Text Chapters 2 and 4: Chemical Reactions in Cells Flashcards
Energy
the capacity to do work
First Law of Thermodynamics
in a closed system, energy is neither created nor destroyed but can be converted from one form to another
Second Law of Thermodynamics
energy conversions result in a loss of useful energy (increase in entropy= randomness)
Chemical Reaction
involves the breaking and formations of chemical bonds
Endergonic Reactions
energy is consumed- (products are GREATER than reactants (ex. photosynthesis)
Exergonic Reactions
energy is released- products are LESS than reactants (ex. burning glucose)
ATP for Short-term Energy Storage
energy is stored in the bonds of ATP- when energy is released, ATP loses a phosphate, is broken down into ADP
Use of Electron Carriers for Donation to Chemical Reactions in the Cell
electron carriers donate electrons to the electron transport chain to produce ATP
Coupled Reactions
energy released from an exergonic reaction is used to power an endergonic reaction
Activation Energy
the least amount of energy required to activate atoms or molecules to a state in which they can undergo a chemical reaction.
Active Site
region on enzyme where reactants bind
Catalyst
speeds up a reaction without being changed by the reaction
Enzyme
a biological catalyst specific for the reactants (substrates) in the reactions they catalyze
-speed up biological catalysts by lowering the activation energy for the reaction
Substrate
the molecule acted upon by an enzyme
Product
a substance that is formed as a result of a chemical reaction
Protein Enzymes (influence)
speed up reactions without changing (catalysts)
Affect of Temperature on Enzyme Activity
colder temperature, less molecular motion, fewer collisions between enzymes and substrate. Enzymes unfold with heat.
Affect of pH on Enzyme Activity
enzymes unfold if too low or too high from optimal pH
Affect of Activators on Enzyme Activity
speed reaction rate
Affect of Inhibitors on Enzyme Activity
lower reaction rate
Feedback Inhibition
end product inhibits first enzyme
Competitive Inhibitors
bind to the active site and prevent the substrate from binding
Non-competitive Inhibitors
bind somewhere else on the enzyme, change the shape of active site, prevent substrate from binding
Affect of Enzyme Concentration on Enzyme Activity
raises the rate of enzyme activity until it cannot be raised anymore
