1. Enzymes

2. Objectives
Define Catalyst, Enzymes, Biological Catalyst
Describe how enzymes work
Describe the effect of changes in temperature an pH on enzyme activity

3. Catalyst: a substance that speeds up a chemical reaction and is not changed by the reaction
Enzymes: proteins made by organisms that speed up chemical reactions
Known as biological catalysts
Scientists say enzymes speed up, catalyze roughly 4,000 reactions in the body.

4. Enzymes have… 5 important qualities: All are proteins
Each enzyme catalyzes 1 reaction
Enzymes can be used again and again
Enzymes are influenced by temperature
work best at a particular temp
Enzymes are influenced by PH
work best at a particular pH

5. Enzymes change the substrate Into the product

6. For example: enzymes break down sugars for digestion

7. Enzyme Properties Enzymes are made inactive by high temps
As temperature increases, the enzyme activity can increase.
Too high temperature Denatures the enzyme (causes them to stop working).

8. Effect of Temperature on Enzyme Activity
As temperature
____________,
enzyme activity
can _________.
However, very high
temperatures ______
enzymes, or cause
them to stop working.

9. What is pH? pH is a measure of acidity Water has a neutral pH of 7
A change in pH can disrupt an enzyme’s shape and structure causing it to unravel, or denature.

10. Effect of pH on Enzyme Activity

11. Bellwork November 2012
Draw graph as shown on next slide and then write the correct answer, as shown in red ,under your drawing.

12. The graph shows how the rate of an enzyme-controlled reaction changes with temperature.
What is happening within “The temperature range marked “X”?
a) The enzyme is becoming denatured.”
b) The enzyme is being used up.”
c) The reaction is occurring at body temperature.”
d) The reaction is occurring at the optimum temp.”  

13. Enzymes are named for what they catalyze
Protease = breaks down Protein
Lipase = breaks down Lipids (fats)
Carbohydrase = breaks down carbohydrates
Maltase = breaks down Maltose
Sucrase = breaks down Sucrose
Amylase = breaks down Starch
What are the substrates and products?

14. Not All Enzymes Are Created Equal
Stomach enzymes work in a super acidic environment of pH 2.
A little way down the digestive tract, intestine enzymes need a pH of 8.