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Flashcards in Energy Balance Deck (113)
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1

Summarise catabolism/anabolism

  • Oxidation of carbohydrates, proteins + fats
    • Energy + CO2 + H2O produced

2

Catabolism

  • The reaction of energy supplying oxidation
  • Releasing utilisable energy

3

Anabolism

  • Synthesis of proteins, fats and carbohydrates from small molecules
  • This required energy

4

Released energy can be utilised as...

  • Heat
  • Energy
  • Work
    • Internal work
    • External work

5

Internal work

  • Chemical
  • Electric
  • Osmotic

6

External work

Mechanical work

7

Define 1 calorie

The energy required to raise the temperature of 1g water by 1°C

8

1 calorie = ? J

4.184 J

9

Which materials aren't entirely combusted in the body?

Proteins

10

The heat content of nutrients can be measured in a...

Bomb calorimeter

11

The heat measured with a bomb calorimeter gives...

The maximum heat/energy that can be yielded from a particular nutrient in the body

12

Compare oxidation in the bomb calorimeter and in the animal body

Calorimeter:

  • Fast combustion
  • High temp.
  • Gaseous phase

In the body:

  • Slow, Gradual combustion
  • Low temperature
  • Liquid phase

13

Law of Hess related to energy combustion in the body

  • As long as the final products are the same
  • Energy released during oxidation = Energy in

14

  • 17kJ/g
  • 17kJ/g

15

  • 39kJ/g
  • 39kJ/g

16

  • 22kJ/g
  • 17 kJ/g

Physical heat equivalent > Physiological caloric value

 

17

14.6kJ/g

18

20.8 kJ/g

19

24 kJ/g

20

Why is protein combustion heat higher than its physiological caloric value?

  • Incompleteness of protein combustion
  • Urea is an additional product which has a relatively high combustion heat

21

Gross energy (GE)

  • Total energy of nutrients
  • Consumed by the animal
  • Measured in a bomb calorimeter

22

Digestible energy (DE)

Energy absorbed that doesn't leave the body as faeces

23

% energy is lost through...

  • Faeces: 10%-60%
  • Urine: 3-5%
  • Methan: 5%

 

24

Energy lost with 1 mol of urea

634 kJ

25

1 mol of uric acid contains...kJ energy

1925 kJ

26

Digestible energy - energy in the urine =

Metabolisable energy

27

Net energy (NE)

The difference between:

  • Metabolised energy
  • Energy emitted from the body as heat

28

Energy balance of the body is assessed by measuring...

Heat turnover

29

Basal metabolic rate (BMR)

  • Energy production measured in an individual
  • In a complete resting state

30

Give the requirements of BMR measurement

  • Complete rest
  • Lying posture
  • No psychic excitement
  • Neutral environmental temperature