Energy Transformations Metabolism Energy Transformations

Metabolism The capacity to acquire & use energy to ensure survival. Cellular activities, Maintenance, Growth Building & Accumulating Breaking Apart & Eliminating Involves… ENERGY CHEMICAL REACTIONS

ENERGY The ability to do “work”…to cause change. Variety of forms: Light, Heat, Mechanical, Chemical, Electrical 2 Main States: POTENTIAL Stored energy, with the potential to do something. KINETIC Energy of motion; in the process of doing something.

Energy Transformations Potential Kinetic Potential Kinetic… Governed by Laws of Thermodynamics. 1st Law of Thermodynamics (Conservation of Energy) 2nd Law of Thermodynamics (Entropy)

1st Law of Thermodynamics Energy is neither created nor destroyed. The amount of energy in the universe is constant. BUT, energy can change FORMS SUN STARCH FOOD MOVEMENT COAL ELECTRIC HEAT

2nd Law of Thermodynamics Energy is generally transformed from HIGH QUALITY to LOW QUALITY forms. This leads to less and less organization. Entropy is a measure of disorganization. SUN STARCH FOOD MOVEMENT COAL ELECTRIC HEAT

Life has Organization Opposite of Entropy, but How? Why? Life requires a constant re-supply of high quality energy from…the sun.

Organization requires Energy Energy is stored (by living things) in chemical form…in chemical bonds. When bonds are broken, energy is often liberated. Chemical Reactions! Loss of energy… Gain of energy… EXERGONIC ENDERGONIC

Chemical Reactions Endergonic Exergonic Reversible Coupled A + B C C A + B A + B C E F + G A + B C

Metabolic Pathways SERIES of chemical reactions. Biosynthetic (Anabolic) = building pathways which consume energy. Degradative (Catabolic) = degrading pathways which release energy. Enzymes are responsible for each reaction. (we’ll come back to these later)

ATP Adenosine Triphosphate Energy Carrier – the energy currency

ATP Photosynthesis Cellular Respiration Sunlight Chemical Energy ATP -Chemical Energy Work

ATP Hydrolysis ATP ADP + Pi

ATP Drives other endergonic reactions: ATP ADP + Pi A + B C

ATP Regeneration of ATP = Phosphorylation.

ATP Phosphorylation ATP is “primed”. ? 1. Substrate-Level Phosphorylation. 2. Chemiosmotic Phosphorylation. ? ADP + Pi ATP

The CONTROLLERS of Energy Transformations Enzymes The CONTROLLERS of Energy Transformations http://tesladownunder.com/

Remember Metabolism… The capacity to acquire & use energy to ensure survival. Cellular activities, Maintenance, Growth Building & Accumulating Breaking Apart & Eliminating Involves… ENERGY CHEMICAL REACTIONS Controlled by ENZYMES

Enyzmes Proteins that catalyze chemical reactions Speed up reactions (“Catalysts”). Do not become part of the products. Enzymes act on substrates (the specific reactants for a chemical reaction) Enzymes are substrate-specific. There are many many enzymes!

Enyzmes Active Site – a region (or regions) where the substrate(s) fit.

Enyzmes Induced-fit model of enzyme activity. Enzyme induces the fit of substrates by bringing them into closer proximity & orientation.

Enyzmes Enzymes lower the Activation Energy for a particular chemical reaction.

Enyzmes Enzymes function best within certain Temperature & pH ranges.

Control of Enzymes Inducers - molecules that act as “ON” switches (Activators) Substrates Cofactors (non-protein portions of an enzyme) Metal ions (Fe++) Coenzymes (large organic cofactors) Vitamins NAD+ NADH Allow proper enzyme conformation, turning them “ON”.

Control of Enzymes Inhibitors (molecules that attach to enzymes, turning them “OFF”) Competitive Inhibitors Active Site inhibitors (“blockers”) Non-competitive Inhibitors Allosteric inhibitors Feedback Inhibition The product of a metabolic pathway inhibits an enzymes responsible for catalyzing a reaction earlier in the pathway.

Feedback Inhibition