Question of the Day

1
Question of the Day

• What does an enzyme do?
• An enzyme speeds up the reactions that break down
  food
• What is a denatured enzyme?
• An enzyme that does not work correctly

2
Objective

• By the end of class today, you will be able to
• Explain how an enzyme functions
• Describe the factors that affect enzymes

3
Lactase Lab Data
Test Tube Test Solution Predicted glucose Initial glucose Final glucose
A Milk and Enzyme
B Milk and Water
C Milk and Denatured Enzyme
D Sucrose and Enzyme
500 mg/dL
Your Answer Here
100 mg/dL
100 mg/dL
100 mg/dL
Your Answer Here
Your Answer Here
Negative
Negative
Your Answer Here
Negative
Negative
4
Lab Analysis Questions

• 1. What are the two monosaccharides that comprise
  a molecule of lactose?
• Galactose and Glucose

5
Lab Analysis Questions

• 2. What are the two monosaccharides that comprise
  a molecule of sucrose?
• Glucose and Fructose

6
Lab Analysis Questions

•  3. How does the lactase enzyme function in our
  digestive system?
• The lactase enzyme attaches to the disaccharide
  lactose and breaks it apart
• This gives our body access to glucose (simple
  sugar)

7
How does an enzyme function?
8
Lab Analysis Questions

• 4. Does an enzyme make a reaction happen that
  wouldnt occur naturally?
• No, an enzyme cant magically make a reaction
  happen
• Instead, an enzyme speeds up a reaction that
  would normally occur

9
Lab Analysis Questions

• 5. What does denatured mean, and what does a
  denatured enzyme do?
• Denatured means that it doesnt work like it
  should
• De opposite of natured natural
• A denatured enzyme does not break down the food
  that it should
• Look at the data table

10
Lab Analysis Questions

• 6. What does it mean to be lactose intolerant?
• People with lactose intolerance are unable to
  break down the sugar that is in dairy products
• This means that they feel sick to their stomach
  when they eat/drink dairy products like milk

11
What factors affect enzymes?

• pH
• Temperature
• Substrate concentration
• Inhibitors

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pH

• All enzymes have an optimum pH
• This means that they only work at certain places
  in the human body
• Saliva has an optimum pH of 7 and is found in the
  mouth
• Pepsin has an optimum pH of 2 and is found in the
  stomach
• Lactase has an optimum pH 6.5 and is found in the
  small intestine

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What does this indicate about our digestive
system?

• pH 7
• pH 2
• pH 6.5

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pH

• When an enzyme is placed in an pH too far from
  its optimum range it gets denatured

15
Temperature

• For our lab, I boiled the enzyme for ½ an hour
• What do you think this did to the enzyme?
• It denatured the enzyme
• What do you think would happen if I froze the
  enzyme for ½ an hour?
• It would have denatured the enzyme

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Substrate Concentration

• Concentration means the amount of a substance in
  a given area
• Class as model
• Three volunteers to be enzymes (lactase)
• Volunteers to be substrates (lactose)

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Inhibitors

• Competitive
• Bind to the active site and prevent substrate
  from binding
• Occupy the active site
• Draw example of lactase and galactose
• Non-competitive
• Bind somewhere other than the active site
• Change the shape of the active site
• Model with hands

18
Objective

• By the end of class today, you will be able to
• Explain how an enzyme functions
• Describe the factors that affect enzymes