metabolism energy and life. metabolism the totality of an organisms chemical processes. catabolic...
DESCRIPTION
Complexity of Metabolism Bioenergetics – study of how organisms manage energyTRANSCRIPT
METABOLISM
ENERGY AND LIFE
METABOLISM
The totality of an organisms chemical processes.
CATABOLIC PATHWAYS
Degradative Processes
ANABOLIC PATHWAYS
Building Processes
Complexity ofComplexity of
MetabolismMetabolism
Bioenergetics – study of how organisms manage energy
THERMODYNAMICS
• 1ST Law of Thermodynamics – Energy can be tranferred or transformed, but it can be neither created or destroyed.
• 2nd Law of Thermodynamics – Every energy transfer or transformation increases the entropy (disorder or randomness) of the universe.
Organisms live at the expense of free energy
• Chemical reactions may be classified based on free-energy changes. They are either
– Exergonic – proceeds with a net release of free energy
– Endergonic – absorbs free energy from its surroundings to proceed
ATP Powers Cellular Work
• A cell does three main kinds of workMechanical - beating of cilia, muscle
contraction, chromosome movementTransport – crossing a membrane
against the concentration gradientChemical – building of polymers
What is ATP? The nitrogenous base adenine with a
chain of three phosphates groups attached to the ribose.
• When the terminal phosphate bond is broken, ATP becomes ADP. This is an exergonic reaction releasing 7.3kcal of energy per mole of ATP
The ATP Cycle
ENZYMES• Catalytic proteins• Substrate-specific • Lock and Key fit• Initiate chemical reactions without being
used in the reaction ( reused)• Named for their substrate usually and
have the suffix (-ase)
The Catalytic Cycle of an Enzyme
• Enzymes use a variety of mechanisms that lower activation energy and speed up a reaction.
• Enzymes allow reactions to take place at lower temperature ( body temperature).
Factors that affect enzyme activity• Temperature
– Up to a point, the velocity of the reaction increases with the increase in temperature
– Most enzymes function optimally around body temperature (between 35o-40oC)
– Above the optimal temperature, the hydrogen bonds of the enzyme disrupt and the enzyme is denatured
• pH– The optimal pH is between 6 and 8
Other Factors Affecting Enzyme Activity
• Cofactors – nonprotein helper– If it is organic, then
it is a coenzyme– Most vitamins are
coenzymes• Enzyme inhibitors
– Competitive site– Noncompetitive site