Enzymes - Fall River Public Schools
Download
Report
Transcript Enzymes - Fall River Public Schools
Catalysts of Life
Review of Chemical Reactions
A chemical reaction is a process that changes, or
transforms, one set of chemicals into another
Reactants are elements or compounds that enter into a
chemical reaction
Products are the elements or compounds produced by a
chemical reaction
Chemical reactions usually require energy to get
started
Activation energy is the energy that is needed to get a
reaction started
What are enzymes?
Enzymes are proteins
that hasten, or speed up,
chemical reactions
A catalyst is a substance
that speeds up the rate
of a chemical reaction
Enzymes are biological
catalysts
Enzymes speed up the
reactions that take place
in cells
How do enzymes work?
The molecule that an enzyme
binds with or acts upon is
called the substrate
The spot on an enzyme
where the enzyme and
substrate bind together is
called the active site.
The active site is made of
deep folds created by the
folding of amino acid chains
Enzymes can be used over
and over again after a reaction
is complete
How do enzymes work?
Enzymes have a specific
shape
Substrates also have a
specific shape
In order for an enzyme
and substrate to bind
together and react, their
shapes MUST fit
together
This is called the lockand-key model
How do enzymes work?
If an enzyme shape does not match with a substrate, there
is no reaction
An enzyme’s shape can be changed if conditions are not
right
If an enzyme’s shape is changed due to changing
conditions, then the enzyme has been denatured
No reaction can occur if an enzyme’s shape is denatured
Factors that affect enzyme shape
pH – too acidic or too basic
Temperature – too hot or too cold
Enzyme concentration – how many enzymes are there?
How do enzymes work?
Web Link:
http://www.lew-
port.com/10712041113402793/lib/10712041113402793/Ani
mations/Enzyme_activity.html
Other factors affecting enzymes
Competitive inhibitors are molecules that are
similar to the substrate’s shape
Competitive inhibitors get stuck in the active site and
prevent the enzyme from binding with the substrate
Noncompetitive inhibitors are molecules that bind
near, but not at, the active site
Noncompetitive inhibitors change the shape of the
active site and prevent the enzyme from binding with
the substrate