Advertisement
6
Absolute Power
TIP
When using the microscope, really
sharp cutting tools are very impor-
tant. But in order to ensure that
you just cut the object of study
and not your finger, you should
prepare the razor blade appro-
priately with insulating tape or a
cork. Follow the advice on page 11
and have an adult help you.
Rice starch (top left), wheat starch (top right),
corn starch (bottom left), potato starch (bottom
right)
takes place continuously without interruption
during the day in every green plant. You might be
asking yourself now, "What? Dextrose is a sugar. And it
is supposedly produced in this process? Neither a cucumber
nor a potato nor spinach tastes sweet! So where did all the
dextrose go?" Did the plant perhaps already use it all up?
Starch — Power from Plants
Even if a plant is constantly feeding on its self-made dextrose, there is still plenty
left over in the plant — it's just in another form. Plants store their dextrose in the
form of starch. To do this, lots and lots of sugar parts are simply joined together
in a long, winding chain. And starches don't taste sweet. You can test this out
simply enough by trying some flour. Flour is practically nothing more than starch.
Depending on what plant the flour came from, it can also be referred to as wheat,
corn, or potato starch.
You can perform a simple test for what foods still contain starch using iodine solu-
tion. Iodine and starch result in a deep blue coloring. If a lot of starch is present,
such as in flour or in potatoes, then the color is so intense that it looks almost
black. You should not eat the food after the test. Starch is stored in plant cells in
the form of so-called starch granules. These are large clusters of starch chains. The
starch granules will look different depending on what plant the starch is from.
Starch in All Forms
It's quite easy to study the various forms of starch granules under the micro-
scope. You will need:
• slide and a cover slip
• the pipette and water
• a razor blade (see page 11)
• the dissecting needle
• the tweezers
• iodine solution (see tip on this page)
• starch-containing foods, e.g. potatoes, various types of flour, grains, garden
beans, and so on
• a beaker
22
After every breath, you exhale carbon dioxide.
Anytime anything is burned, regardless of
whether it is gas inside an automobile mo-
tor or grilled hot dogs, this colorless gas is
produced. Perhaps you've already heard
carbon dioxide referred to as a green-
house gas. Together with other gases, it
is likely responsible for the heating-up of
the Earth's atmosphere — like in a green-
house. For plants, however, this carbon
dioxide is a substance that is essential to
their survival. They use it together with
water and sunlight to produce dextrose (see
also "Life in a Shoebox," page 15). This process
Advertisement
