrate Compound: A mixed ester with enhanced weather resistance and lower moisture absorption.
• Carboxymethyl cellulose (CMC): A water-soluble cellulose derivative used as a thickener in various industries.
• Ethyl Cellulose (EC): Used primarily as a coating material for paper and pills, as well as a thickener.

Extractives in Wood

• Enhance odor, permeability, durability, and luster of wood.
• Odor: Some woods emit pleasant scents due to extractives, useful in manufacturing specific products.
• Permeability: Extractives can block intercellular spaces, affecting fluid permeability.
• Durability: Increase wood density and resistance to moisture and destructive organisms.
• Luster: Can diminish wood's natural shine.

Tyloses

• Foam-like deposits found within vessels of certain wood species.
• Can block vessels, affecting wood uses; beneficial in whiskey barrel production in certain oak species.
• Influence seasoning and preservation processes.

Crystals in Wood

• Valuable for wood identification, commonly found in axial parenchyma and ray cells.
• Morphological changes in crystal-containing cells can aid in taxonomic classification.

Test your knowledge on polymers, monomers, and the different types of carbohydrates including cellulose. This quiz will cover key concepts such as monomer structures, carbohydrate classifications, and the differences between alpha and beta glucose. Perfect for students studying organic chemistry!