Food Chemistry
What three macronutrients can provide energy to the body?
Carbohydrates, fats, and proteins.
What is a calorie?
A unit used to measure energy.
What is a macronutrient?
A nutrient needed by the body in relatively large amounts.
A food has 10 g of carbohydrates. How many kcal does it provide?
40 kcal
What unit is commonly used to measure the energy in food?
Calories
What type of bonds hold the atoms together in most food molecules?
Covalent bonds.
How many calories are in 1 kilocalorie (kcal)?
1,000 calories.
What is a kilocalorie (kcal)?
1,000 calories; it is the unit used for food energy.
A food has 5 g of fat and 10 g of protein. How many kcal does it provide?
85 kcal.
What is the difference between a calorie (cal) and a kilocalorie (kcal)?
1 kilocalorie equals 1,000 calories.
What is the chemical energy in food associated with?
Structure and bonding of food molecules.
How many kilojoules (kJ) are in 1 kilocalorie?
4.184 kJ.
What is a covalent bond?
A bond where atoms share electrons.
A snack has 20 g carbs, 5 g protein, and 4 g fat. How many total kcal?
136 kcal.
What is the difference between a calorie and a kilojoule?
They are both units used to measure energy, but they use different scales.
Why can different food molecules provide different amounts of energy?
because they provide more grams of calories and can release more energy when being metabolized
A food contains 250 kcal. How many kilojoules is that?
(remember 4.184kJ!)
1,046 kJ.
250 x 4.184
What is chemical potential energy?
Energy associated with the structure and bonding of a substance.
Which provides more energy: 10 g of fat or 20 g of carbohydrates? How much more?
10 g of fat provides more.
A food contains 300 kcal. How many kJ of energy does it contain?
About 1,255 kJ.
How do chemical reactions allow the energy in food molecules to become usable by the body?
Chemical reactions break down and transform food molecules, allowing their chemical potential energy to be transferred into forms the body can use.
A food contains 1,500 kJ of energy. About how many kilocalories is that?
359 kcal.
What does metabolism mean?
The chemical reactions in the body that transform nutrients and energy.
A meal contains 30 g carbs, 15 g protein, and 10 g fat. What percentage of its total energy comes from fat?
~33%.
A food label says the food contains 2,000 kJ of energy. About how many kcal is that?
About 478 kcal.