Section One: Activation Energy

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 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)? ______

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. ___________________________________________________________________________ ___________________________________________________________________________

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?

________________________________________________________________ 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?

____________________________________________________________________________

7. Where are some places that you use keys? ____________________________________________________________________________

8. Can two different keys pictured above open the same lock? ____________________________________________________________________________

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? ______________________________________________________________________________ ______________________________________________________________________________

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. ____________________________________________________________________________ ____________________________________________________________________________

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. ______________________________________________________________________________ ______________________________________________________________________________ 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

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. You can see above what happened to the stack of crayons after they were put through the dryer.

14. How would you describe what happened to my crayons between image A to image B? ______________________________________________________________________________

15. What caused my crayons to be changed? ______________________________________________________________________________

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.gifhttp://regentsprep.org/Regents/biology/units/homeostasis/enztemp.gif17. 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?

___________________________________________________________________________ ___________________________________________________________________________ 18. What term is used to describe when the shape of the enzyme has been altered? ____________________________________________________________________________

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.

_________________________________________________________________________ _________________________________________________________________________

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 ______________________________________________________________________________

21. Provide an explanation for why human enzymes function best at 40 C but enzymes from hot springs bacterium works best at 70 C. ______________________________________________________________________________ ______________________________________________________________________________

22. What do you think happens to the human enzyme when the temperature increases to 45 C.? ______________________________________________________________________________

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. _____________________________________________________________________ _____________________________________________________________________

27. What happens to the rate of action for this enzyme above 40°C?

____________________________________________________________________ 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. _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________

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.

_____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________

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? _____________________________________________________________________ _____________________________________________________________________

32. How can running a fever of 40°C be harmful to your health?

_____________________________________________________________________ _____________________________________________________________________

33. Instead of using medicines, suggest another method that could be used to lower body temperature.

_____________________________________________________________________ _____________________________________________________________________