Enzymes

 

Enzymes are vital chemicals in all living things. They are proteins that speed up, and control, the chemical reactions inside the cells. If enzymes do not function properly, the cell or even the whole organism can die. This chapter will look at enzymes, and also some deficiency diseases, where people are born with a lack of a particular enzyme.

 

A) Web site name:  FCCJ

 

Web URL: http://web.fccj.edu/~dbyres/enzyme1.html

 

 

Read "Mechanisms of Enzyme Action"

 

1).      What are the two main roles of enzymes?

 

                 

 

2).      What is a "substrate"?

 

 

3).      In the first diagram (with sucrase), is the substrate broken apart into two products, or are two substrates joined to make a single product?

 

 

4).      What are two ways that the barrier of activation energy can be overcome?

 

 

 

5).      If the temperature of an enzyme controlled reaction increased from 10^oC to 30^oC, the reaction rate will typically:

         a) double               b) triple                c) quadruple           d) increase 9-fold

 

6).      What happens to most enzymes above 50^oC ?

 

7).      Which organisms have enzymes that can work efficiently at -2^oC ?

 

 

8).      What is the optimum pH for pepsin?

 

9).      What is inhibition?

 

                 

10).    Chemicals that are very similar to the true substrate are ________________ inhibitors.

 

11).     Why are non-competitive inhibitors unaffected by substrate concentration?

 

 

 

12).    What is a "prosthetic group"?

 

 

13).    Why does the stomach lining not get digested by pepsin?

 

 

14).    What type of reaction is done by Lyases?

 

15).    How are the following enzymes used commercially?

 

a) Substilin : __________________________________________________

 

b) Glucose oxidase : ____________________________________________

 

 

B) Web site name:  Maricopa Community College

 

Web URL: http://www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBookEnzym.html#Enzymes

 

Read "Enzymes: Organic Catalysts"

 

16).    What is a "catalyst"?

 

17).    How do catalysts lower the activation energy?

 

 

18).    Carbonic anhydrase causes chemicals to react ________ times faster than without the enzyme.

 

19).    What is the "induced fit hypothesis”?

 

 

 

20).    What are "thermolabile enzymes" ?

 

 

21).    What is the optimum pH for the enzyme Arginase?

 

22).    How does sulfanilamide kill bacteria?

 

 

23).    Which of the four competitive inhibitors shown in the diagram is the most similar in structure to succinate?

 

 

24).    What effect do the following inhibitors have?

        

         a) nerve gas: _________________________________________________

 

         b) Penicillin: _________________________________________________

 

 

Some people are born with a lack of a particular enzyme. One example of a "deficiency genetic disease" like this is called Tay-Sachs disease.

 

C) Web site name:  Center for Genetic Education, Australia

 

Web URL:  http://www.genetics.com.au/pdf/factSheets/FS35.pdf

 

Read "What is Tay-Sachs Disease?"

 

25).    Who were Tay and Sachs?

 

                 

26).    How long do children born with TSD survive?

 

27).    What is an enzyme?

 

28).    Which enzyme is missing in people with Tay-Sachs disease (TSD)?

29).    Which chromosome carries the genes for TSD?

 

30).    If both parents carry one gene for TSD, what is the chance of their child being born with TSD (affected)? _________ %

 

31).    Which population has a high risk of TSD?

 

 

32).    What test is used to find carriers of TSD?

 

 

33).    What is one option using "assisted reproductive technologies" for at-risk couples?

 

 

 

D) Web site name: The G6PD Deficiency Homepage

 

Web site address:  http://www.rialto.com/g6pd/

 

 

34).    What is the most common human enzyme deficiency?

 

 

35).    How many people are affected worldwide?

 

36).    What is one benefit of G6PD deficiency ?

 

 

37).    What food are some people with G6PD deficiency allergic to?

 

Click on "GENETICS OF G6PD DEFICIENCY"

 

38).    Why are men more likely to be affected with G6PD deficiency than women?

 

Click on figure2 to see demographics.

 

39).    In which parts of the world is G6PD deficiency most common?

 

40).    Explain why G6PD deficiency is common in these areas ( look back at Question 36 ):

 

 

 

Click the "Back" button on the top left of the screen, then click on "Molecular Biology"

 

41).    What is an "exon"?

 

42).    What is an "intron"?

 

43).    How big is G6PD compared to hemoglobin?

 

Click on "Clinical Aspects" at the bottom of the page.

 

44).    What are the two major pathologies ( diseases ) associated with G6PD deficiency?

 

 

45).    What is "neonatal jaundice"?

 

 

46).    Why does G6PD deficiency sometimes give resistance to malaria?

 

 

 

47).    Which Greek philosopher warned of the danger of eating fava beans?

 

 

48).    What is the treatment for neonatal jaundice?

 

 

49).    In which part of the world are fava beans an important part of the diet?