Energy – capacity to do work.

Work – occurs when a force moves matter (never 100% efficient)

A. Two forms:

1. kinetic – energy of movement.

2. potential – stored energy (can move).

B. Four types of energy – interrelated and convertible

1. Electromagnetic- energy travels by waves

- distance peak to valley is wavelength.

- frequency-waves per sec (hertz – Hz)

-radiation, microwave, X-ray, MRI, UV, IR, visible light

2. Electrical – interaction between charged particles

- movement of ions & e-

-volt-measure of potential energy generated by barrier separating pos/neg charges.

- physiology uses mV (=1/1000 V)

3. Chemical – potential energy in chemical bonds-catabolism (decomposition) large to small may release kinetic energy-anabolism (synthesis) consumes kinetic energy-exergonic vs endergonic

4. Thermal – random movement of atoms & molecules

- increased movement increases thermal energy

- Heat – energy passing from one substance to another

- Temp measures heat transfer capacity

- Measured in calories- heat energy required to raise 1ml (CC) water from 14.5 to 15.5oC.

- Kcal – 1000 calories

Two Categories of reactions

1. Exergonic (decomposition-catabolic) energy is released during the reaction (Rxn), reactants contain more energy than productes.

* glucose C6H12O6 + 6O2 6CO2 + 6H2O +

686 kcals

~ 40%of the energy converts ADP to ATP ~ 60% heat loss.

2. Endergonic – energy consumed, or put into the Rxn, products has more energy than reactants.

* Glucose + energy Lipids (stored in adipose for instance)

- some glucose is used for building blocks and some may be used to provide kinetic energy to power the Rxn.