Chapter 6 Flashcards
Metabolism
- emergent property
- totality of organisms’ chemical reactions
Metabolic Pathway
begins with specific molecule and ends with product; each step is catalyzed by a specific enzyme.
Catabolic Pathway
release energy through breaking down molecules into simple compounds
Anabolic Pathway
consumes energy to build complex molecules from simple ones
Bioenergetics
study of how energy flows through living organisms
Energy
capacity to cause change
Kinetic Energy
motion
Heat/Thermal Energy
kinetic energy associated with random movements of atoms and molecules
Potential Energy
energy that matters possess due to its location or structure
Chemical Energy
potential energy available for reuse in a chemical reaction
Thermodynamics
study of energy transformations
In an open system energy and matter can be transferred between….
the system and its surroundings
First Law of Thermodynamics
energy of the universe is constant
Second Law of Thermodynamics
every energy transfer or transformation increases entropy of universe
For a process to occur without energy input, it must…
increase entropy of the universe
During every energy transfer or transformation some energy is…
unusable and lost as heat
Entropy may decrease in an organism but the universes total entropy..
increases
organisms replace ordered forms of matter and energy with…
less ordered forms
Energy flows into ecosystem as light and exists…
in the form of heat
What is a living system’s free energy?
the energy that can do work when temperature and pressure are uniform
Change in free energy is related to change in enthalpy, ….., and ….
- change in entropy
- temperature
Enthalpy
change in total energy
Only processes with a negative change in free energy are
spontaneous
Exergonic Reaction
- net release of free energy and is spontaneous
- change in free energy is negative
Endergonic Reactions
- absorbs free energy from surroundings and is not spontaneous
- change in free energy is positive
Reactions in a closed system eventually reach what?
equilibrium
Cells are not in equilibrium because?
they are open systems experiencing a constant flow of materials
Energy Coupling
use of an exergonic process to drive an endergonic one
- mediated by ATP
What can break bonds among phosphate groups in ATP?
Hydrolysis
What does ATP hydrolysis produce?
ADP, ATP hydrolysis releases energy
Phosphorylation
regenerates ATP
ATP Cycle
catabolic to anabolic
Enzyme
macromolecule that acts as catalyst
Activation Energy
energy required to start a reaction, breaks bonds in reactants
What supplies activation energy (EA)
heat that reactants absorb
Heat is what kind of catalyst and how does it affect proteins?
Heath is a nonselective catalyst and denatures proteins
How do enzymes catalyze reactions?
lowering activation energy barrier without being consumed
Substrate
reactant molecule an enzyme acts on
Active Site
region where and enzyme binds to substrate
Included fit
binds chemical groups of active site together
An active site can lower …. and speed up ….
- activation energy
- reactions
How can you increase substrate concentration?
speed up enzyme catalysis
How does enzyme saturation affect reaction speed?
The reaction speed is sped up by adding more enzyme
Cofactors
nonprotein molecules carrying out processes too difficult for amino acids
Competitive Inhibitors
bind to active site of enzyme and prvent substrate binding
Noncompetitive Inhibitors
bind to alternative site on enzyme =, causing active site to become less effective
Toxins are what kind of enzyme inhibitors?
Irreversible (COVALENT BONDS)
Cooperativity
binding one substrate molecule to active site of one subunit, locking all other subunits into active shape.
