Energy Practice problems
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1
Energy Transfer i n an Ecosystem
Bird
Frog
Part A - Answer the questions using the diagram to the right %>
1. How many food chains make up tiie food web?
2. Which organism is an herbivore?
3. Which organism is an autotroph?
4. Which organism is an omnivore?
5. Which organism is a tertiary consumer?
6. Finish the web: Draw in arrows showing how the organisms on
the diagram relate to the decomposer. Summarize your answer.
Decomposer
Part B - Use the food web below to fill i n the table. List all organisms as autotrophs or heterotrophs i n the
first two columns. In the third columns, state whether each heterotroph is a primary, secondary, or tertiary
consumer. [Note: If an organism fits into more than one category, list only the highest order.
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Heterotrophs
Autotrophs
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Type of Heterotroph
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Chemical Reactions
1. During a chemical reaction, bonds are
2. Protein catalysts, or enzymes, act by lowering the
required for a reaction.
3. The reactants (starting molecules) of an enzyme-catalyzed reaction are known as
According to the induced fit hypothesis of enzyme catalysis,
.
a. the binding of the substrate depends on the shape of the active site
b. some enzymes change their structure when activators bind to the enzyme
c. the binding of the substrate changes the shape of the enzyme's active site
d. the active site creates a microenvironment ideal for the reaction
5. In the figure below, why does the reaction rate
plateau at higher reactant concentrations?
Rate of an enzyme-catalyzed reaction.
(Note: enzyme concentration is constant.)
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7. Why are two pathways shown in graph LT? What does Une C represent?
The following questions are based on the reactionjA + B r^C + D shown i n the accompanying figure.
and the products are (A, B. C or D)
8. In this reaction, the substrates are (A, B, C or D)
9. Which has a higher free energy, the substrates or the products?
a. Is this reaction endergonic or exergonic?
Match the arrow on the diagram to the concept it represents. Which arrow represents the ...
10. Activation energy required when no enzymes are present?
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11. Activation energy required for the enzyme-catalyzed reaction in the figure? fo
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12. Total energy given off during the reaction?
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13. Which arrow in the figure would be the same in an enzyme-catalyzed and a non-catalyzed reaction?
The graph below shows enzyme activity at varying
temperatures.
X = opifrnal temperature
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14. Describe what is meant by optimal temperature for
enzyme activity.
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15. Explain why most enzymes perform poorly at low
temperatures.
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The graph below shows enzyme activity at varying pH
levels.
16. State the optimum pH for each of the enzymes:
Pepsin:
Trypsin:
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Amylase:
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17. Pepsin acts on proteins in the stomach. Explain
how its optimum pH is suited to its working
environment.
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18. The diagram below shows the structure of
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ATP.
• OH OH
a. Label the high-energy bonds.
b.
Circle the portion of the molecule that makes up ADP.
c.
ATP is a derivative of which type of monomer?
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19. How does ATP enable the cell to store and transfer energy?
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20. In which cellular organelle is ATP produced? i" - * \ij CJMJ
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a. What is the name of the process by which ATP is produced? CXXM,4AX§S/"''
R
it-out pages: Paste these pictures into your notebook along with your homework objectives,
jjective 1:
a
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light
energy
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photosynthesis
CO^i + H , 0
sn chlorop lasts
sugars ^ Q
2
- . cellular respiration
m mitochondria
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ATP powers most cellular work
heat
energy <tf
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