BIO 121 Study Guide 5 UPDATED
ACTUAL Exam Questions and CORRECT
Answers
What is metabolism, and what is the difference between anabolism and catabolism? - CORRECT
ANSWER - chemical reactions that occur IN cells
Anabolism - reactions that build molecules
Catabolism - reactions that break down molecules
Why do cells need energy, and what is the difference between potential energy and kinetic
energy? - CORRECT ANSWER - Energy is a cell's ability to do work; maintain processes
associated with life
Potential energy - stored energy; potential energies stored in living systems is chemical energy
stored in chemical bonds in our food
kinetic - energy of motion
What are the first and second laws of thermodynamics? - CORRECT ANSWER - 1) energy
cannot created or destroyed, but can be converted from one form to another
2) Entropy (disorder) of universe always increases (S = entropy)
All things become less ordered because keeping order requires energy
What is free energy? - CORRECT ANSWER - (G) - energy needed to break and form
chemical bonds
, includes enthalpy (H): energy in chemical bods and 2 disordering influences: temperature and
entropy
free energy = ordering influences - disordering influences; ΔG (free energy) = ΔH (enthalpy) -
TΔS(entropy)
chemical reactions usually result in a change in free energy
How can you predict in which direction a reaction will proceed? - CORRECT ANSWER - use
ΔG, change in free energy
-ΔG: exergonic reaction; products have less energy than reactants + give off energy (ex.
firecracker) + spontaneous; lower energy than started with
+ ΔG: endergonic reaction; products have more energy than reactants + absorb energy (ex.
photosynthesis bc add energy from sun); more energy than you started with
What is an exergonic reaction and how does if differ from and endergonic reaction? - CORRECT
ANSWER - Exergonic - A reaction that releases energy; products contain less free energy or
more disorder than reactants; spontaneous
exothermic - reaction that releases heat; spontaneous if ΔS > ΔT; massive increase in entropy
overrides everything else
Endergonic - A reaction that consumes energy (NOT spontaneous)
Why can't thermodynamics tell you how fast a reaction will go? - CORRECT ANSWER -
need to know the activation energy; first need to break existing bonds; reactions with high
activation energies proceed more slowly
ACTUAL Exam Questions and CORRECT
Answers
What is metabolism, and what is the difference between anabolism and catabolism? - CORRECT
ANSWER - chemical reactions that occur IN cells
Anabolism - reactions that build molecules
Catabolism - reactions that break down molecules
Why do cells need energy, and what is the difference between potential energy and kinetic
energy? - CORRECT ANSWER - Energy is a cell's ability to do work; maintain processes
associated with life
Potential energy - stored energy; potential energies stored in living systems is chemical energy
stored in chemical bonds in our food
kinetic - energy of motion
What are the first and second laws of thermodynamics? - CORRECT ANSWER - 1) energy
cannot created or destroyed, but can be converted from one form to another
2) Entropy (disorder) of universe always increases (S = entropy)
All things become less ordered because keeping order requires energy
What is free energy? - CORRECT ANSWER - (G) - energy needed to break and form
chemical bonds
, includes enthalpy (H): energy in chemical bods and 2 disordering influences: temperature and
entropy
free energy = ordering influences - disordering influences; ΔG (free energy) = ΔH (enthalpy) -
TΔS(entropy)
chemical reactions usually result in a change in free energy
How can you predict in which direction a reaction will proceed? - CORRECT ANSWER - use
ΔG, change in free energy
-ΔG: exergonic reaction; products have less energy than reactants + give off energy (ex.
firecracker) + spontaneous; lower energy than started with
+ ΔG: endergonic reaction; products have more energy than reactants + absorb energy (ex.
photosynthesis bc add energy from sun); more energy than you started with
What is an exergonic reaction and how does if differ from and endergonic reaction? - CORRECT
ANSWER - Exergonic - A reaction that releases energy; products contain less free energy or
more disorder than reactants; spontaneous
exothermic - reaction that releases heat; spontaneous if ΔS > ΔT; massive increase in entropy
overrides everything else
Endergonic - A reaction that consumes energy (NOT spontaneous)
Why can't thermodynamics tell you how fast a reaction will go? - CORRECT ANSWER -
need to know the activation energy; first need to break existing bonds; reactions with high
activation energies proceed more slowly
