s
t
ep Living things are made of many
nc simple and complex molecules.
Co Chemical reactions in living things are
necessary for survival.
W
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acid - a compound that increases the number of
hydrogen ions (H+) in solution with water. All
acids have a pH below 7.
amino acid - a small molecule that is a building block
of a protein; long chains of these make proteins.
atom - a very, very small particle that makes up all
matter.
base - a compound that decreases the number of
hydrogen ions (H+) in solution with water. All
bases have a pH above 7.
biochemistry - the study of chemical reactions
that occur within living things.
carbohydrate - a complex molecule made of many
sugars.
catalyst - a substance that helps chemical
reactions occur but is not changed in the
reaction.
chemical reaction - an interaction of atoms or
molecules to form new elements or molecules.
enzyme - a protein that acts as a catalyst.
DNA - DeoxyriboNucleic Acid; this complex molecule
carries genetic instructions for living things.
indicator - a chemical that changes color with
changes in pH.
matter - a group of at least two atoms held
together in a definite arrangement.
molecule - a small particle made of two or more
connected atoms.
pH - a scale that measures relative acidity and
basicity.
protein - a complex biological molecule that may
act as a structural element or may assist
biochemical reactions; hair, nails, skin, muscle are
all proteins.
sugar - simple biological molecule that provide
energy for living things.
© 2007 OMSI
Use the
Words to Know
to complete the puzzle below.
Down
1. Cabbage juice, an _____, turns deep red in acidic
solutions.
2. A _____ helps a chemical reaction to occur but is
not changed during the reaction.
3. An enzyme is a special type of _____.
4. Pasta, crackers, popcorn, and bread are all
examples of a _____.
Across
5. _____ carries genetic instructions in all living
things.
6. _____ is the study of the chemical reactions of
living things.
7. Vinegar is an acid since its _____ is below 7
CheM LaB
Take-Home Activities
Biochemistry
To do and notice:
Days 1-2
Put the eggs in a jar. Cover the eggs with vinegar. Keep the
eggs in vinegar for two days. Look for
changes on the surface of the egg during the
two days. As the egg shell reacts with the
vinegar, the reaction produces carbon dioxide
gas bubbles.
• What happens to the shells?
To do and notice:
1. Half fill the bottle with warm water.
• Why might hot or cold water not work?
© 2007 OMSI
Yeast use sugar as food. In a biochemical
reaction called “fermentation,” the yeast breaks down
the sugar (C12H22O11) into ethyl alcohol (C2H5OH) and
carbon dioxide gas (CO2). The carbon dioxide gas creates
the foam and inflates the balloon. Brewers and bakers
both use this reaction. Brewers use yeast to create
bubbly alcohol. Bakers use yeast to make bread rise.
Yeast are tiny organisms that live well at warm
temperatures. The yeast will die in water that is too hot
and will not be active in water that is too cold.
A closer look:
5. Sit back and watch. After
about 20 minutes you should
see the balloon begin to inflate.
This process will continue over
the course of several hours.
• Why does the balloon inflate?
4. Uncap the bottle and stretch
the neck of the balloon over
the bottle opening for a tight
seal.
3. Cap the bottle tightly and
shake it well.
The membrane around the egg is like a very fine mesh.
Small molecules like gases and water can pass through the
membrane, but larger molecules like proteins or sugars
cannot. When water passes through the membrane, this is
called “osmosis.”
Corn syrup is a very concentrated solution of large
molecules. When the egg is in corn syrup, water from inside
the egg flows out to dilute the corn syrup. The egg shrivels.
In water, solution inside the egg is more concentrated than
the water outside. The water flows into the egg in an
attempt to dilute the white of the egg. This makes the egg
swell up to its full size.
A closer look:
Day 4
Observe both eggs (you can gently pick them up).
• What are the differences between them?
Put one egg in each jar. Cover one egg
with water and cover the other egg with
light corn syrup. Let the eggs sit
overnight.
Day 3
Carefully remove each egg from the
vinegar. Rinse the eggs and the jars with
water. Gently feel the eggs.
2 raw eggs in their shells
vinegar
corn syrup
water
one small clear plastic soda bottle
warm water
one package active yeast
2 tablespoons sugar
2. Add the yeast and sugar to the bottle.
Materials:
Materials:
large bowl
spoon
plastic cups
baking soda
vinegar
Red cabbage contains a chemical that changes its
shape depending on whether it is surrounded by an acid or
base. When its shape changes, so does its color. The
cabbage juice is purple in water (neutral), red in vinegar
(acid), and blue-green in baking soda (base).
Some other plants also have chemicals that change
color. Try this with flower petals, juices, or berries.
A closer look:
7. Find other things to add to the cabbage juice. Examples
might include milk, lemon juice, soda water, soap,
antacids, and aspirin.
6. Add some baking soda to another of the cups.
• Is the color different?
5. Use the spoon to put
cabbage juice in some
plastic cups. Add a few
drops of vinegar to one of
the cups.
• What color is the mixture?
4. Place the strainer in the bowl. Pour the cabbage pieces
and cabbage juice through
the strainer, collecting the
juice in the bowl.
3. Place the cabbage pieces in the pot and cover them with
the hot water. Let the cabbage pieces sit for 2 minutes
in the hot water.
• What happens to the color of the water?
2. With an adult’s help, chop the cabbage with a knife or
food processor.
1. With an adult’s help, heat the pot of water until the
water is very hot.
To do and notice:
large pot half full of water
water
½ head of RED cabbage
chopping knife or food processor
strainer
Materials:
Test the pH of household products!
A four-day eggsperience!
Can biochemistry blow up a balloon?
CAUTION: Always wash
your hands thoroughly
with soap after handling
raw eggs, which are a
common source of
salmonella bacteria.
Cabbage Juice Indicator
Egg Osmosis
Yeast Balloons