Biology 1408 Chapter 3

Why are biological macromolecules considered organic?

Biological macromolecules are organic because they contain carbon.

cellulose

polysaccharide that makes up the cell wall of plants; provides structural support to the cell

Describe the similarities and differences between glycogen and starch.

Glycogen and starch are polysaccharides. They are the storage form of glucose. Glycogen is stored in animals in the liver and in muscle cells, whereas starch is stored in the roots, seeds, and leaves of plants. Starch has two different forms, one unbranched (amylose) and one branched (amylopectin), whereas glycogen is a single type of a highly branched molecule.

What role do electrons play in dehydration synthesis and hydrolysis?

In a dehydration synthesis reaction, the hydrogen of one monomer combines with the hydroxyl group of another monomer, releasing a molecule of water. This creates an opening in the outer shells of atoms in the monomers, which can share electrons and form covalent bonds.

Why is it impossible for humans to digest food that contains cellulose?

The β 1-4 glycosidic linkage in cellulose cannot be broken down by human digestive enzymes. Herbivores such as cows, koalas, and buffalos are able to digest grass that is rich in cellulose and use it as a food source because bacteria and protists in their digestive systems, especially in the rumen, secrete the enzyme cellulase. Cellulases can break down cellulose into glucose monomers that can be used as an energy source by the animal.

during the breakdown of polymers, which of the following reactions takes place? a. hydrolysis b. dehydration c. condensation d. covalent bond

a. hydrolysis

dehydration synthesis

also, condensation; reaction that links monomer molecules together, releasing a molecule of water for each bond formed

plant cell walls contain which of the following in abundance a. starch b. cellulose c. glycogen d. lactose

b. cellulose

lactose is a disaccharide formed by the formation of a ________ bond between glucose and _______________ a. glycosidic; lactose b. glycosidic; galactose c. hydrogen; sucrose d. hydrogen; fructose

b. glycosidic; galactose

carbohydrate

biological macromolecule in which the ratio of carbon to hydrogen and to oxygen is 1:2:1 carbohydrates serve as energy sources and structural support in cells and form the a cellular exoskeleton of arthropods

dehydration synthesis leads to formation of a. monomers b. polymers c. water and polymers d. none of the above

c. water and polymers

polymer

chain of monomer residues that is linked by covalent bonds, polymerization is the process of polymer formation from monomers by condensation

an example of monosaccharide is a. fructose b. glucose c. galactose d. all of the above

d. all of the above

cellulose and starch are examples of a. monosaccharides b. disaccharides c. lipids d. polysaccharides

d. polysaccharides

biological macromolecule

large molecule necessary for life that is built from smaller organic molecules

polysaccharide

long chain of monosaccharides; may be branched or unbranched

hydrolysis

reaction causes breakdown of larger molecules into smaller molecules with the utilization of water

monosaccharide

single unit or monomer of carbohydrates

monomer

smallest unit of larger molecules called polymers

glycogen

storage carbohydrate in animals

starch

storage carbohydrate in plants

disaccharide

two sugar monomers that are linked together by a glycosidic bond

chitin

type of carbohydrate that forms the outer skeleton of all arthropods that include crustaceans and insects; it also forms the cell walls of fungi