Metabolism

Created by

Ansley Faivre

Cards (76)

metabolism 
the totality of an organism's chemical reactions, consisting of catabolic & anabolic pathways, which manage the material & energy resources of an organism
Metabolism is a property of life that comes from interactions between molecules
metabolic pathway 
a series of chemical reactions that either builds a complex molecule or breaks down a complex molecule into simpler compounds
Each pathway is catalyzed by a specific enzyme
catabolic pathway 
a metabolic pathway that releases energy by breaking down complex molecules into simpler compounds
anabolic pathway 
a metabolic pathway that consumes energy to synthesize a complex molecule from simpler compounds (sometimes called biosynthetic)
Catabolic pathway is called "downhill" (releases energy)
Anabolic pathway is called "uphill" (stores energy)
energy 
the capacity to cause change, especially to do work (move matter against an opposing force)
kinetic energy 
the energy associated w/ the relative motion of objects
potential energy 
the energy that matter possesses as a result of its location or spatial arrangement (structure)
chemical energy 
energy available in molecules for release in a chemical reaction; a form of potential energy
thermodynamics 
the study of energy transformations that occur in a collection of matter
isolated system 
unable to exchange either energy or matter w/ its surroundings (ex: liquid in a thermos)
open system 
energy & matter can be transferred between the system & its surroundings (ex: organisms absorb energy & release heat & metabolic waste products into the surroundings)
First Law of Thermodynamics 
the principle of conservation of energy; energy can be transferred & transformed, but it cannot be created or destroyed
entropy 
a measure of disorder, or randomness
The loss of usable energy during transfer or transformation causes the universe to become more disordered
Second Law of Thermodynamics 
the principle stating that every energy transfer or transformation increases the entropy of the universe
A spontaneous process can occur without any energy being invested (ex: water flows downhill)
A nonspontaneous process cannot occur on its own and it will only happen if energy is added to the system (ex: water will only move uphill if energy is added)
For a process to occur spontaneously, it must increase the entropy of the universe
free energy 
the portion of a biological system's energy that can perform work when temperature & pressure are uniform throughout the system
$\triangle H$  
change in system's enthalpy (equivalent to total energy)
$\triangle G=$ $\triangle H-T\triangle S$  
change in free energy
$\triangle S$  
change in system's entropy
$T$  
absolute temperature in Kelvin (K)
$\triangle G < 0$  
spontaneous
$\triangle G =$ $0$  
nonspontaneous
$\triangle G > 0$  
nonspontaneous
Every spontaneous process decreases the system's free energy
The more free energy, the less stable
Unstable systems (high G) tend to change so they become stable (lower G)
chemical equilibrium 
when chemical reactions get to a point where the forward & backward reactions occur @ the same rate
Free energy increases when a reaction is pushed away from equilibrium
A system at equilibrium cannot do work because it cannot spontaneously change
exergonic reaction 
a spontaneous chemical reaction in which there is a net release of energy
negative change in G
magnitude of change in G represents the amount of work the reaction can perform
endergonic reaction 
a nonspontaneous chemical reaction in which free energy is absorbed from the surroundings
positive change in G because this reaction stores free energy
change in G is the quantity of energy required to drive the reaction
3 Main Kinds of Work in Cells
Chemical work: the pushing of endergonic reactions
Transport work: pumping substances across membranes
Mechanical work
energy coupling 
in cellular metabolism, the use of energy released from an exergonic reaction to drive an endergonic reaction