Section 2.4 Enzymatic reactions
Formative assessment
1. An enzyme is what type of molecule?
Carbohydrate
Lipid
Nucleic acid
Protein
Sugar
r
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Su
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Pr
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L ip
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A.
B.
C.
D.
E.
C
B
d
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2. Cells need enzymes because they:
A. Speed up chemical
reactions for their
particular substrate
B. Act as biological (organic)
catalysts
C. Lower activation energy,
making the reaction more
likely to start
D. A and B
E. A, B, and C
3. Activation energy is :
tt
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de
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A. Chemical potential energy
stored in the substrate
B. Chemical potential energy
stored in the product
C. Energy released after the
chemical reaction
D. Energy needed to start the
chemical reaction
E. Energy needed to allow the
substrate to bind to the active
site.
5. Which part of the graph shows the activation
energy for the enzyme catalyzed reaction?
C
B
D
0%
0%
0%
D
0%
C
A
B
A
B
C
D
A
A.
B.
C.
D.
6. The part of an enzyme where
substrate binds is?
A. Product
B. Active site
C. Enzyme substrate
complex
D. Protein
E. Sugar
pl
e
m
co
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En
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Pr
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7.
All enzymes require an optimal pH, salt concentration,
and temperature because under other conditions the
protein may _____?
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.
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Be
A. Be denatured.
B. Be converted to a
carbohydrate.
C. Be broken down to
amino acids.
D. Be converted to a
lipid.
E. Be too active as a
catalyst.
A.
B.
C.
D.
E.
C12H22O11
C12H22O11 & H2O
C6H12O6
H2O and C6H12O6
C12H22O11 & H2O
& C6H12O6
&
H2
O
0%
2O
11
6
C6
H1
2O
0%
C6
H1
2O
6
0%
C1
2H
2
0%
an
d
0%
H2
O
Which is(are) the reactants of the chemical
reaction described in this chemical equation ?
C12H22O11 + H2O
2C6H12O6
C1
2H
C1
22
2H
O1
22
1
O1
1
&
H2
O
8.
A. Products
B. Active sites
C. Substrates
te
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ts
When they are bound to an enzyme, the
reactants of a chemical equation are called:
Pr
od
uc
9.
10 Enzymes are specific types of which
biological macromolecule?
Carbohydrates
Proteins
Lipids
Nucleic acids
0%
Nu
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ic
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s
s
0%
L ip
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0%
Pr
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Ca
r
A.
B.
C.
D.
11 The molecule on which an enzyme acts:
Catalyst
Substrate
Metabolism
Homeostasis
eo
st
as
Ho
m
M
et
a
bo
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te
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is
0%
ism
0%
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bs
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ys
t
0%
Ca
t
A.
B.
C.
D.
12 Enzymes stop functioning if:
..
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w
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ith
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to
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ey
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al
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om
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at
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...
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Th
A. They act on a
substrate
B. They become
denatured due to
improper pH or
temperature
C. They catalyze too
many reactions
D. They bind with the
wrong substrate
Passive
Endothermic
Exothermic
Denatured
at
ur
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0%
De
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Ex
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En
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Pa
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A.
B.
C.
D.
13 When proteins, such as enzymes,
lose their specific shape they have
become __________.
14 What is the optimum pH for the enzyme pepsin, the
stomach enzyme that digests protein?
A.
B.
C.
D.
1
2.5
5
6.5
100%
pepsin
trypsin
90%
80%
70%
60%
50%
40%
30%
20%
10%
0%
0%
0%
0%
0%
15 What is the optimum pH for the enzyme trypsin, the
small intestinal enzyme that digests protein?
A.
B.
C.
D.
1
2.5
5
6.5
100%
pepsin
trypsin
90%
80%
70%
60%
50%
40%
30%
20%
10%
0%
0%
0%
0%
0%
16 Examine the graph of enzyme activity versus temperature,
then choose the most probable explanation of the data.
.. .
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ee
B.
The enzyme whose rate is shown
in blue has optimal activity at 37°C
but is denatured at 4°C
The enzyme shown in red has a
optimal temperature of 37°C, but
is denatured at 4°C
The organism which uses the
enzyme shown in blue is likely to
be a mammal, but the enzyme
shown in green is likely an
extremophile bacterium that lives
in a geyser
The enzyme shown in red has an
optimal temperature of 37°C, but
is denatured at 95°C and has too
little activation energy at 4 °C
Th
A.
17 Why won’t the enzyme that breaks down sucrose also
break down maltose?
A. Organisms who eat
sucrose don’t eat
maltose
B. Maltose is rare
C. The enzyme that
breaks down sucrose is
denatured at the pH
where maltose is
active
D. The substrate maltose
has the wrong shape
so can’t fit the active
site of the sucrose
digesting enzyme
h.
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Or
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25% 25% 25% 25%
18 Lactase is likely:
A. An enzyme that
digests lactose
B. A carbohydrate
found in milk
C. A protein found in
milk
D. An enzyme that
digests sucrose
...
ilk
ts
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A
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25% 25% 25% 25%
19 Which is NOT true of all enzymes?
A. All enzymes have an optimal
pH of 7 & optimal temperature
of 37°C
B. All enzymes are specific for a
particular substrate because of
the shape of the active site
C. All enzymes are re-useable
unless they become denatured
D. All enzymes can be denatured
when physical conditions are
extremely different from their
normal conditions
de
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25% 25% 25% 25%
Building Macromolecules
• Polymer – large biomolecules made by linking together a large
number of the same type of subunit
• Monomer- small molecule that is a subunit of a polymer
(building blocks)
• Chemical reactions link monomers together to build polymers or
break down polymers into monomers
– Enzymes help speed up these reactions!!
Organic Macromolecules (Polymers)
MONOMER
POLYMER
Amino Acid
Protein
Sugar
(monosaccharide)
Carbohydrate
(polysaccharide)
Nucleotide
Nucleic Acid
https://www.youtube.com/watch?v=hzFn3jH1tK0
potato catalase enzyme activity lab video—pH
https://www.youtube.com/watch?v=0nwI0xnG8W4
Enter Answer Text
En
te
rA
ns
w
er
Te
xt
100%
Polymers are large biomolecules made
of repeated subunits called
Enzymes
Sugars
Monomers
Proteins
on
om
M
Su
ga
0%
Pr
ot
ei
ns
0%
er
s
0%
rs
0%
En
zy
m
es
A.
B.
C.
D.