Metabolism: Reactions and Energetics

metabolism

life-sustaining chemical transformations

chemical reactions

perform the work of the cell, about changes to sharing of electrons (rearrangements of bonds), arrows indicate forward or reverse

catabolic reactions

breaking down molecules, polymers --> monomers, entropy increases, enthalpy decreases, Gibbs Free Energy decreases

endergonic reactions

reaction that requires an input of energy

hydrolysis reactions

breaking down molecules requires water addition

reverse reactions

reactions related to the breaking down of macromolecules into their subunits: catabolic, endergonic, hydrolysis

anabolic reactions

building molecules, monomers --> polymers, entropy decreases, enthalpy increases, Gibbs Free Energy increases

exergonic reactions

reaction that releases energy

dehydration reactions

building molecules removes water from the organic molecule

forward reactions

reactions related to the combining of subunits to build macromolecules: anabolic, exergonic, dehydration

Gibbs Free Energy (G)

amount of energy in a system that is available to do work

Gibbs Free Energy (△G)

change in enthalpy - (temperature x change in entropy) OR △H - (T x △S)

enthalpy (H)

total internal energy of system, loosely held electrons have greatest energy, sharing of electrons in bonds form of potential energy, ______________ increased by creation of more complicated polymers (more bonds formed with lots of potential energy) --> increased by anabolic reactions, decreased by catabolic reactions

1st law of thermodynamics

energy can be converted from one form into another

entropy (S)

disorder of system, polymers are more organized than monomers --> increased by catabolic reactions, decreased by anabolic reactions

2nd law of thermodynamics

state of entropy increases over time

hydrophilicity

polar molecules and ions dissolve readily in water (ex: salt)

hydrophobicity

nonpolar molecules do not dissolve readily in water (ex: oil)

functional groups

group of atoms responsible for a molecule's properties (ex: hydroxyl, methyl, carbonyl, carboxyl, amino, phosphate, sulfhydryl)

organic molecules

carbon-based molecules, part hydrocarbons and part functional groups (which typically include oxygen, nitrogen, phosphorus, sulfur)

carbon

can form 4 covalent bonds —> can build lots of different shaped molecules