Energy in food

Question 1

what happens when fuels are used or food is digested

Answer 1

the chemical energy is converted into a different form of energy (energy transformation)

Question 2

what changes and what doesn’t when energy transformations occur

Answer 2

the total amount of energy remains unchanged as energy cannot be created or destroyed but not all the energy is converted into one form

Question 3

energy transformation efficiency

Answer 3

the percentage of energy from a source that is converted to useful energy

Question 4

percentage energy effiency equation

Answer 4

% energy efficency = useful energy/energy input x 100

Question 5

why is the energy released when food is burned greater than the energy that is avliable for the body to use after is has been digested

Answer 5

incomplete absorption of nutrients by the body after digestion of food, incomplete oxidation of nutrients, heat loss

Question 6

why does cellulose not have a high energy food content

Answer 6

because humans lack the nezyme cellulase which is required to break down cellulose so that energy can be obtained

Question 7

carbs energy content combustion (KG g-1)

Answer 7

16

Question 8

fats and oils energy content combustion (KG g-1)

Answer 8

39

Question 9

proteins energy content combustion (KG g-1)

Answer 9

24

Question 10

energy value to body (KG g-1) ofcarbs

Answer 10

16

Question 11

energy value to body (KG g-1) of fats and oils

Answer 11

37

Question 12

energy value to body (KG g-1) of proteins

Answer 12

17

Question 13

equation to calculate energy value of food

Answer 13

energy value of food = (% carbs x 16) + (% proteins x 17) + (% fats x 37) x 100