Download Enzyme - Mercer Island School District

Enzyme
• A protein that acts as a biological catalyst
– Catalyst: Any chemical that ______________
reaction but is not _____________ by the reaction
– Enzymes are therefore ___________ .
• Enzymes ___________ (decomposition) or put
together (______________) molecules.
– They act as scissors (decomposition) or glue
(synthesis)
Enzyme act as Catalysts
An enzyme is a protein that catalyzes a specific
chemical reaction by _____________________
_________________ .
Activation Energy
The amount of _____________ required to
__________ a chemical reaction.
Even reactions that give off energy may require a
large amount of energy to begin.
Example: The activation energy of paper burning is
451 degrees Fahrenheit
By ______________ the activation energy, enzymes
allow reactions to occur at body temperature that
would otherwise require ______________________.
Example: The breakdown of sugar into carbon
dioxide and water.
Enzymes
The enzyme is not ___________ in the reaction and
can catalyze the same reaction repeatedly.
A substrate is a ____________ in an enzyme
catalyzed reaction. (Example: starch is the
substrate of the enzyme amylase)
Enzyme Reactions
(Decomposition)
Substrate
Activation
Site
Enzyme
• The ____________ of an enzyme is very
important. It creates an ___________ that
will only react with a certain molecule based
on its ___________.
– Substrate: What is being __________ with help
from that enzyme
– Active Site: where the substrate(s) _________.
• Enzyme names typically end with “______”
– Amylase, lipase, peroxidase
Enzyme Reactions (Synthesis)
Enzyme Reactions
3. ____________________are
Enzyme
formed and the enzyme
begins reacting with
Activation Site
other substrates again.
A and B
Products
1. Enzyme And
Substrate A-B
____________
2. Reaction Occurs
When the _________ is made
Substrate A-B
Different Enzyme Reactions
Enzyme Cofactors
• ______________ are inorganic molecules that are
incorporated within enzymes that allow the enzyme to
_______. These are often _________ and ___________.
Eat your
Fruits &
Veggies!
Rate of Reaction
• Rate of the reaction: The time it takes for _____
______________________________________
______________________________________
• Certain conditions will affect the rate of reaction
for any type of reaction:
–
–
-
What do all of these factors have in common?
They all increase the _____________
_____________ between the reactants.
Higher temperature increases the rate of
collisions because ______________________
______________________________________
Rate of Reaction for Enzymes
• All the previous factors also affect an
enzyme’s rate of reaction.
• Since enzymes are ______________ with
specifically shaped _______________, the
________________ (unfolding) of an enzyme
also affects its ability to _________________ .
• Extreme _____________ and extreme
______conditions denature enzymes and will
__________ the reaction rates.
High
temperature or
____and ____
ions in extreme
pH solutions
disrupt the ionic
and hydrogen
________
between the
amino acids
causing the
polypeptide
chain to ______.
Denaturation of an Enzyme
The unfolded protein changes the shape
of the __________ not allowing substrates
to ______ .
Temperature and Reaction Rate
of Enzymes
1. As the temperature goes up enzymes and
substrates move ___________.
2. This means they __________ with each
other more___________and the reactions
will take place at a _________ rate.
3. At high temperatures the enzymes begin to
_________ (change shape) and no longer
work because they cannot ____________
_______________________________ .
Temperature and Reaction Rate
Enzyme begins
To denature
pH and Reaction Rate
1. Enzymes only work in a certain _______ of
pH.
2. Enzymes ____________ when the pH is too
_______ or to _____.
•
•
Pepsin (found in the stomach) needs a lower pH
(____________)
Amylase (found in saliva) needs a higher pH
Concentration and Reaction Rate
1. Enzyme ___________ is typically _____
compared to ___________ concentration
2. Increasing the concentration of
substrates or enzymes will increase the
__________________.
Review of Concepts
• 1. How do enzymes speed up reactions?
• 2. What do you call the location on an enzyme
where the reactants bind?
• 3. What do you call the specific reactants for a
certain enzyme?
Review Continued
• 4. What environmental factors would cause an
enzyme to change its shape (denature)?
5. Describe why reaction rates between
substrates and enzymes would decrease due to
lower temperatures.
Review Continued
• 6. Describe why enzyme activity increase in section A
and why enzyme activity decreases in section B.
• A)
• B)
A
B