Unit 5 1/2. A chemical reaction will occur spontaneously…
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Transcript of Unit 5 1/2. A chemical reaction will occur spontaneously…
Unit 5 1/2
A chemical reaction will occur spontaneously…
but the process may be too slow to be effective, in living cells…
A chemical reaction will occur spontaneously, but the process may be too slow to be effective, in living cells…
ex. hydrolysis of sucrose:
adding water~ they break apart
ex. hydrolysis of sucrose:
energy is required to break the bond between those two carbohydrate molecules,
ex. hydrolysis of sucrose:
+ adding water~ they break apart
Chemical reactions can’t “get started” w/o energy being added
• In other words… ENERGY must be added in order for the reaction to start…
• Kinda like you cannot put keys on a ring… without opening the ring first!
ex. hydrolysis of sucrose:
energy required to break bonds = Activation Energy
it is EXTREMELY HIGH!
ex. hydrolysis of sucrose:
Activation energy!!
ex. hydrolysis of sucrose:
Activation Energy - -
the reaction can occur only when energy is added:
ACTIVATION ENERGY can give off heat
hydrolysis of molecules in your body…
Energy of Activation EA barrier is EXTREMELY high - the reaction will occur only if reactantsed:
Energy of Activation EA barrier is EXTREMELY high - the reaction will occur only if reactants are heated:
Enzymes lower the temperature of the
activation energy -Energy of Activation EA
barrier is EXTREMELY
high - the reaction will occur only if reactants are
heated:
Enzymes lower activation energy so rxn. can occur -
Too hot!!!
AHHHHH!!!
Enzymes lower activation energy this allows chemical reactions to
happen in your body FASTER!!
Bromelain
Pineapple has been used as a medicinal plant in several native cultures and bromelain has been known chemically since 1876.
Bromelain is a digestive enzyme found in the stem and fruit of the pineapple plant
DURKEE meat tenderizer has BROMELAIN
Papain
Its utility is in breaking down the tough meat fibers and has been utilized for thousands of years in its native South America.
It is sold as a component in powdered meat tenderizer available in most supermarkets.
The cheap meat tenderizer had PAPAIN
This is an enzyme called CATALASE
This is an enzyme called CATALASE
It’s active siteIt’s active site
The substrate enters the ezyme’s active site
The substrate enters the ezyme’s active site
EnzymeEnzyme
Enzymes are specific to the molecule with which they attach (substrate)
molecule it attaches molecule it attaches withwith
Stages of an enzyme-catalyzed-reaction:
catalase H2O2
Stages of an enzyme-catalyzed-reaction:
catalase H2O2
Stages of an enzyme-catalyzed-reaction:
Stages of an enzyme-catalyzed-reaction:
catalaseH2O
O2
Energy Energy releasedreleased
Energy Energy releasedreleased
Energy Energy releasedreleased
Energy Energy releasedreleased
Enzymes are affected by environmental factors:
Energy of Activation EA barrier is EXTREMELY high - the reaction will occur only if reactants are heated:
ex. pH
Beyond that temp, speed of reaction drops:
Enzymes do have optimal pH:
Improper pH disrupts Improper pH disrupts bonds in the protein bonds in the protein
……remember, enzymes remember, enzymes are PROTEINare PROTEIN
Enzymes are affected by environmental factors:
ex. temperature
Enzymes are affected by environmental factors:ex. too cold
Enzymes slow down
They cannot “hit” as many substrates
Enzymes are affected by environmental factors:
ex. amount of heat
Too hot… Too hot… DENATUREDDENATURED
Acceptable Acceptable temperature…temperature…
PERFECTPERFECT
Too hot… Too hot… DENATUREDDENATURED
hmmm… hmmm… WHATWHAT would would that do to the that do to the activeactive site?site?
Enzymes do have optimal temperatures:
heatheat disrupts bonds in disrupts bonds in the protein the protein
……remember, enzymes remember, enzymes are PROTEINare PROTEIN
Sometimes enzymes require nonprotein “helpers”
CoEnzymesCoEnzymes
Molecules that are bound to the active site
“A cell is not just a bag of chemicals with
thousands of different kinds of enzymes and substrates wandering
about randomly.”
Control of metabolism-
Chaos would result if all of a cell’s metabolic pathways were open at the same time… chemical reactions must be regulated
Cattle-ist-ist