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 1oC

– 1 calorie = the amount of energy needed to raise the temperature of gram (or milliliter) of water 1oC

– 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