Section One: Activation Energy
meters in height, BUT you know that you
have limited time because of other plans – which mountain would you choose to hike,
A or B? _______
2. If you are hiking at the same pace, which of these mountains would require MORE energy to
hike up (A or B)? ______
1. If you’re
going hiking
this weekend
and you have
the option of
hiking a
mountain
that is
1400 meters
in height and
a mountain
that is 650
Use the diagram below and your knowledge of biology to assist you in answering questions
The picture
on the
previous page
shows
someone
trying to push
a boulder up a
hill. In order
for
the boulder to reach its final destination at point B, it must be pushed to the top of the hill
because once it reaches the top of the hill it will roll down the rest of the way. A similar situation
exists with chemical reactions in living systems. Before a chemical reaction will take place,
energy must be put into the system. The energy needed for a chemical reaction to move from
point A to the top of the hill is known as activation energy. Reactions requiring less activation
energy are more likely to occur and often occur at a faster rate.
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3. Define the term activation energy.
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Comparing
the diagram
above to the
first diagram
on page one
(the heights of
2 mountains).
4. How does
the addition
of enzyme
change
activation
energy?
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5. How does the addition of an enzyme change the speed of a reaction?
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Section Two: Lock and Key Concept
Use the diagram below and your knowledge of biology to answer the following questions.
6. What are the characteristics
that distinguish one key from
another?
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7. Where are some places that you use keys?
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8. Can two different keys pictured above open the same lock?
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9. If you had to choose from the word .specific. or .general. to describe a key, which
would you choose?
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Image
modified from
http://www.edt-enzymes.com/images/pic_013.gif
10. Looking at the diagram above, how is the enzyme and substrate similar to a lock and a key?
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11. Is the chemical reaction in the diagram above a chemical digestion or a synthesis reaction?
Use at least one complete sentence to support your answer.
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12. The picture above is showing what is known in biochemistry as the .lock and key theory..
Explain why you think this theory is used to describe enzymes.
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13. What are some examples from science class or from other areas of your life where
the specific shape important for something to work correctly?
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Section Three: Factors
Influencing Enzyme Activity
You can see
above what happened to the stack of crayons after they were put through the dryer.
Last week, I was really
excited about my new
crayons, I planned on
loaning them to students
that forgot to bring a writing
tool to class. Unfortunately,
I left them in my pocket.
14. How would you describe what happened to my crayons between image A to image B?
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15. What caused my crayons to be changed?
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16. What are some other things that you have seen .melted. or change shape which impacted
their ability to work correctly. Come up with at least 2 other examples.
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Use the diagram below and your knowledge of biology to assist you in answering questions 17
through 19.
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http://regentsprep.org/Regents/biology/units/homeostasis/enzph.gif
http://regentsprep.org/Regents/biology/units/homeostasis/enztemp.gif
17. The diagram on the previous page shows what happens to an enzyme when exposed to
heat. How is this similar to what happened to my crayons?
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18. What term is used to describe when the shape of the enzyme has been altered?
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19. Predict how this change in the enzyme's shape will affect the enzyme’s ability to
function properly. Use a complete sentence to answer this question.
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Factors Influencing Enzyme Activity
pH: the optimum (best) in most living things is close to 7 (neutral).
High or low pH levels usually slow enzyme activity
Temperature: strongly influences enzyme activity
. optimum (best) 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)
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20. Using the information previously provided, identify two conditions that affect
enzyme function
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21. Provide an explanation for why human enzymes function best at 40 C but enzymes
from hot springs bacterium works best at 70 C.
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22. What do you think happens to the human enzyme when the temperature increases to 45 C.?
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23. Define the term denatured.
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Use the graph below and your knowledge of biology to answer questions 24 through 30.
24. At what
temperature is the
rate of enzyme
action highest?
________________
25. At what temperature(s) is the rate of enzyme action lowest? __________________
26. Describe the general effect of temperature change on the rate of enzyme action
from 0°C to 40°C.
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27. What happens to the rate of action for this enzyme above 40°C?
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28. Predict what would happen to the rate of action of this enzyme if the
temperature were increased from 50°C to 60°C. Support your answer.
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29. Propose an explanation for the change in rate of enzyme action between 40°C
and 45°C.
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30. Predict what would happen to our body functions if we were exposed to
frigid temperatures (below 0°C) for an extended period of time. Use the graph to
support your answer.
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Use your knowledge of biology and the information in the reading passage below to answer
questions 31 to 33.
Low grade fevers 38 to 39 C are healthy because they help our body get rid of harmful
bacteria/viruses, but when fevers reach of temperature of 105 F / 44 C degrees it is extremely
dangerous. If a person runs a fever of 40°C, it may or may not be a good idea to try to lower it
by taking medicines such as Tylenol® (acetaminophen) or Motrin® (ibuprofen).
31. How can running a fever of 40°C be helpful to your health?
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32. How can running a fever of 40°C be harmful to your health?
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33. Instead of using medicines, suggest another method that could be used
to lower body temperature.
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