Biol 12:
Proteins, Enzymes, and Metabolism
Review Package
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A. Proteins:
1.
are proteins that control chemical reactions.
2. Amino acids are the monomers for a
. An amino acid
consists of three groups; an amino group, an
group and
the R group, because it is the Remainder of the molecule. Amino acids differ from one
another by their
group.
3. A bond that joins two amino acids is called a
bond .
A
is a single chain of amino acids.
4. The
structure is the linear sequence of the amino acids joined
by peptide bonds. The
structure of a protein comes about
when the polypeptide takes on a particular orientation in space. The
structure of a polypeptide is its final three-dimensional shape. Separate polypeptides are
arranged to give some proteins a fourth level of structure, termed the
structure, such as hemoglobin.
5. When proteins are exposed to extremes in heat and pH, they undergo an irreversible
change in shape called
.
6. The peptide bond is a type of reaction called
where a water molecule is
to 2 monomers (in this case, they are
)
and they become “spliced” together. The reverse reaction is called
reaction, a water molecule is
monomers.
. In this
to break the bond between two
Proteins, Enzymes, and Metabolism
Review Package
Biol 12:
7. Utilize the following terms to label the diagram below: dehydration synthesis, H2O,
disaccharide, and monosaccharide, hydrolysis.
8. Match the following answers for proteins to one of the statements below.
a. enzymes
b. R Group
c. polypeptide
d. amino acids
e. secondary structure
f. tertiary structure
protein’s final three-dimensional shape
accounts for differences in amino acids
a single chain of amino acids
alpha helix of a polypeptide strand
monomer subunits of a protein
proteins that speed up chemical reactions
B. Energy and Enzymes:
1. Entropy is a measure of
form of energy has
or disorder. An organized, usable
entropy, whereas an unorganized, non-usable form
of energy such as heat has
entropy. Energy conversions
eventually result in
, and therefore the entropy of the
universe is always
.
2.
occurs when the energy released by an exergonic
reactions is used to drive an endergonic reaction. What molecule is often coupled to
cellular reactions that require an input of energy?
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Biol 12:
Proteins, Enzymes, and Metabolism
Review Package
3. A metabolic
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begins with a particular reactant, terminates
with an end product, and has many minute steps in between. A
is a substance that participates in a reaction. A
is a
substance that is formed by the reaction. The reactants in an enzymatic reaction are
called the
for that enzyme.
4. An
is a protein molecule that functions as an organic catalyst
to speed up a chemical reaction.
5. The energy that must be added to cause molecules to react with on another is called
the
. Enzymes
the amount of energy for activation to occur.
6. When an enzyme forms a complex with its substrate, the small part of the enzyme
that complexes with the substrate is called the
In the
model, the active site
undergoes a slight change ins shape in order to accommodated the substrate. Only a
small amount of enzyme is actually needed in a cell because enzymes are not
.
7. Enzymes are very
their
in their action and are named for
.
8. As the temperature rises, why is there an increase in enzyme activity?
9. When an enzyme’s shape changes due to high temperature or extreme pH, the
enzyme is said to be
10. In
.
inhibition, a product produced in high
amounts by an enzymatic reaction can inhibit the enzyme’s activity. The end product of
an enzymatic pathway binds at an allosteric site on the
enzyme of the pathway.
Biol 12:
Proteins, Enzymes, and Metabolism
Review Package
11. In
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inhibition, another molecule is so close in
shape to the enzyme'’ substrate that it can compete with the true substrate for the
enzyme’s active site. In
inhibition, a molecule binds to an
enzyme, but not at the active site. This other site is called the
site and causes a shift in the three-dimensional structure.
12.
are organic molecules that bind to enzymes and
serve as
for chemical groups or electrons.
are small organic molecules that are required in
trace amounts in our diet for the synthesis of coenzymes.
13. Consider the following reactions and answer the question below.
a. A + B  C + D + Energy
b. Energy + C + D  A + B
c. A + B  C + D
Reaction
is considered endergonic, whereas reaction
is considered
exergonic. In reaction (a) above, the products C and D have
(more/less)
energy than the reactants A and B. In reaction (b) above, the products A and B have
(more/less) energy than the reactants C and D. Reaction
is at equilibrium. In
order to make reaction c go to the right, one of the products could be used as a
in another reaction.
14. Use the following terms to label this diagram: substrate, enzyme, active site,
enzyme-substrate complex, product.
15. Consider this metabolic pathway:
A-E1 B-E2 C-E3 D
Proteins, Enzymes, and Metabolism
Review Package
Biol 12:
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If E1 - E3 represents different enzymes, letters A,B,C are considered
or substrates in the reactions, whereas letters B, C, and D would be considered
. As a result of the action of E2,, B is now
called a
for E2, and C is the product.
16. When the substrate binds to the enzyme, the enzyme undergoes a slight alteration in
shape to achieve optimum fit. This concept is termed the
model.
17. For each of the following characteristics of enzymes, put T for true or F for false.
Each reaction in a cell uses a specific enzyme
Slows down chemical reactions
Named for their substrates
Enzymes and products form a complex
Substrate binds to enzyme at active site
Increase in temperature causes decreased activity
Each enzyme has an optimal temperature
All enzymes have the same optimal pH
18. The thyroid gland releases a hormone called
which
acts on cells, causing them to
If iodine is lacking in the diet, the thyroid gland enlarges, producing a
As a result, when there are low levels of thyroxin in the blood, called
, no negative feedback occurs, and the anteriaor
pituitary continues to produce
(
),
which stimulates the thyroid to hypertrophy.
19. Thyroxin increases the
broken down.
rate in which glucose is
Biol 12:
Proteins, Enzymes, and Metabolism
Review Package
20. Describe the process that controls the release of thyroxin from the thyroid gland.
(including the hypothalmus) ?What is this process called?
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