Carbohydrates: Monomers, Polymers, Disaccharides, and Polysaccharides

A set of Question-and-Answer flashcards covering monomers, polymers, disaccharides, and polysaccharides as described in the notes.

What is a monomer?

A monomer is a small building block that can join with other monomers to form a larger molecule.

What is a polymer?

A polymer is a long chain of monomers bonded together.

Name three monosaccharides.

Glucose, fructose, and galactose.

What is an isomer?

Two molecules with the same molecular formula but different structures.

Can glucose exist as alpha or beta forms, and what does this mean?

Yes; glucose can exist as alpha or beta anomers, differing in the orientation of the OH and H on the anomeric carbon.

What are disaccharides?

Two monosaccharides joined by a glycosidic bond; examples include sucrose, maltose, and lactose.

How are disaccharides formed?

By a condensation reaction that forms a glycosidic bond with the removal of water.

What happens during hydrolysis in carbohydrates?

Hydrolysis splits disaccharides into monosaccharides by adding water.

Provide formation equations for maltose, lactose, and sucrose.

Glucose + glucose → maltose + water; glucose + galactose → lactose + water; glucose + fructose → sucrose + water.

What are polysaccharides?

Polymers formed by condensation across many glucose monomers; main examples are starch, cellulose, and glycogen.

What glucose types do starch and glycogen use compared to cellulose?

Starch and glycogen use alpha-glucose; cellulose uses beta-glucose.

What bonds link monomers in starch and glycogen, and how do they cause branching?

Alpha-1,4 glycosidic bonds form the main chain; alpha-1,6 glycosidic bonds create branches (more frequent in glycogen).

What bonds link monomers in cellulose?

Beta-1,4 glycosidic bonds between beta-glucose monomers.

What are the roles of starch, cellulose, and glycogen?

Starch stores glucose in plants (amylose and amylopectin); cellulose provides structural strength to plant cell walls; glycogen stores glucose in animals (liver and muscle).

What is amylose?

A largely unbranched component of starch that forms a helical structure.

What is amylopectin?

A branched component of starch containing many alpha-1,6 glycosidic bonds.

How do cellulose chains differ from starch chains in structure and plant function?

Cellulose has long, unbranched beta-1,4 linked chains; forms strong, hydrogen-bonded networks in plant cell walls; starch has helical/branched alpha-1,4 (with alpha-1,6 branches in amylopectin) and stores glucose in plants.

Where is starch stored and what is its location in cells?

Stored in plant cells, especially in chloroplasts.

Where is cellulose located and what is its function in plants?

Located in plant cell walls; provides structural strength.

Where is glycogen stored and what is its structure like?

Stored in animal cells (liver and muscle); highly branched polymer with alpha-1,4 and more frequent alpha-1,6 bonds.

Are starch, glycogen, and cellulose soluble in water?

They are insoluble stores of glucose and do not significantly affect water potential.