2.4 Chemical Reactions Notes
Key Concept: Life depends on chemical reactions.
Name ______________________________
Date _____________ Period ___________
Bonds break and form during chemical reactions.
-Chemical reactions chance substances into different once by breaking and forming chemical bonds.
-_____________________________________ during a chemical reaction.
- ____________________________________ by a chemical reaction.
Chemical reactions release or absorb energy.
-Activation energy is the amount of energy that needs to be absorbed to start a ___________________.
Exothermic reactions release more energy than they absorb.
-Reactants have higher bond energies than products.
-Excess excess energy _____________________________ by the reaction.
-_____________________________ the reaction. (Exo = Exit)
Endothermic reactions absorb more energy than they release.
- Reactants have lower bond energies than products.
-____________________________________ by the reaction to make up the difference.
-_____________________________ the reaction. (Endo= “into”)
2.5 Enzymes
Key Concept: Enzymes are catalysts for chemical reactions in living things.
A catalyst lowers activation energy.
-Catalysts are substances that ______________________________________________________
-Decrease activation energy***
-Increase reaction rate***
Enzymes allow chemical reactions to occur under tightly controlled conditions.
-Enzymes are ___________________________________________________.
-Enzymes are needed for almost all processes.
-Most ___________________________________________________.
An enzyme’s structure allows only certain reactants to bind to the enzyme.
-Substrate: ________________________________________________________________________
-Active site: _______________________________________________________________________
Lock and key model shows how enzymes function
-Substrates are ________________________________________________ of the enzyme.
-Enzyme ________________________________________________________________.
-Reaction forms a product that is _____________________________________________.
-Enzyme remains unchanged and can be used again & again.
Disruptions in homeostasis can prevent enzymes from functioning.
-Enzymes function best in a small range of conditions.
-__________________________________________________ can break hydrogen bonds.
- An enzyme’s _________________________________________________________.
Concentration of enzyme & substrate can also affect enzyme function.
-Enzyme concentration: If the concentration of the substrate is kept constant and the concentration
of the enzyme is increased, the rate of reaction increases linearly.
-If the concentration of enzyme is _____________, the reaction rate _______________.
-Substrate concentration: If the concentration of the enzyme is kept constant and the
concentration of the substrate is increased, initially, the rate increases with substrate concentration, until the
rate levels out and remains __________________.