BIO 315 CH 3

the study of the various types of energy transformations that occur in living organisms

• the capacity to do work, or the capacity to change or move something
• a) electrical energy can be transduced to mechanical energy when we plug in a clock
• b) chemical energy is converted to mechanical energy when heat is released during muscle contraction
• c) fireflies and luminous fish are able to convert chemical energy back to light

energy can neither be created nor destroyed, it can only change forms

• the change from one form of energy to another
• *photosynthesis is the most important energy ~ in the biological world; sunlight to chemical energy

expresses the concept that events in the universe have direction; they tend to proceed "downhill" from a state of higher energy to a state of lower energy

(delta) G - the maximum amount of energy that can be passed on for use in another process

• processes that can occur spontaneously, that is, processes that have a negative delta G
• favors the formation of products

• processes that are thermodynamically unfavorable, that is, they have a positive delta G (non spontaneous, you must put energy in)
• favors the formation of reactants

• are catalyst that speed up chemical reactions (accelerate bond-breaking/forming processes)
• are almost always proteins
• may be conjugated with nonprotein components

• inorganic enzyme conjugates (nonprotein components)
• most are metals - Zinc is important, also Iron, Magnesium

organic enzyme conjugates; Vitamins

• Are present in cells in small amounts
• Are not permanently altered during the course of a reaction (can participate repeatedly)
• Cannot affect the thermodynamics of reactions, only the rates
• Are highly specific for their particular reactants called substrates
• Produce only appropriate metabolic products
• Can be regulated to meet the needs of a cell

• reactants that are at the crest of the energy hump and ready to be converted to products are said to be at the ~
• few substrate molecules can reach this without an enzyme or catalyst
• compounds that resemble the ~ tend to be very effective inhibitors (they can bind tightly to the catalytic region of the enzyme