Chemical Reactions and Enzymes Worksheet
NAME:
Catalase and Hydrogen Peroxide
Hydrogen Peroxide (H2O2) is a mild acid that is produced in our bodies through natural process that benefit us by fighting
infections and optimizing overall cellular health. However, high concentrations of H2O2 is lethal so bodies must manage
this substance. Catalase is a natural enzyme that does just this. Performed in various regions such as in the liver,
catalase breaks down 2 H2O2 into 2 water (H2O) and one oxygen (O2).
1. Write a chemical reaction that summarizes this reaction.
2 H2O2 + 2 water  2H2O + O2
2. Describe how this illustrates the concept of the conservation of matter.
3.
THE NUMBER OF ATOMS ON THE LEFT SIDE (4 HYDROGEN AND 4 OXYGEN) EQUALS THE NUMBER
OF ATOMS ON THE RIGHT.
In optimal conditions, hydrogen peroxide is broken down into water and oxygen, illustrated in the graph below. Some
serious conditions can alter catalase’s activity, such as pH and temperature.
4. What does the line
given represent?
THE LINE REPRESENTS
PRODUCTIVITY UNDER
IDEAL CONDITIONS.
5. In a different color,
draw in and label a
new line that would
represent this
reaction’s production
if temperature is
increased by 5°F
(about 2.5°C).
6. Justify this.
INCREASING BY A LITTLE
WON’T DESTROY THE
ENZYME, BUT WILL
DECREASE ITS
PRODUCTIVITY
7. In a different color,
draw in and label a
new line that would
represent this reactions production if temperature is
boiled (denatured).
8. Justify this.
A DENATURED PROTEIN WILL NOT FUNCTION. NO
FUNCTION MEANS NO PRODUCTIVITY BECAUSE THE
DENATURED PROTEIN HAS NO EFFECTIVE ACTIVE
SITE. THE SUBSTATE REACTANTS WILL NOT BIND TO
THE ENZYME, THEREFORE, WILL NOT BIND WITH
OTHER SUBSTATE REACTANTS AND FORM NO
PRODUCTS.
Soap and Dirt
Dirt, generally considered non-polar, sticks to the body either by becoming trapped in microscopic wrinkles in the skin or,
if the dirt is moist, by adhering (sticking) to the natural oils of our skin. Sometimes the natural oils on skin will give the dirt
an oily coating. In such cases, water alone will not remove the dirt, but soap and water will. Use the information below and
your understanding of polarity and chemical reactions
to answer the following questions.
a. A soap molecule is long, with one non-polar
end attracted to non-polar oil molecules and
the other polar end attracted to polar water
molecules.
b. Soap will dissolve and will float freely in water
if there is no dirt or oil.
c. Soap is attracted to and will bind with oil
particles (sometimes where dirt is trapped).
d. The product of soap molecules and oils are
micelles (pictured below).
Read each question, and write your answer
in the space provided.
1. What is the difference between polar and
non-polar?
POLAR = MOLECULE HAS AN UNEVEN
DISTRIBUTION OF CHARGE ACROSS THE WHOLE OF TH MOLECULE
NON-POLAR = MOLECULE HAS A (relatively) EVEN DISTRIBUTION OF CHARGE ACROSS THE
ENTIRETY OF THE MOLECULE
2. Why does soap dissolve in water? (like when you put detergent into the sink water)
SOAP WILL DISSOLVE IN WATER BECAUSE OF THE PART OF THE SOAP MOLECULE THAT IS POLAR
WILL INTERACT WITH OTHER POLAR MOLECULES, LIKE WATER.
3. Why does dirt stick to soap, but not to water?
DIRT (NONPOLAR) WILL STICK TO THE NONPOLAR REGIONS OF A SOAP MOLECULE, HOWEVER
WATER HAS NO NONPOLAR REGION SO THE DIRT WILL AVOID WATER.
4. Write what you believe would be the chemical reaction of soap and oil in the correct form.
SOAP + OIL  MICELLE
5. How does dirt and soap come into contact with each other?
RANDOMLY, THE SOAP’S NONPOLAR REGION WILL STICK TO THE NONPOLAR DIRT PARTICLES AS
IT’S DISSOLVING IN WATER.
6. What are two ways you could improve the activity of soap in any “cleaning” situation?
SIMPLY PUT, ADD ENERGY BY EITHER HEATING THE WATER OR SCRUBBING (BOTH OF WHICH WE
LEARN PRETTY EARLY ON… WASHING IN WARM/HOT WATER OR SCRUBBING WITH SOMETHING
ABRASIVE (adding friction) WORKS BETTER THAN WASHING IN COLD WATER)
Pepsin and Trypsin in Digestion
The graph shows the rate of enzyme activity in relation to pH for
two enzymes—pepsin and trypsin. Both enzymes break down
molecules in food taken into the human body, but the enzymes
act in series, meaning one after the other. Pepsin breaks some
bonds in very large macromolecules forming fragments. Trypsin
then acts on the fragments produced by the action of pepsin,
breaking them into even smaller units. Once the fragments are
small enough they will be absorbed into the blood stream and
finally into cells. Use the graph to answer
following questions.
Read each question, and write your answer in the
space provided.
1. Write 2 different chemical reactions that would best
summarize the two major reactions taking place in
this scenario.
PEPSIN + LARGE MOLECULE  FRAGMENTS
TRYPSIN + FRAGMENTS  SMALLER UNITS (implied that these units can be absorbed by our cells)
2. The liquid in the stomach has a pH of about 2. Which of the two enzymes would be active in the
stomach?
PEPSIN
3. The liquid in the small intestine has a pH of about 8. Which of the two enzymes would be active in the
small intestine?
TRYPSIN
4. What must happen to the liquid as it passes from the stomach to the small intestine for digestion to
occur normally?
THE pH MUST BE INCREASED SOMEHOW
5. Consider the data on the relationship between pH and enzyme activity shown in the graph. Do
enzymes typically function only at a specific pH, or can they function within a range of pH values?
THEY FUNCTION IN A RANGE OF pHs THOUGH THERE IS AN OPTIMAL pH FOR EACH (INDICATIVE OF
THE HIGHEST RATE OF REACTION)
6. Can pepsin and trypsin function in the same environment? Explain.
THEY CAN BUT BOTH WOULD FUNCTION AT LESS THAN OPTIMAL LEVELS. THE pH WOULD BE
BETWEEN 4 AND 5 IN THIS CASE. THIS IS OF COURSE LESS THAN OPTIMAL FOR EITHER ENZYME.