AP BIOLOGY

Detailed explanation-1: -In food and nutrition, energy is most often measured in kilocalories (kcal). One kilocalorie is the amount of heat required to raise the temperature of 1 kilogram (or 1 liter) of water, 1°C.

Detailed explanation-2: -Calories: (kilocalories) the units of heat that measure the energy used by the body and the energy that foods supply to the body.

Detailed explanation-3: -A calorie is a unit of energy that measures how much energy food provides to the body. The body needs calories to work as it should. Dietary fats are nutrients in food that the body uses to build cell membranes, nerve tissue (like the brain), and hormones.

Detailed explanation-4: -The kilocalorie, which has been defined as the amount of heat energy needed to raise the temperature of a kilogram of water 1° C., is the unit that has been used traditionally for expressing the energy value of foods.

Detailed explanation-5: -The SI-unit of heat-or energy-is joule (J). Other units used to quantify heat are the British Thermal Unit-Btu (the amount of heat to raise 1 lb of water by 1oF) and the Calorie (the amount of heat to raise 1 gram of water by 1oC (or 1 K)).