Metabolism, Thermodynamics, and Enzymes: Key Concepts in Biology

Metabolism

the totality of an organisms chemical reactions that result from interactions between molecules within the cell

metabolic pathway

a sequence of chemical reactions undergone by a compound in a living organism, start with substrate end with product

catabolic pathway

breaking a complex molecule down into its simpler parts, releasing energy. i.e. cellular respiration

anabolic pathway

using energy to build complex molecules from simpler molecules. i.e. protein synthesis

Bioenergetics

the study of how organisms manage their energy resources

Energy

capacity to cause change, do work

kinetic energy

energy of motion

heat(thermal energy)

kinetic energy associated with random movement of molecules

potential energy

energy of position

chemical energy

potential energy available for release in a chemical reaction, energy within bonds

thermodynamics

study of energy transformations

closed system

isolated from surroundings, no energy transfer, can't work at equilibrium because its exhausted its ability to do work. free energy at a min

open system

not isolated, energy and matter can be transferred between system and surroundings, ie. Cells

1st law of thermodynamics

energy of the universe is constant, cannot be created or destroyed, can only be transferred or transformed, conservation of energy

2nd law of thermodynamics

during every energy transfer, some energy is unusable and often lost, every energy transfer or transformation increases the total entropy of the universe

Entropy

disorder, randomness

free energy

delta G, energy that can do work when temperature and pressure are constant, related to change in enthalpy(delta H), change in entropy(delta S) and temperature in Kelvin(T). delta G = delta H - T delta S

exergonic reaction

a reaction with a net release of free energy, negative free energy, spontaneous

endergonic reaction

a reaction that absorbs free energy from its surroundings, non-spontaneous, positive free energy

coupled reactions

the use of exergonic processes to drive endergonic ones, the energy given off from the exergonic is absorbed by the endergonic

ATP

adenosine triphosphate, composed of ribose (5 carbon sugar), adenine (nitrogenous base), and 3 phosphate groups. Phosphate tail can be broken through hydrolysis to produce energy, ADP, and an inorganic phosphate

Phosphorylation

how ATP drives endergonic reactions, covalently bonding a phosphate with another molecule, such as as reactant

Catalyst

a chemical agent that speeds up chemical reactions without being consumed by the reaction

Enzymes

a catalytic protein, speeds up metabolic reactions by lowering activation energy, very specific, reusable, unchanged by reaction

activation energy

initial energy needed to start a chemical reaction, free energy for activating reaction, given off by heat

induced fit

brings the chemical groups of the active site into positions that enhance their ability to catalyze the reaction, makes the enzyme more effective

cooperativity

another type of allosteric activation, binds to one active site but locks ALL active sites open, allowing products to be constantly produced