Energy and Enzymes Flashcards
What is the function of cells
To break down and rebuild macromolecules
What is Metabolism
the chemical reactions inside cells
Catabolic pathway
Breaks bonds, releasing energy
- Using Kinetic energy (motion)
Anabolic
Bonds formed, stores potential energy
Thermodynamics 1st Law
“Energy can neither be created nor destroyed (conservation of energy)”
- But energy can change forms, transfer, flow
- Consequence of the 1st law: the total energy of a ‘closed’ system does not change
Thermodynamics 2nd Law (Entropy Rules)
- Energy transfer is not 100% efficient
- Entropy: (Disorder) Cannot be transformed into useful energy
-> Heat flows from high temp to low temp
-> Gas = most disordered state of water
-> Biological systems do Heat transfer = increase Entropy = Thermal Equilibrium
Free energy
Usable energy released from a chemical reaction avaible after accounting for entropy
Enthalpy
- Total heat content of a system
- The total energy of a system
Endergonic reactions
- When change in free energy > 0
- Products have more stored/potential energy than reactants
- Forming bonds that will store energy
- Non-spontaneous
Exergonic reactions
- When change in free energy < 0
- Reactants have more stored/potential energy than products
- Break bonds, releases energy
-> The kinetic energy performs work due to increased Entropy - Spontaneous
Activation Energy (EA)
- Energy input for endergonic/exergonic reactions
- Higher EA = slower reaction
- Endergonic = slowest reaction, requires most EA bc of energy barrier need to break bonds in reactants before forming new bonds
- EA comes from heat that produces high energy collisions
What does EA do for exergonic reactions
- When bonds break: Unstable High Energy Transition State - but EA overcomes this energy barrier
ATP
- Energy currency
- Adenine, a sugar, 3 phosphate groups forms the nulceic acid “ATP”
How does the free energy released in ATP hydrolysis work inside a cell?
It is immediately transferred to another molecule via an enzyme
Enzymes
- Use ATP to regulate and speed up reactions in cells
- Reduce EA bc they stabilize transition state
-> Do this by energy coupling, by first energying themselves - Enzymes don’t change free or potential energy of reactants or products
- They don’t create reactions