Enzymes Flashcards
What is activation Energy
is the minimum amount of energy required to start a chemical reaction, and also the energy required to break bonds
(EA) stands for…
activation energy
all reactions possess an _____ barrier that must be overcome for a reaction to occur
activation energy
energy is released when new bonds are….
formed
Enzymes are protein ….
catalysts
all enzymes are proteins, but not all proteins are…….
enzymes
What is a catalyst
A substance that speeds up the rate of a chemical reaction without being used up (consumed) in the reaction
after a reaction, the enzyme is able to catalyze……
another reaction
enzyme names end in
ase
Every chemical reaction involves both
making and breaking bonds
making bonds ________ energy
releases
breaking bonds ________ energy
absorbs
speed up the rate of a reaction by
lowering the………
activation energy
What remains the same in the exergonic and endergonic diagrams
the net change in enthalpy
Enzymes are proteins with…
specific 3-D shapes
What is a substrate?
A substrate is the molecule that an enzyme works on to create a product.
Enzymes are defined by…
chemical bonds
A substrate binds to a …..
particular site
enzymes are _______ to the substrate to which they
bind
specific
location to where the substrate binds to the enzyme is known as the……
active site (complimentary fit)
What is Enzyme-Substrate Complex?
When a substrate binds to an enzyme’s active site, so the reaction can occur.
1st theory of active site
active site is rigid and exactly
complimentary to the substrate (lock and key)
What is Induced-fit Model?
is when an enzyme changes its shape slightly to better fit the substrate, helping the reaction occur.
Induced fit is when..
when enzymes conformation changes to better accommodate the substrate
Rates of chemical reactions are dependent on the what factors?
temperature
pH
concentration of substrate
concentration of enzyme
Inhibitors
Cofactors/Coenzymes
Which chemical reaction are denaturation?
temperature and pH
An enzyme’s three-dimensional shape is defined by various….
chemical bonds
The rate at which an enzyme converts substrate into product can be increased by ___________________.
increasing substrate concentration
there is a limit !
Enzyme is saturated when….
all active sites are occupied by substrates, and the reaction rate can’t increase any further.
Adding more _______ will not increase the rate. But, Adding more _____ will increase the rate.
substrate, enzyme
Cofactors may be…
inorganic or organic
What is cofactor ?
nonprotein chemical compound that helps enzymes to function and work properly.
What is coenzymes
A specific type of organic cofactor, often derived from vitamins.
Inorganic cofactors are typically…
metal ions or molecules
Organic cofactors (“coenzymes”) are typically…
vitamins or are derived from vitamins.
What is Competitive
Inhibition?
Competitive inhibition occurs when a molecule (the inhibitor) competes with the substrate for binding to the enzyme’s active site.
increased [substrate] can
overcome present…
inhibitors
What is noncompetitive Inhibition?
when the inhibitor binds to a site on the enzyme that is not the active site
Noncompetitive inhibition causes a change in…
enzyme shape
When noncompetitive inhibitor changes the shape of enzyme, what happens?
the enzyme cannot bind to the substrate
What is Allosteric Regulation?
when a molecule binds to an enzyme at a site other than the active site, changing the enzyme’s activity by either activating it or inhibiting it.
allosteric regulation can
activate or inhibit
Regulator binding changes shape of
substrate active site
What is an allosteric activator ?
An allosteric activator is a molecule that binds to an enzyme at an allosteric site (a site different from the active site) and increases the enzyme’s activity.
active form is stabilized by an
allosteric activator molecule
inactive form is stabilized by an …
allosteric inhibitor molecule
What are Allosteric Inhibitors?
Molecule that binds to the allosteric site and decreases enzyme activity
Allosteric inhibitor vs activator
Allosteric activator stabilizes active form of enzyme
Allosteric inhibitor stabilizes inactive form of enzyme.
many poisons act by…
inhibiting enzymes
many antibiotics inhibit….
bacterial enzymes
What is Feedback Inhibition?
Feedback inhibition is when the end product of a process inhibits an enzyme earlier in the pathway, stopping the process to prevent overproduction.
When is end product produced in feedback inhibition
when needed
in many cases, this
end-product acts as an
_________ of an enzyme
Inhibitor
What is exothermic (Exergonic) reaction?
When the reactant is higher than the product, energy is released and makes bonds.
What is endothermic (endergonic) reaction?
When the product is higher than the reactant, energy is absorbed and bonds are broken.
Substrates act on what
sucrose
Enzymes decrease _______________, but increases the _________________
activation energy, rate of reaction
Substrates come to enzymes or enzymes come to substrates?
Substrates come to enzymes, not the other way around. The concentration remains the same
Enzyme pH in stomach is..
2
When you remove one phosphate from ATP, what does it become?
ADP
