Week 2&3: Cellular energy
Nutritional energy and role of ATP
Uses of different energy sources
Energy classification
GE → Bomb calorimeter
DE → 98% for CHO, 95% for fat, 93% for protein
ME → 4 kcal/g for carbohydrates, 4 kcal/g protein, 9 kcal/g lipid
Gross energy Metabolisable energy
Amylose > maltose > glucose > cellulose
Cellulose is not digestible so ME = 0
MW=180 g/mol MW=2*180-18=342 g/mol
GE glucose = 2816 kJ/mol = 15.6 kJ/gram
GE maltose = 2*2816 kJ/mol = 5632 kJ/mol
= 16,5 kJ/gram
Energy per mol is the same per unit, but
molecular weight is lower because of
condensation
Cellulose = amylose > maltose > glucose
,Energy needed for:
- Mechanical work
- Electrical work
- Chemical work
Production of ATP
Direct : Substrate phosphorylation (anaerobic) Indirect :
Oxidative phosphorylation (aerobic)
ATP : ADP ratio in cell 500 : 1
Usage of intracellular ATP
1. Endothermic (metabolic) reactions
2. Linked to H + gradient, and cellular transporters
3. ABC transporter = ATP-binding cassette transporters
P-type transporters have to be phosphorylated to allow transport
Dephosphorylated again due to transport of substrate
4. Metabolic trapping
Glucose is absorbed and phosphorylated
P inhibits the transport over the cell membrane
5. Protein regulation by phosphorylation
Creatine
Storage of energy reserves
, Nomenclature
Pyruvic acid → Pyruvate
Acetic acid → Acetate
Lactic acid → Lactate
α-keto-glutaric acid → α-ketoglutarate
Oxidation of glucose
GE = 2816 kJ
30 mol ATP (33 kJ/mol)
30 × 33 = 990 kJ trapped in ATP
Efficiency: 35% [(990/2,816) × 100%]
2816 – 990 = 1826 kJ released as heat
Nutritional energy and role of ATP
Uses of different energy sources
Energy classification
GE → Bomb calorimeter
DE → 98% for CHO, 95% for fat, 93% for protein
ME → 4 kcal/g for carbohydrates, 4 kcal/g protein, 9 kcal/g lipid
Gross energy Metabolisable energy
Amylose > maltose > glucose > cellulose
Cellulose is not digestible so ME = 0
MW=180 g/mol MW=2*180-18=342 g/mol
GE glucose = 2816 kJ/mol = 15.6 kJ/gram
GE maltose = 2*2816 kJ/mol = 5632 kJ/mol
= 16,5 kJ/gram
Energy per mol is the same per unit, but
molecular weight is lower because of
condensation
Cellulose = amylose > maltose > glucose
,Energy needed for:
- Mechanical work
- Electrical work
- Chemical work
Production of ATP
Direct : Substrate phosphorylation (anaerobic) Indirect :
Oxidative phosphorylation (aerobic)
ATP : ADP ratio in cell 500 : 1
Usage of intracellular ATP
1. Endothermic (metabolic) reactions
2. Linked to H + gradient, and cellular transporters
3. ABC transporter = ATP-binding cassette transporters
P-type transporters have to be phosphorylated to allow transport
Dephosphorylated again due to transport of substrate
4. Metabolic trapping
Glucose is absorbed and phosphorylated
P inhibits the transport over the cell membrane
5. Protein regulation by phosphorylation
Creatine
Storage of energy reserves
, Nomenclature
Pyruvic acid → Pyruvate
Acetic acid → Acetate
Lactic acid → Lactate
α-keto-glutaric acid → α-ketoglutarate
Oxidation of glucose
GE = 2816 kJ
30 mol ATP (33 kJ/mol)
30 × 33 = 990 kJ trapped in ATP
Efficiency: 35% [(990/2,816) × 100%]
2816 – 990 = 1826 kJ released as heat
