Metabolic pathway

Catabolic Pathway

(breakdown pathways)

some metabolic pathways release energy by breaking down complex molecules to simpler compounds.  

A major pathway of catabolism is cellular repiration.  Sugar glucose and other organic fuels are broken down in the presence of oxygen to carbon dioxide and water.  

Anabolic Pathways

(biosynthetic pathways)

comsume energy to build complicated molecules from simpler ones; 

ex: The synthesis of a protein from amino acids.  

catabolic and anabolic 

They are the "uphill" and "downhill" avenues of the metabolic map.  Energy released from the downhill reactions of a catabolic pathway can be stored and then used to drive the uphill reactions of anabolic pathways.  

Bioenergetics

The study of how energy flows through living organisms.

Energy 

The capacity to cause change.

Kinetic energy 

Energy can be associated with the relative motion of objects.  

ex: contraction of leg muscles moves the pedals.  

Heat or thermal energy 

is kenetic energy as associated with the random movement of atoms or molecules.  

Potential Energy 

Energy that is not kinetic; An object not presently moving may still possess energy.  

Chemical energy 

The potential energy available for release in a chemical reaction.  

ex; catabolic pathway; glucose.  

The laws of energy transformation

First law of thermodynamics-  the energy of the universe is constant.  Energy can be transferred and transformed but it cannot be created or destroyed. EX: electric co. do not make energy they just make it convenient for us.  

Second law-  every energy transfer or transf. increases the entropy of the universe.  Process to occur spantaneously it must increase the entropy of the universe.  during energy transfer or transformation some energy becomes unusable.  EX: charging your battery after time it wares out.

Thermodynamics 

The study of the energy transformation that occurs in a collection of matter.  

entropy

a measure of disorder, or randomness.  (loss of usable energy)

Spontaneous process

Instantaneous process 

Instantaneous (an explosion)

Spontaneous ( rusting of old car)

process that connot accour on its own is said to be nonspontaneous.  

Free energy (G)

is the portion of a system's energy that can perfom work when temp. and pressure are uniformed throughout the system.  

energy coupling

a key feature in the way cells manage their energy resources to do their work.  The use of an exergonic process to drive an endergonic one.  

a cell does three main kinds of work:

chemical work- the pushing of endergonic reactions, which

would not occur spontaneously.

Transport work- the pumping of substances across menbranes against the direction of spontaneous movement.  

mechanical work- the contractions of muscles cells, and the movement of chromosomes during cellular reproduction.  

ATP

contains the sugar ribose, wu\ith the nitrogenous base adenine and a chain of three phosphate groups bonded to it. ATP is also one of the mucleoside triphosphates used to make RNA.  

ATP can be broken down by hydrolysis

substrate

the reactant that an enzyme acts on.