7: Energetics of Living Systems Flashcards
Module 2, Lesson 1
The ultimate source of energy used in biological systems is usually…
The Sun
Photosynthetic organisms use ____ to store chemical energy.
Chemical bonds in sugars
____ is the branch of chemistry concerned with energy changes.
Thermodynamics
Energy is defined as…
The capacity to do work
____ energy is the energy of motion.
Kinetic
____ energy is energy that is stored.
Potential
List examples of types of energy.
(nine total)
- Kinetic
- Potential
- Chemical
- Mechanical
- Heat
- Sound
- Electric Current
- Light
- Radioactivity
____ is a measurement of energy.
Heat
A calorie is defined as the…
Heat required to raise the temperature of 1 gram of water by 1 degree Celsius.
Cells convert energy into different forms via…
Redox reactions
____ occurs when an atom or molecule loses electron(s).
Oxidation
____ occurs when an atom or molecule gains electron(s).
Reduction
An atom or molecule that loses electrons is said to have been…
Oxidized
An atom or molecule that gains electrons is said to have been…
Reduced
True or false:
A particle that has been reduced has greater energy than a particle that has been oxidized.
True
____ occur when an oxidation and reduction reaction take place together.
Oxidation-reduction reactions
(Redox reactions)
A particle that is oxidized transitions to a ____ energy state.
Lower
A particle that is reduced transitions to a ____ energy state.
Higher
The first law of thermodynamics states that…
Energy cannot be created or destroyed; it can only change from one form to another.
During conversion, some energy is lost as…
Heat
True or false:
The total amount of energy in the universe is constant.
True
The second law of thermodynamics states that…
The entropy (disorder) of the universe is constantly increasing.
True or false:
Energy spontaneously converts from a more stable/less ordered form to a less stable/more ordered form.
False
Disorder occurs spontaneously, but an energy input is needed to increase order.
The energy available to do work is called…
Gibbs free energy
(G)
G = H - TS, where…
G = free energy
H = enthalpy
T = absolute temperature (K)
S = entropy
____ is the energy contained in chemical bonds.
Enthalpy
A change in free energy is denoted as…
ΔG
We can use ΔG to predict whether…
A reaction will occur spontaneously
A reaction in which ΔG is ____ will not occur spontaneously.
Positive
The products in a reaction where ΔG is positive will have ____ free energy than the reactants.
More
A reaction that does not occur spontaneously is termed…
Endergonic
A reaction in which ΔG is ____ will likely occur spontaneously.
Negative
The products in a reaction where ΔG is negative will have ____ free energy than the reactants.
Less
Reactions that occur spontaneously are termed…
Exergonic
True or false:
A spontaneous chemical reaction may still require energy in order to begin.
True