Energy, enzymes and reactions Flashcards
What is metabolism? What are the two amin types of metabolism?
All chemical reactions in a cell. It divides into catabolism (separation of molecules, hydrolysis, release of energy) and anabolism (formation of bonds, require energy input, condensation).
What is the second law of thermodynamics?
Energy spontaneously disperses from being localized if it is not hindered from doing so (entropy increases)
What is the condition for reactions to occur?
They can only happen if the energy is being dispersed into the universe (enttropy increase)
How can a cell release free energy?
By a chemical reaction that increases disorder in the cell, by a chmeical reaction that releases heat in the surroundings
Which types of reactions are always spontaneous?
Exergonic, catabolic
What explains the lipid bilayer formation?
The release of heat from the aggregation that cuases breaks in H-bonds drives the process of self-assembly due to the hydrophobicity of tehe pohopohlipids (release of heat diminishes the enthalpy).
What type of reactions are never spontaneous?
Heat is used and entropy decrease, most anabolic reactions require heat input
What is the only way anabolic reactions can occur?
By coupling them with a spontenous reaction to make the overall delta G negative.
What is the point of chemical equilibrium? Why is it always achieved?
In principle all reactions are reversible, so all reaction will reach chemicla equilibrium (no more net changes). At this point, delta G is euqal to 0
What effect does eactant concetration have on the Gibbs free energy?
Addition of reactant makes the delta G more negative as it drives the reaction forwards. Delta G is dynamic, cocnentrations mst be taken into consideration when studying chemical reactions
What is ATP used for? Why is it convenient? How is the delta G increased inside the cell?
Hydrolysis of ATP into ADP can be used to capture, transfer and store energy. The free energy released by exergonic reactions is captrure by ATP and can be used to drive endergonic reactions. THe increase in delta G is explained by the low quantity of ADP in the cells (constantly changed into ADP or AMP). Intermdiate between what we gain of energy and what we spend
Does the delta G indicate the rate of the reaction?
No
What is neccesary for endergoni reactions to occur? What is the name of this?
Extra energy added, activation energy of the reaction (energy needed to put molecules in trnasition state)
What is catalysis? Which reactions can be catalyzed?
Diminished activation energy, only reactions with negative delta G (as catalysis does not influence the delta G of the reaction)
What are the three main ways an enzyme acts?
Oreintation, charged environemnet, strain
