Biology Ch. 6
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137 Terms
Energy
ability to promote change or do work
What are the two forms of energy?
Kinetic and potential
Kinetic energy
associated with movement
potential energy
due to structure or location
Chemical Energy
The energy in molecular bonds, is a form of potential energy
first law of thermodynamics
Energy can be transferred and transformed, but it cannot be created or destroyed.
Law of conservation of energy
second law of thermodynamics
Transfer of energy form one form to another increases the entropy of a system. As entropy increases, less energy is available for organisms to use to promote change
Can magnets generate energy on their own?
No.
What does increase the entropy mean?
increase of disorder
Total Energy =
usable energy + unusable energy
Free energy (G) =
amount of energy available to do work (also called Gibbs free energy)
enthalpy
total energy of a system
H =
Enthalpy
G=
Free energy
S=
Entropy
T=
Absolute temp in Kelvin
Equation: H=
G+TS
How do spontaneous reactions occur?
Occurs without input of additional energy
At what rate do spontaneous reactions occur?
slowly and rapidly. It just depends
Breakdown of sucrose into CO2 and H2O is what kind of reaction?
spontaneous
Is the breakdown of sucrose a fast or slow reaction?
slow
key factor in spontaneous reactions
free energy change
What does Delta G mean?
Change in G aka Change in free energy
Exergonic is what kind of reaction? (spontaneous or not spontaneous)
spontaneous
What does Delta G tell us?
the type of reaction
A reaction is exergonic when the Delta G is....
negative
A reaction is endergonic when the Delta G is...
positive
Exergonic reactions do what with energy?
They release energy
What does an endergonic reaction require to drive the reaction?
Addition of energy
(Equation) Delta G =
delta H - T delta S
Delta G = _________ kcal/mol
7.3
What does ATP mean?
adenosine triphosphate
Hydrolysis of ATP favors _______________ of products
formation
Cells use ATP hydrolysis to __________ __________________
drive reactions
An ______________ _____________________ can be coupled to an ________________ _______________
endergonic reaction, exergonic reaction
Hydrolysis of ATP. The reactions will be spontaneous if the _____ ___________ __________ __________ for both processes is __________
net free energy change, negative
ATP drives what kind of reaction?
Endergonic
Catalyst
An agent that speeds up the rate of a chemical reaction without being consumed during the reaction
Enzymes
Protein catalyst in living cells
Ribozymes
RNA molecules wit catalytic properties
Activation Energy
Initial input of energy to start a reaction
Activation energy allows molecules to....
get close enough to cause bond rearrangement
How to overcome activation energy
large amounts of heat and using enzymes to lower activation energy
activation energy helps to achieve what state where bonds are stretched
transition
Enzymes are a target for ...
medications
How enzymes lower activation energy
Straining bonds in reactants to make it easier to achieve transition state
Positioning reactants together to facilitate bonding
Changing local environment
Direct participation through very temporary bonding
"ase" =
enzymes
amalase degrades....
starch
High specificity =
binds with very few things
Low specificity =
binds with many things
Enzymes have a ________ specificity for their substrate
high
Lock and Key metaphor
only the right key (substrate) will fit in the lock (enzyme)
Induced fit phenomenon
interaction also involves conformational changes
Saturation
plateau where nearly all active sites are occupied by substrate
Saturation velocity is...
max velocity.
Vmax is ....
velocity of reaction newar maximal rate
Michaelis constant
A constant, Km, that is a measure of the kinetics of an enzyme reaction and that is equivalent to the concentration of substrate at which the reaction takes place at one half its maximum rate.
High km needs a higher
substrate concentration
Low kn = what specificity
high specificity
High km = what specificity
low specificity
As you get more substrate, you approach the...
velocity
affinity
an attraction to
Competitive inhibition Characterisitics
Molecules bind to active site
Inhibits ability of substrate to bind
Apparent km increases - more substrate needed
Noncompetitive inhibition Characteristics
Lowers Vmax without affecting Km
Inhibitor binds to allosteric site, not active site;
Competitive inhibition gives more ___________ to get to velocity
substrate
Noncompetitive inhibition causes a ____________ _______________ in enzyme
confirmational change
The reaction speed ____________ in a noncompetitive inhibition
lowers
Prosthetic groups
small molecules permanently attached to the enzyme
Cofactor
usually inorganic ion that temporarily binds to enzyme
Coenzyme
organic molecule that participates in reaction but left unchanged afterward
Enzymes function best at...
optimal pH and optimal temperature
What happens to enzymes when they are in too high of temperatures?
They denaturize
What temperature is optimal for enzymes?
37C
Chemical reactions occur in ____________ pathways
metabolic
Is each step of a metabolic pathway catalyzed by a specific enzyme?
yes
2 components of catabolic pathways
breakdown of cellular components
exergonic
3 components of anabolic pathways
synthesis cellular components
endergonic
Must be coupled to exergonic reaction
Generic metabolic pathway
Catabolic reactions are used for _________ building blocks
recycling
Catabolic reactions are used for __________ to drive endergonic reactions
energy
What is NADH
electron carrier
(Catabolic Reactions) energy is stored in ____________ such as ATP, NADH
intermediates
2 ways to make ATP
Substrate-level phosphorylation
Chemiosmosis
substrate-level phosphorylation
enzyme directly transfers phosphate from one molecule to another molecule
Chemiosmosis
energy stored in an electrochemical gradient is used to make ATP from ADP and Pi
Can ions go through the membrane?
no
What does the O.I.L.R.I.G. acronym stand for?
oxidation is loss, reduction is gain
Oxidation
loss of electrons
Note 
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