Chapter 6 Ap Bio
Energy and Metabolism
Chapter 6
Energy and Metabolism
• Organisms require the constant input of free energy and matter for growth, reproduction, and maintenance of living systems • Life requires a highly ordered system
▫ What is free energy?
Energy available to do work in any system G
What other types of energies do cells use?
• Potential
▫ Stored energy ▫ Chemical
• Kinetic
▫ Energy of motion
Thermal Energy
• • • • All forms of energy can be converted to heat Thermodynamics – “study of heat changes” Actually a type of kinetic energy Enthalpy (H): Heat content
How cells use energy
• Excess acquired free energy versus required free energy results in energy storage or growth • Changes in free energy disruptions • Coupled reactions • Chemical work • Electrochemical work • Mechanical work
Coupled Reactions
• Use of an exergonic process to drive an endergonic one ▫ Photosynthesis and respiration ▫ ATP/ADP Cycle
Chemical Work
• Build, rearrange, break apart substances
▫ Polymers from monomers
Electrochemical Work
• Transport – Pumping of substances • Moving charged particles across membranes
Mechanical Work
• Physical Movement
▫ Muscles ▫ Flagella
Metabolic Reactions
• According to the laws of thermodynamics, biochemical reactions may change the form of energy but not the net amount
First Law of Thermodynamics
• Energy cannot be created nor destroyed • Total amount of energy in the universe remains constant
▫ Energy dissipates as heat replenished by sun ▫ Heat = measure of random molecules
Second Law of Thermodynamics
• Energy flows from usable to unusable forms • Disorder in the universe is continuously increasing
▫ Less order = more stable ▫ Entropy = measure of disorder
Entropy Happens!
Second law cont.
• Organisms do not violate the 2nd law • Order is maintained by coupling cellular processes that increase entropy (negative changes in free energy) to those that decrease entropy
Chapter 6
Energy and Metabolism
• Organisms require the constant input of free energy and matter for growth, reproduction, and maintenance of living systems • Life requires a highly ordered system
▫ What is free energy?
Energy available to do work in any system G
What other types of energies do cells use?
• Potential
▫ Stored energy ▫ Chemical
• Kinetic
▫ Energy of motion
Thermal Energy
• • • • All forms of energy can be converted to heat Thermodynamics – “study of heat changes” Actually a type of kinetic energy Enthalpy (H): Heat content
How cells use energy
• Excess acquired free energy versus required free energy results in energy storage or growth • Changes in free energy disruptions • Coupled reactions • Chemical work • Electrochemical work • Mechanical work
Coupled Reactions
• Use of an exergonic process to drive an endergonic one ▫ Photosynthesis and respiration ▫ ATP/ADP Cycle
Chemical Work
• Build, rearrange, break apart substances
▫ Polymers from monomers
Electrochemical Work
• Transport – Pumping of substances • Moving charged particles across membranes
Mechanical Work
• Physical Movement
▫ Muscles ▫ Flagella
Metabolic Reactions
• According to the laws of thermodynamics, biochemical reactions may change the form of energy but not the net amount
First Law of Thermodynamics
• Energy cannot be created nor destroyed • Total amount of energy in the universe remains constant
▫ Energy dissipates as heat replenished by sun ▫ Heat = measure of random molecules
Second Law of Thermodynamics
• Energy flows from usable to unusable forms • Disorder in the universe is continuously increasing
▫ Less order = more stable ▫ Entropy = measure of disorder
Entropy Happens!
Second law cont.
• Organisms do not violate the 2nd law • Order is maintained by coupling cellular processes that increase entropy (negative changes in free energy) to those that decrease entropy