Post on 21-Dec-2015
Energy Transfer
ATP
“Energy Currency”
Potential energy in ATP used for all energy requiring processes of cells
Energy Transformation
Formation of ATP from food
Use of chemical energy in ATP for metabolic work
ATP Hydrolysis
ATP + H2O ADP + Pi – 7.3 kcal/molATPase
• Anaerobic Process – generates energy for immediate use
• Energy Liberating
Energy Currency
ATPADP + Pi
CHO, Lipids, and Proteins + O2
CO2 + H2O
PrecursorsSynthesized End Products
ATP
stored only in cells
total quantity 3.5 oz.
energy for few seconds
ATP Generation
ATP-CP system
glycolytic system
oxidative system
Creatine Phosphate
ATP ADP + P + EnergyEnergy
CP C + P + Energy
Biological Work
CK
ATPase
Creatine Phosphate
4 - 6x conc. of ATPEnergy released when C & P bond
brokenEnergy used to phosphorylate ADPUsed in activities < 15-20 sec.Anaerobic
Cellular Oxidation – Aerobic Metabolism
Cellular oxidation-reduction is the mechanism for energy metabolism
Electron Transport
Oxidative Phosphorylation
Electron Transport
Oxidation of hydrogen
Exergonic transport of electrons to oxygen electrons oxygen H2O
ADP is phophorylated (energized)
Electron Transport (Respiratory Chain)
NADH + H+
FADH2
Coenzyme Q
Coenzyme b
Coenzyme c
Coenzyme c1
Coenzyme aa3
H2O
ATP
ATP
ATP
NAD+
FAD
2H+
2e- ½ O2
2e-
2e-
2e-
2e-
2e-
Oxidative Phosphorylation
10 means for extracting & trapping energy (PO4)
>90% of ATP synthesis takes place in respiratory chain via oxidative reactions w/ phosphorylation
Oxidative Phosphorylation
ATP is synthesized when electrons transferred from NADH to O2
NADH + H+ + 3ADP +3P + ½ O2
NAD+ +H2O + 3ATP
Electron Transport-Oxidative Phosphorylation Efficiency
Oxidation of 1 mole of NADH 52 kcal
3 moles of ATP regenerated (3 moles * 7 kcal/mole = 21 kcal)
21/52 = 40% efficient
60% dissipates - body heat
Role of Energy Release from Food
Phosphorylate ADP ATP
Regeneration of ATP
Liver- amino acid- glycogen glucose
Adipocytes fatty acidsMitochondrionMuscle
- ATP, CP, triglycerides, glycogen, AA
Energy Release - CHO
Only macronutrient to generate ATP anaerobically
Light-moderate exercise provides ½ of energy
C6H12O6 + 6O2 6 CO2 + 6 H2O – 689 kcal/mol
Glycolysis - anaerobic
Glycolysis- glucose pyruvate (2)
Pyruvate lactic acid (2)
net gain 2 ATP 5% of total ATP generated in glucose breakdown (rapid)
Lactic Acid
If energy demands exceed O2 supply or
rate of H+ production exceeds usage
High intensity exercise LA in muscle blood (buffered) lactate energy metabolism
used during moderate exercise
Aerobic Metabolism
Kreb’s Cycle (2 ATP)
Electron Transport (2 ATP)
Oxidative Phosphorylation (32 ATP)
Lipid Catabolism
Greatest source of potential energy
90,000 - 110,000 kcal
Sources
Triglycerides stored in muscle
Triglycerides in lipoprotein complexes
FFA (triglyceride + 3 H2O glycerol + 3 FA)
UtilizationFA diffuse from adipocytes FFA
controlled by epi, norepi, glucagon, GH
Meal triglyceride synthesis
Moderate exercise FA utilization triglyceride breakdown
Energy Transfer - Lipid
18 carbon FA 146 ATP (438 ATP total) + 19 ATP (glycerol)
40% efficiency
30-80% of energy for biological work is provided by lipids
Energy Release - Protein
20 sustained exercise / intense training
AA (deaminated) carbon skeleton Kreb’s cycle
AA (deaminated ) pyruvate (gluconeogenesis)
Interrelationships
Kreb’s Cycle- link between food energy & chemical energy- provides intermediate substances mitochondria bionutrients for growth & maintenance
Interrelationships
Lipids more efficiently used in presence of CHO
lipid catabolism is dependent on oxaloacetate (Kreb’s - generated from pyruvate in CHO catabolism)
Interrelationships
Power output by lipids alone is only 1/2 that of when CHO is primary source
serve CHO depletion acetyl-CoA & FFA ketone bodies (ketosis)
Liver