topic 3

• the first law of thermodynamics: energy cannot be created nor destroyed but can be converted from one form to another
• potential energy: stored energy
• kinetic energy: energy of motion
• the second law of thermodynamics: disorder (entropy) in the universe, a closed system, continuously increases
• no energy transfer is 100% efficient, might lose some energy, some energy dissipates as heat
• entropy increases as free energy decreases
• dynamic equilibrium- rate of change is exactly the same in both directions
• exergonic reactions- spontaneous, releases energy, -G
• endergonic reactions- not spontaneous, +G
• input of free energy required to drive an endergonic reaction is supplied by an exergonic reaction
• ATP- adenosine triphosphate, energy source, formed by phosphorylation of ADP (endergonic)
• catabolism- breaking down big molecules into smaller ones (exergonic)
• anabolism- making big molecules from smaller ones (endergonic)
• phophocreatine- alternative energy compound, reversible reaction used to produce ATP when it's low
• ATP synthesis events include glycolysis, Krebs cycle, and oxidative phosphorylation
• glycolysis- 1 glucose molecule enters, 4 ATP are produced but 2 are consumed, 2 pyruvates are produced, it's an oxygen-independent process
• glycogenesis- generating glycogen
• glycogenolysis- breaking glycogen to make glucose
• glyconeogenesis- making glucose (sugar) in a new way with organic molecules, requires energy
• enzymes- mediators of metabolism, responsible for reactions in a cell
• enzymes lower the activation energy, speed up reactions and cannot change free energy
• competitive inhibition- inhibitor competes with the normal substrate for the active site of the enzyme
• noncompetitive inhibition- the inhibitor binds with the enzyme at a site other than the active site
• respiratory quotient- CO2 production/O2 consumption
• the larger the animal the lower the metabolic rate
• low RQ (respiratory quotient) = more energy stored in the food particle
• lipids> proteins> carbohydrates