Define 'energy'.
The capacity to do work (to cause Change) Potential and Kinetic Energy
Compare potential energy and kinetic energy. Classify different energy forms into one of these two categories.
Potential is stored energy. Kinetic energy is motion energy.
Potential
Chemical Energy - stored in bonds and atoms
Concentration Gradient - stored across membrane
Kinetic
Electrical Energy
Radiant Energy
Thermal Energy
Motion Energy
Explain why cells need energy? Describe the types and examples of cellular work.
All living systems require Energy
Synthetic Work - Biosynthetic pathways
Mechanic Work
Concentration Work
Electrical Work
Generation of Heat
Generation of Light
Define an organism based on its energy-converting abilities (e.g. autotroph, heterotroph, chemotroph, phototroph, photoautotroph, chemoheterotroph).
Autotroph - organism that produce organic compounds form inorganic molecules
Heterotrophs - organisms that produces organic compounds starting from other organic molecules
Phototroph - able to capture light E and transform into chemical E
Chemotroph - obtains energy by oxidizing bonds in molecules
Explain how energy and matter are used in the biosphere. Specifically explain this statement: "Energy flows through the biosphere while matter is recycled". Explain why energy must be replenished (i.e. heat loss).
Energy flows through biosphere
Flow from sun to earth
Light energy captured by photoautotrophs used to convert inorganic C into organic C
Some Energy lost as heat
Chemotrophs and autotrophs convert organic C into usable E.
Matter cycles in Biosphere
Between phototrophs and heterotrophs
Plants do not make energy from the sun, they convert the energy.
Define 'thermodynamics'.
The study of Energy transformations. Energy can be converted from one form to another. Cells/organisms extract E and use it to perform work
Interpret the first law and second law of thermodynamics. Provide examples to illustrate these laws.
First Law: Energy can be transferred and transformed. Energy cannot be created or destroyed
Second law: Every Energy transfer or transformation increases entropy (disorder) of the universe
Define free energy. Define a 'spontaneous' process.
Delta G = change in free energy
Measure of thermodynamic spontaneity of a system.
Amount of Energy available to do work
Looking at change in system from start to finish
What does deltaG tell us about a system? What does it mean if deltaG is zero?
Gibbs free energy tells us whether a process can occur
To what extent (directionality)
Wont tell us if a process will actually occur
Interpret the meaning of the following equation: ∆G = ∆H - T∆S.
Delta g is the change in free energy, spontaneity of a system
Delta h is change in enthalpy or the heat content of a system
Delta s is change in entropy or disroder of a system
T = temperature (kelvins)
If delta G is less than zero it is spontaneous and exergonic, and if it is greater than 0 it is non spontaneous and endergonic
What happens when deltaG = 0? Explain.
It is at equilibrium and it is most stable
We cannot do work by a system at equilibrium
Interpret a free energy diagram.
yes
Be able to determine for given conditions whether a reaction can proceed spontaneously.
If free energy decreases then it is spontaneous
Define endergonic and exergonic. How do these terms related to deltaG values?
Exergonic is energy released. This is negative delta G
Endergonic is energy required. This is positive delta G
Provide examples of a spontaneous change. How does the initial state of the system compare to the final state?
Jumping off of a diving board, diffusion, and chemical reaction. The initial state has more energy compared to the final state.