Lab Report: Enzyme Lab
Purpose of this Lab
What is the goal of this lab? What question is it trying to answer, or what problem is
it trying to explain?
It is going to explain how a liver’s enzymes break down substances that could be harmful.
Hypothesis
After reading the lab instructions - but before starting the lab - record your best
“educated guess” about what will happen in the experiment. Give your reasons and
outline any assumptions that lead you to this hypothesis.
Catalase from liver will catalyze the reaction of hydrogen peroxide to produce molecular oxygen and water.
Furthermore will catalase not be used in the reaction, but be able to continuous carry out the reaction, as it
is characteristic for enzymes.
Experimental Design
List the materials used in this lab, and the procedure you followed.
Materials:
1. Commercially available bottle of hydrogen peroxide, from drugstore
2. Liver, either chicken or beef
3. An onion
4. A small potato
5. An Apple (peeled)
6. Wooden sticks (can be the ones used for shish kebobs)
7. Matches
8. Sharpie marker pen or other pen that can write on a glass surface
9. Tap water
10. Several glass kitchen glasses (so you can observe the inside of the glass)
Procedure (list steps in the order in which you performed them):
1.
2.
3.
Cut two small (1/4 to 1/2 inch long) pieces of liver.
Place the liver into two small glasses, labeled “C” and “E”.
Pour enough hydrogen peroxide from the bottle to cover the liver in glass “E”, add a little more. Pour
the same amount of water into tube “C”.
4.
5.
6.
7.
8.
9.
A simple test for the presence of hydrogen gas is to hold a glowing wooden applicator stick at the
mouth of the test tube or in the bubbles forming at the surface of the liquid. Hydrogen gas produces a
popping sound.
A simple test for the presence of oxygen is to hold a glowing applicator stick in one or more of the
bubbles inside the tube. If oxygen is present, the glowing end of the stick will fare up and glow
brighter.
Light a match and burn the end of one of the wooden sticks. The stick should catch fire.
Allow the stick to burn for a few seconds, and then blow out the flame, leaving a glowing tip.
Perform the test described above. Since enzymes are not supposed to be used up, extract the piece of
liver from the glass and add it to a second glass to which you then add more hydrogen peroxide.
Pour the liquid from the first glass into a third glass containing fresh hydrogen peroxide.
Data
Record the data you collected in the lab
Observations:
3. What happened in test tubes C and E? They became fizzy with water/oxygen foam.
What was the purpose of the water in tube C? It’s the negative control.
4. Test for the presence of hydrogen gas and oxygen gas.
Which gas, oxygen or hydrogen, was produced by the reaction? The hydrogen made the stick pop and the
oxygen made the glowing end flare up.
5. Since enzymes are not supposed to be used up, extract the piece of liver from the glass and add it to a
second glass to which you then add more hydrogen peroxide.
Notebook activity:
What happened in the second tube? It fizzed a little bit.
6. Pour the liquid from the first glass into a third glass containing fresh hydrogen peroxide.
Notebook activity:
Was there a reaction? Yes Explain There was a reaction as it was observed molecular oxygen was being
produced from the oxygen test as it was observed the stick flared up.
How might you test for the presence of the enzyme in some common materials such as apples, potatoes,
and onions? Design and record ONE test you have performed in the Enzyme Observation form (see below)
to detect the presence of catalase in ONE food item.
Do the same experiment you did for the liver but replace the liver with an apple, onion or potato. I did an
experiment for a potato. Cut the potato and put one piece in hydrogen peroxide and another in water. I
concluded with the same results I got for liver.
Analysis
Analyze the data you collected in the lab
Characterization of the reaction carried out in the liver:
C
O2
-
E
+
H2
-
The results indicated that hydrogen peroxide was made into molecular oxygen. The results also indicate
that there was no hydrogen production from the reaction.
Regeneration and Preservation of Catalytic Effect:
From the E sample there were, removed a part of the liver into a new tube, and added hydrogen peroxide
and an observation for oxygen and hydrogen were done. The results from the experiment was that even if
you run the reaction in excess hydrogen peroxide, the reaction can still produce molecular oxygen if you
add further hydrogen peroxide.
Conclusion
After conducting the experiment, how would you now explain the problem(s) or
answer the question(s) raised when you described the purpose of the lab? Be sure
to base your answer on the data you collected
From the analysis I should be able to check the following things:
It was observed that hydrogen peroxide in the in the presence of catalase, is able to produce oxygen, with
an easy observable rate as the solution became fizzy. In order to investigate that it was indeed an enzyme
catalyzing the reaction, there was tested for characteristic ability of enzymes, not being used during the
reaction. The results showed that even if you run the reaction a first time with excess hydrogen peroxide,
and run the reaction again with excess hydrogen peroxide, the reaction still occurs
It is there for concluded that catalase work as an enzyme and catalyzes the reaction
catalase 1
H2O2 (aq) →
2
O2 (g) + H2O (l)
Notebook Activity:
What does an antioxidant do for the human body? Use the Internet or a book to
answer this.
Antioxidants are chemicals (both naturally occurring and man-made) that can
prevent or slow cell damage. An “antioxidant” is actually not a substance; it’s a
behavior. Any compound that can donate electrons and counteract free
radicals has antioxidant properties.
Natural antioxidants are mainly found in fruits and vegetables, marine plants, and
some seafood that eat marine plants. There are thousands of antioxidant
compounds out there, but the most common dietary ones are vitamins A, C, and E,
beta-carotene, and lycopene. Antioxidants can also be produced artificially and
consumed in supplement form.
What Are Free Radicals?
Exposure to oxygen (aka oxidation) can “break” atoms, so they end up with
unpaired electrons, which make them chemical loose cannons. These bad boys,
called free radicals, are constantly on the hunt for spare electrons to stabilize their
mixed-up atoms. Free radicals latch onto electrons from other cells, which can
create a chain reaction of free radical-ness. Stealing nearby electrons means that the
cell next door loses some of its electrons, therefore becoming a free radical in its
own right. Sounds tiring.
Why Are Free Radicals a Bummer?
It’s rarely a good idea to mess with cell structure, and it can get gnarly when the
cells undergoing oxidative stress contain DNA [1]. Oxidative stress has been linked
to serious diseases like cancer, heart disease, stroke, aging, diabetes, arthritis,
fibromyalgia, Parkinson’s Disease, Alzheimer’s, autoimmune diseases, cognitive
decline, and eye conditions like macular degeneration [2].
What Do Antioxidants Do?
If the human body were a baseball game, antioxidants would be the first baseman.
Antioxidants are one of the first lines of defense that the body employs to keep free
radicals in check and prevent them from causing a domino effect of damage on other
cells. Antioxidant compounds can “donate” electrons to unstable free radicals so
they don’t have to snatch electrons from unsuspecting nearby cells. Antioxidants can
also help repair cell damage caused by free radicals.
What’s the Catch?
As is often the case with health buzzwords, antioxidants aren’t all they’re cracked up
to be. There’s very little actual scientific proof that antioxidants are the magic
bullet to protect us from heart disease, stroke, and cancer.
In fact, some studies have shown that consuming extra beta-carotene can actually
increase risk of lung cancer in smokers. Several randomized trials have confirmed
that cancer patients who took antioxidants supplements during their treatments
actually had worse outcomes. In one randomized trial, women who took antioxidant
supplements had higher rates of skin cancer than those who didn’t.
Studies involving heart disease and strokes show that antioxidants (even when used
in various combinations) have a largely placebo effect (the only exception is vitamin
E, which significantly benefited women with cardiovascular disease) [3] [4].
Also, recent research has disproven the idea that all free radicals are inherently bad
for health. The body actually requires a certain amount of these infamous
compounds to kill cancer cells and bacteria, among other tasks. Overloading on
antioxidant supplements can disrupt these beneficial free radical behaviors, leading
to disease or illness.
While we don’t know exactly how dietary antioxidants affect disease, a healthy
diet with plenty of antioxidant-rich fruits, vegetables, and grains is always
beneficial.
Work Cited
Sophia Breene. What are Antioxidants (and How Do They Work). Web. 16 Dec. 2013. <
<http://www.greatist.com/health/what-are-antioxidants>
Complete this equation. H2O2 -----------------------> 1/2 O2 (gas) + H2O
Enzyme Observation Form: Observation:
Hypothesis: Catalase from liver will catalyze the reaction of hydrogen peroxide to
produce molecular oxygen and water. Furthermore will catalase not be used in the
reaction, but be able to continuous carry out the reaction, as it is characteristic for
enzymes.
Experiment: Put a piece of liver in hydrogen peroxide.
Data: A reaction occurs. Bubbles start to form.
Conclusions: The results showed that even if you run the reaction a first time with
excess hydrogen peroxide, and run the reaction again with excess hydrogen
peroxide, the reaction still occurs
Notes: In the experiment oxygen was formed.
Notebook activity:
What is hydrogen peroxide used for around the house?
Hydrogen peroxide is the only germicidal agent composed only of water and oxygen.
Like ozone, it kills disease organisms by oxidation! Hydrogen peroxide is considered
the worlds safest all natural effective sanitizer. It kills microorganisms by oxidizing
them, which can be best described as a controlled burning process. When Hydrogen
peroxide reacts with organic material it breaks down into oxygen and water. Here
are some of the uses of hydrogen peroxide:
1. Hydrogen Peroxide is useful to prevent infections by destroying harmful germs &
bacteria.
2. Clean Your Wooden Cutting Board. An improperly cleaned cutting board is a
breeding ground for bacteria. Clean it thoroughly, without harsh chemicals, with
hydrogen peroxide and vinegar.
3. Grow Mushrooms in the Fridge. It’s true! With the help of hydrogen peroxide,
you can grow oyster mushrooms in a freezer bag in your fridge. For detailed
instructions, click here.
4. Make Sure Your Veggies are Safe. Nobody wants bacteria-filled vegetables.
Place 3% hydrogen peroxide into a spray bottle and mist over your produce,
letting it soak for about five minutes before rinsing off and drying.
5. Clean Sponges. Just can’t seem to get that funky smell out of your sponges?
Combine equal parts hydrogen peroxide and warm water in a shallow bowl, and
let the sponge soak for about 15 minutes before rinsing thoroughly.
Explain its use and action in view of the activities in this lab: The hydrogen peroxide
is used as a substrate for a catalyst. This catalyst is an enzyme, which breaks down
harmful hydrogen peroxide into harmless substances (water and oxygen).