Introduction: Lecture #1
The importance of the Sun, food, and ATP - Physiology of muscular work and exercise is a
matter of transforming bound energy into mechanical energy. First Energy from the sun is
trapped in green plants and conserved in the form of foodstuff. This food stuff is consumed by
us and is converted into a usable energy form know as ATP. This energy is utilized for various
biological activities and the rest is liberated as heat.
Bioenergetics - is the study of biological energy conversion.
Basic principles of energy conversion: Energy conversion reaction involve the coupling of an
endergonic and exergonic reaction. Energy given off of an exergonic reaction can be used to
power an endergoinic reaction.
• Endergonic - release energy ( produced Heat, ATP)
• Exergonic - Use energy (uses ATP)
• Example : coupled in body - production of ATP from 3 energy systems. This ATP gets
used to power our bodily functions.
ADP + Pi + energy > ATP - energy used to make a high energy molecule (endergonic) -
used in aerobic respiration when storing energy in ATP.
ATP > ADP +Pi +energy - energy released to help with cellular needs (exergonic) - used
How efficient can we be in our ability to directly use heat energy? Where does energy go?
• Some energy is lost in the form of heat. Eg shivering can generate heat (useless
contractions to get muscles warm).
• Exercise allows us to use Heat more efficiently.
• Q10effect - Where each 10 degrees increase in temperature doubles the reaction rate.
Once the muscle reaches optimal temperature it can perform reactions fast. Therefore
there is an increase in ATP production and power from the individual.
• Thus warm up is very beneficial:
1. Increases muscle temp - closer to optimal temp
2. Oxygen dissociates more readily with warmer muscle
3. Oxygen - Hemoglobin binding
• Efficiency of conversion = TOTALenergyconverted Carbohydrates
• Polysaccharides: Fibers, Starch
Fibers cannot be broken down by our enzymes - fruits, vegetables, nuts
Starch - pasta - potatoes
Sucrose, Lactose, Maltose
Glucose, Fructose, Galactose
• Tend to be even numbered about 16-22 carbons long
• Contain glycerol backbone, and 3 acyl groups.
• Unsaturated (double bonds) vs. Saturated (single bonds)
• Butter 4 carbon acyl group
• Creatine phosphate - used as energy source Creatine
• ATP- Adenosine-tri-phosphate
There is very little ATP sitting in muscle at rest, thus we need enzymes to re-
synthesize ATP. We are continually using ATP and making more.
• Creatine Phosphate:
2. Rapid reaction • Glycolysis:
2. Glucose - 2 pyruvate
3. fairly fast
4. No O2, Anaerobic
• Aerobic respiration/metabolism
2. Krebs cycle
3. Electron transport chain
4. 30-33 ATP
5. Use all substrates - CHO, FAT, A.A
6. Slowest process
• This reaction is very rapid and Runs out quickely (5-10 sec)
• Most creatine found in skeletal muscle
• 66% phosphorylated
• Good for rapid energy
• Doesn't produce lactic acid
• Uses two enzymes to Hydrolyze ATP from ADP and Pi: Creatine kinase,
• One involves the Creatine phosphate protein, and the other involves ADP.
• Decrease in CP and an increase in AMP seen during progressive intense
exercise has been studied as central players in the signaling of glucose entry into cells for, glycogenolysis and glycolysis - break down of glycogen and glucose to
ultimately produce more ATP the body to use as energy.
What limits these cycles?
• CP - Substrate can limit ATP, time (5-10sec), need fast ATP, recover in 8-10sec
• Glycolysis - limited by change in Ph, more H+ ions in cytoplasm, time (1min),
3/4 glycolysis, 20-25% Aerobic, CP all burned up, recover glycolysis in about
30-40 min, Depends on all