Heterotrophic organisms get the glucose from the food they consume. Calorie: a unit to measure the amount of energy in food. –1 Calorie = the amount of energy needed to raise the temperature of kilogram (or liter) of water 1 o C –1 calorie = the amount of energy needed to raise the temperature of gram (or milliliter) of water 1 o C –1 Calorie = 1,000 calories –Unit for measuring energy in food = Calorie Chemical Energy and Food

–Amylase: An enzyme that breaks down polysaccharides like glycogen and starch into glucose to begin cellular respiration. Carbohydrates, lipids and proteins can all be broken down to release energy. 1 Gram of Carbohydrates = 4 Calories –The bodies primary source of energy –Only a small amount of carbohydrates can be stored in the body. –Glycogen is a polysaccharide that is created to store glucose Chemical Energy and Food

1 Gram of Lipids = 9 Calories –The bodies secondary source of energy –Carbohydrates can be converted to lipids for storage. –Can body can store an unlimited amount of lipids. 1 Gram of Proteins = 4 Calories –Lipids and Proteins are broken down with processes other than cellular respiration. –Proteins in food are broken down into amino acids which are used as building material. –The body can break down proteins into energy as a last resort. Chemical Energy and Food