• Warm-up What are the four macromolecules and their function?

Warm-up
•What are the four macromolecules
and their function?
Mindstretcher
1. What is the name of the region at which reactants bind to an enzyme during
a biochemical reaction?
a) Catalyst
b) Product
c) Substrate
d) Active site
Mindstretcher
2. How are enzymes able to speed up biochemical reactions?
a) They provide energy to the reactants.
b) They absorb energy from the products.
c) They lower the activation energy of the reaction.
d)They increase the number of available reactant particles.
Mindstretcher
3. The diagram below shows a single glucose molecule.
This molecule is also referred to as
a) A polysaccharide
b) A monosaccharide
c) A fatty acid
d)A nucleic acid
Enzymes
Metabolism
• The totality of an organism’s chemical
processes, involving thousands of precisely
coordinated, complex, efficient and integrated
chemical reactions in the cell.
Enzymes are “biological catalysts”:
they make all the chemical reactions happen in the
cell!
Enzymes = “biological catalysts”
• Catalyst = chem agent
that accelerates a
reaction without being
permanently changed
• Protein
• Specific
• Reusable
Catalyst: something that speeds up a
chemical reaction
Enzyme: proteins that speed up/help jump
start reactions in an organism
Therefore enzymes are catalysts because
they speed up biochemical reactions
• We need enzymes for every process that
happens in our bodies!
e.g. Digesting food, replicating DNA
Enzymes
Substrate: the material that an enzyme
binds to and breaks down
Complex: enzyme and substrate together
Active site: Where the enzyme and
substrate bind together
Enzymes
Enzymes often end in -ase
•
•
•
Lactase breaks down lactose
Amylase breaks down amylose
Make up your own enzyme-substrate
names. Write on your paper
Quick Check
1. What’s a substrate?
2. What do enzymes usually end in?
3. Is catalase an enzyme or a substrate? How do
you know?
4. What do you predict is the substrate for the
enzyme sucrase?
Enzyme Specificity
Enzymes are specific:
• They only work with one substrate
• The enzyme and the substrate fit together like a lock and
a key
Enzymes are reusable: meaning _________
therefore the enzyme is not changed during a reaction
The substrate is changed, it becomes the product(s)
Activation Energy
• For reaction to occur,
reactants must absorb
energy to break bonds
• Activation Energy is
the amount of energy
reactant molecules
must absorb to start a
chemical reaction.
Enzymes Lower Activation Energy
• Stress bonds for
catabolism
(breakdown)
• Orient molecules for
anabolism (building)
• Provide microenv. that
facilitates the reaction
Catalytic Cycle of Enzymes
• Enzymes Factors
are proteins
Affecting Enzyme Activity
• Proteins are long chains of amino acids
folded
into a very specific shape
• The function of every protein depends on
its
structure or shape
• Change the shape of an enzyme and it
won’t work
• What would change the shape of an
enzyme?
Factors Affecting Enzyme Activity
• Temperature—increase temp, increase
reaction rate, until heat denatures protein
• pH – most optimal from 6-8
• Ionic conc. – most enz cannot tolerate high
salinity
• Many adaptations are exceptions to above
Destroying Enzymes
An enzyme’s job is determined by its SHAPE
Denature: enzyme changes shape so that it
no longer works properly
Enzymes are denatured by high temperatures and low pHs.
Optimum Temperature and pH
1. Find the highest point on the curve.
2. Drop down to the x-axis.
3. Record temperature or pH.
Factors Influencing Rate of Enzyme Action:
pH
pH - the optimum (best) in most living things is close to
7 (neutral)
• high or low pH levels usually slow enzyme activity
• A few enzymes (such as gastric protease) work best
at a pH of about 2.0
Factors Influencing Rate of Enzyme
Action: Temperature
Temperature - strongly influences enzyme activity
• optimum temperature for maximum enzyme function
is usually about 35-40 C.
• reactions proceed slowly below optimal temperatures
• above 45 C most enzymes are denatured (change in
their shape so the enzyme active site no longer fits
with the substrate and the enzyme can't function)
Factors Influencing Rate of Enzyme Action:
Concentrations of Enzyme and Substrate
• When there is a fixed amount of enzyme and an
excess of substrate molecules -- the rate of
reaction will increase to a point and then level off.
Enzymes (Notes)
enzyme
lactase
lactose + H2O
substrate
glucose + galactose
products
Enzyme Foldable
SUBSTRATES A &
B
1
2
ENZYMESUBSTRATE
COMPLEX
ENZYME
3
PRODUCT AB
4
\
ENZYME
TAB 1
•
•
ENZYME: proteins that act as catalyst to speed up
chemical reactions in living cells.
SUBSTRATE: the substance and enzyme acts on
Induced Fit:
ACTIVE SITE: a region of an
enzyme molecule which the
substrate binds to
•A change in the shape of an
enzyme’s active site
•Induced by the substrate
Tab 2
Tab 3
Factors that Affect Enzyme
Action:
• pH
• Temperature
• Amount of substrate
• Reusable or NOT reusable? Reusable
Tab
4
• Specific or not specific? Specific
•
Effect on chemical bonds that join atoms in molecules:
•
•
Break bonds or
Make bonds
• What macromolecule? Enzymes always protein
• Examples of biological catalysts: Protease, Lactase,
Amylase
Question 1
What are proteins that speed up
chemical reactions called?
A. Amino acids
B. Reactants
C. Enzymes
D. Substrates
Question 2
What is a substrate?
A. The compound that is before the arrow in a
chemical reaction
B. Another name for an enzyme
C. The material that an enzyme binds to
D. The term used to describe the structure
formed after an enzyme binds with a complex
Question 3
How do enzymes affect the activation energy of a
chemical reaction?
A. Enzymes increase the activation energy
needed for a reaction to start
B. Enzymes decrease the activation energy
needed for a reaction to start
C. Enzymes do not alter activation energy of
chemical reactions
D. Enzymes initially decrease activation energy
than increase it
Question 4
Which of the following statements best
describes enzymes?
A. enzymes cannot be reused after a reaction
B. Enzymes are organic catalysts
C. Enzymes slow down chemical reactions
D. Enzymes can bind to any substrate
Question 5
An enzymes job is determined by its what?
A. size
B. shape
C. color
D. Activation energy
Question 1
What are proteins that speed up
chemical reactions called?
A. Amino acids
B. Reactants
C. Enzymes
D. Substrates
Question 2
What is a substrate?
A. The compound that is before the arrow in a
chemical reaction
B. Another name for an enzyme
C. The material that an enzyme binds to
D. The term used to describe the structure
formed after an enzyme binds with a complex
Question 3
How do enzymes affect the activation energy of a
chemical reaction?
A. Enzymes increase the activation energy
needed for a reaction to start
B. Enzymes decrease the activation energy
needed for a reaction to start
C. Enzymes do not alter activation energy of
chemical reactions
D. Enzymes initially decrease activation energy
than increase it
Question 4
Which of the following statements best
describes enzymes?
A. enzymes cannot be reused after a reaction
B. Enzymes are organic catalysts
C. Enzymes slow down chemical reactions
D. Enzymes can bind to any substrate
Question 5
An enzymes job is determined by its what?
A. size
B. shape
C. color
D. Activation energy