chapter 8: energy and metabolism - auburn · pdf filemetabolism: anabolism + catabolism ......

.
Chapter 8: Energy and
Metabolism Why do organisms need energy? How do organisms
manage their energy needs?
Defining terms and issues:
energy and thermodynamics
metabolic reactions and energy transfers
Harvesting and using energy
ATP is the main energy currency in cells
energy harvesting (redox reactions)
Regulating reactions: Enzymes
http://www.auburn.edu/academic/classes/biol/1020/bowling/

.
Discuss energy conversions and the 1st
and 2nd law of thermodynamics.
Be sure to use the terms
work
potential energy
kinetic energy
entropy
What are Joules (J) and calories (cal)?

.
Chapter 8: Energy and
Metabolism Why do organisms need energy? How do organisms
manage their energy needs?
Defining terms and issues:
energy and thermodynamics
metabolic reactions and energy transfers
Harvesting and using energy
ATP is the main energy currency in cells
energy harvesting (redox reactions)
Regulating reactions: Enzymes

.
Energy and Thermodynamics
energy for work: change in state or motion of matter

.
expressed in Joules or calories
1 kcal = 4.184 kJ

.
expressed in Joules or calories
1 kcal = 4.184 kJ
energy conversion: energy form change
potential / kinetic

.
Energy and Thermodynamics potential energy (capacity to do work)

.
Energy and Thermodynamics potential energy (capacity to do work)
kinetic energy (energy of motion, actively performing work)
chemical bonds: potential energy
work is required for the processes of life

.
Discuss energy conversions and the 1st
and 2nd law of thermodynamics.
Be sure to use the terms
work
potential energy
kinetic energy
entropy
What are Joules (J) and calories (cal)?

.
Laws of thermodynamics describe the constraints on

.
The laws of thermodynamics are
sometimes stated as:
Explain.

.
Laws of Thermodynamics
First law:
the total amount of energy (+ matter) in a closed system remains constant

.
First law:
also called conservation of energy

.
First law:
also called conservation of energy
note:
the universe is a closed system
living things are open systems

.
Second law: in every energy conversion
some energy is converted to heat energy
heat energy is lost to the surroundings
heat energy cannot be used for work

.
energy converted to heat in the surroundings
increases entropy (spreading of energy)

.
energy converted to heat in the surroundings
increases entropy (spreading of energy)
thus, this law can also be stated as:
Every energy conversion increases the entropy
of the universe.

.
Laws of Thermodynamics Second law:
Upshot: no energy conversion is 100% efficient
Just to maintain their current state, organisms must get a constant influx of energy because of energy lost in conversions

.
The laws of thermodynamics are
sometimes stated as:
Explain.

.
Differentiate between:
anabolism and catabolism
exergonic and endergonic reactions

.
Metabolism: anabolism + catabolism
metabolism divided into
anabolism (anabolic reactions)
anabolic reactions are processes that build complex molecules from simpler ones

.
Metabolism: anabolism + catabolism
metabolism divided into
anabolism (anabolic reactions)
anabolic reactions are processes that build complex molecules from simpler ones
catabolism (catabolic reactions)
catabolic reactions are processes the break down complex molecules into simpler ones

.
Differentiate between:
anabolism and catabolism
exergonic and endergonic reactions

.
Chemical Reactions and Free Energy
Chemical reactions involve
changes in chemical bonds

.
changes in substance concentrations

.
changes in substance concentrations
changes in free energy
free energy = energy available to do work in a chemical reaction (such as: create a chemical bond)
free energy changes depend on bond energies and concentrations of reactants and products
bond energy = energy required to break a bond; value depends on the bond

.
left undisturbed, reactions will reach dynamic equilibrium when the relative concentrations of reactants and products is correct
forward and reverse reaction rates are equal; concentrations remain constant

.
left undisturbed, reactions will reach dynamic equilibrium when the relative concentrations of reactants and products is correct
forward and reverse reaction rates are equal; concentrations remain constant
cells manipulate relative concentrations in many ways so that equilibrium is rare

.
exergonic reactions the products have less free
energy than reactants
the difference in energy is released and is available to do
work

.
Chemical Reactions and Free Energy exergonic reactions the products have less free energy than reactants
the difference in energy is released and is available to do work
exergonic reactions are thermodynamically favored; thus, they are spontaneous, but not necessarily fast (more on activation energy later)

.
catabolic reactions are usually exergonic
ATP + H2O ADP + Pi is highly exergonic

.
endergonic reactions the products have
more free energy than the reactants
the difference in free energy must be supplied
(stored in chemical bonds)
http://www.auburn.edu

chapter 8: energy and metabolism - auburn · pdf filemetabolism: anabolism + catabolism ......

Documents