Lecture 5: The Molecules Of Life Flashcards
Enzymes
Specialized macromolecules that speed up chemical reactions
Dehydration reaction
2 monomers bond together through loss of a water molecule
Hydrolysis
Polymers disassembled to monomers through addition of a water molecule
Hydrogen from water attaching to one monomer and hydroxyl group attaching to other
Monosaccharides
Simple sugar
Disaccharide
Consists of 2 monosaccharides joined by a glycosidic linkage
Covalent bond formed between 2 monosaccharides by a dehydration reaction
Polysaccharides
Polymers of many sugars joined by glycosidic linkages via dehydration synthesis
Ex. Starch, glycogen, cellulose
Starch
Storage form of glucose in plants
Glycogen
Storage form of glucose in animals
Cellulose
Contribute fiber
Like starch, cellulose is a polymer of glucose, but glycosidic linkages differ
The difference between starch and cellulose is based on
2 ring forms for glucose: alpha(α) and beta (β)
Starch is alpha configured and is largely helical
Cellulose molecules are beta configured and straight and unbranched
Enzymes that digest starch by hydrolyzing alpha linkages
Can’t hydrolyze beta linkages in cellulose
Cellulose in human food passes through the digestive tract as
“Insoluble fiber”
Fats
Constructed from 2 types of smaller molecules: glycerol and fatty acids
Glycerol is
3 carbon alcohol with a hydroxyl group attached to each carbon
Fatty acid is
One Carboxyl group attached to a long carbon skeleton
Fats separate from water because
Water molecules hydrogen-bond to each other exclude fats
Nonpolar C-H bonds in hydrocarbon chains of acids are
Hydrophobic
Saturated fatty acids
No double bonds between C atoms of chain
Allows fat molecules to pack together tightly (butter- solid at room temperature)