Thermodynamics and Metabolsim- Chapter 6 Flashcards
Thermodynamics
A branch of chemistry and physics focused on energy changes.
Energy
The capacity to do work, existing in two states.
Kinetic Energy
Energy of motion
Potential Energy
Stored energy
Forms of energy
Mechanical, heat, sound, electric current, light, or radioactivity.
1 calorie
Heat required to raise 1 gram of water by 1ºC.
1 Calorie
1,000 calories = 1 kcal.
1 calorie in joules
1 calorie = 4.2 joules (or 1 joule = 0.239 calories).
Energy flow from the sun
13 \times 10^{24} calories per year or 40 million billion calories per second.
Energy equivalent
The sun produces enough energy every second equivalent to about a trillion 1 megaton bombs.
Energy for civilization
In one second, the sun generates enough energy for nearly 500,000 years of current civilization needs.
Photosynthetic energy capture
98.8 kcal to break one mole (6.023 \times 10^{23}) of carbon-hydrogen (C-H) bonds in organic molecules.
Oxidation
An atom or molecule loses an electron.
Reduction
An atom or molecule gains an electron, resulting in a higher energy level than the oxidized form.
Redox Reactions
Always paired, summarized by the acronym OIL RIG (Oxidation Is Loss, Reduction Is Gain).
First Law of Thermodynamics
Energy cannot be created or destroyed, only transformed. The total energy in the universe remains constant, but some energy is lost as heat during conversions.
Second Law of Thermodynamics
Entropy (disorder) is continuously increasing. Energy transformations tend to convert matter from a more ordered/less stable form to a less ordered/more stable form.
Free energy
The amount of energy available to break and form bonds.
Gibbs free energy formula
G = H - TS
Enthalpy (H)
Energy in a molecule’s chemical bonds.
Absolute Temp (T)
K = °C + 273.
Entropy (S)
Unavailable energy.
Charge in Free Energy
Delta G = Delta H - TS
Positive ΔG
Products have more free energy than reactants (not spontaneous, requires energy input - Endergonic).
Negative ΔG
Products have less free energy than reactants (spontaneous - Exergonic).
Endergonic
Requires energy input
Exergonic
Releases energy
Activation energy
Extra energy needed to destabilize existing bonds and start a reaction.
Catalysts
Substances that lower activation energy without violating thermodynamic laws.
ATP (Adenosine Triphosphate)
The chief energy currency of all cells.
ATP composition
Composed of Ribose (5 carbon sugar), Adenine, Chain of 3 phosphates.
ATP → ADP energy release
Releases 7.3 kcal/mol.
ATP → AMP energy release
Releases 10.3 kcal/mol.
ATP hydrolysis
Drives endergonic reactions, resulting in a net negative ΔG (exergonic and spontaneous).
Long-term energy storage
ATP is not suitable for long-term energy storage; fats and carbohydrates are better.
Enzymes
Most are proteins; some are RNA.
Enzyme function
Stabilize temporary associations between substrates.
Carbonic anhydrase example
Can produce 600,000 molecules of carbonic acid per second with the enzyme, compared to 200 without it.
