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