CARBOHYDRATES POLYSACCHARIDES Polysaccharides Many Sugars Formed when many

CARBOHYDRATES POLYSACCHARIDES

Polysaccharides • “Many Sugars” • Formed when many mono or disaccharides form together by dehydration condensation • Made up of a long chain of simple sugars • Ex: cellulose, starch, glycogen • These are all polymers of glucose, meaning, these are many glucose molecules bonded together

Cellulose • Glucose molecules arranged in chains, linked by hydrogen bonds • Cellulose is a sheet of fiber and will not dissolve in water due to the H-bonds holding it together • Makes up the plant walls • 50% of organic matter is made of cellulose

Cellulose • People can not digest it, serves as fiber that keeps things moving in the digestive track • Some micro-organisms that can dissolve cellulose are in the stomachs of some animals (cows, for example) • Cows and other herbivores (plant eaters)have extra stomachs that hold the grasses for a long time so the microorganisms can break down the cellulose in the grasses that they eat

Starch • Storage form of glucose in plants • From foods such as potatoes and cereal grains • 66% of the food eaten by people around the world is in the form of starch • Broken down into glucose during digestion

Carbohydrates Reactions • There are two types of reactions that carbohydrates go through • Dehydration condensation – “Water forming” • Hydrolysis – “Water splitting”

Dehydration Condensation • Reaction in which two molecules or parts of the same molecule combine, also forming a molecule of water. • Ex: Glucose + Fructose = ? (look in Thursday notes) • Glucose & fructose bond through dehydration condensation, (just like amino acids). • A water molecule forms, and the two monosaccharides bond together.

Hydrolysis • Disaccharides and polysaccharides can be broken down into smaller simple sugars via hydrolysis • A chemical reaction using water to break bonds (add water) to form two or more new substances • Occurs in many common processes • Ex: making jam and jellies • Cook sucrose (table sugar) with acids (berries) causes it to break down into a mixture of equal parts of glucose and fructose