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