H
HO
R1
H
N N CC CC
HO
R2 H
NCC
HO
Rm H
N
H
CC
H
+H2O
PEPSIN
O
Rm+1
N
H
CC
HO
Rm+ 2
CC
HO
Rn–1
N
H
CC
OH
O
H
Rn
N
H
CC
HO
Rm+ 2
CC
HO
Rn–1
N
H
CC
OH
O
Rn
N
H
H
HO
R1
H
N N CC CC
HO
R2 H
NCC
HO
Rm H
N
H
C+
H
Rm+1
C
OH
OH
H
N
PEPTIDE BOND
R
S
GR
AP
HX
,
IN
C.
;
S
HU
TTE
RS
TO
CK
Figure 2. When a protein undergoes a hydrolysis reaction, it is broken down into two smaller molecules. These smaller molecules are later broken down further
into the basic building blocks of a protein, called amino acids. The protein molecule is shown here as a linear molecule for simplification (it is not actually
linear but has a complicated 3-D shape) to illustrate how the hydrolysis reaction works.
that contains genetically engineered ingredients
and in conventionally grown crops.
Potential risks
As stated above, a small but vocal group
of people claims that genetically engineered
crops are harmful to human health, for
example by introducing new allergens. Some
activists have reportedly destroyed test plots
of plants, wasting millions of dollars and
countless hours of research. However, scientists have refuted these claims. In 2016, the
National Academies of Sciences,
Engineering, and Medicine
released a report concluding that
eating genetically modified food
is no riskier than eating conventionally grown crops—after all, many
known allergens in the food supply were identified long before GMOs were created. Also,
testing of new crops allows scientists to identify potential allergens before a food product
reaches the market.
Many genetically engineered plants are
stronger and more durable, able to resist
droughts and insecticides, and
allow farmers to produce
more plants every year.
Some scientists say that
genetically engineered
plants are the key to
staving off world
hunger. But to be
certain of no harm to
humans, the U.S. Food
and Drug Administration
requires rigorous safety
testing—sometimes
taking more than a decade—before approving
a new food crop for human consumption.
There are, however, some real concerns,
which scientists need to tackle to create better GMOs. For instance, the rise of crops
that won’t die when sprayed with herbicide,
which allows farmers to spray entire fields to
kill weeds without damaging their crops, has
contributed to the rise of herbicide-resistant
weeds.
As long as researchers continue to improve
genetic modification through research and
experiments, GMO technology will remain an
important tool in the arsenal to sustain a
growing planet.
SELECTED REFERENCES
Callis, T. Papaya: A GMO Success Story. Hawaii
Tribune Herald, June 10, 2013: http://hawaii-tribune-herald.com/sections/news/local-news/
papaya-gmo-success-story.html [accessed Feb
2017].
Kuure-Kinsey, M.; McCooey, B. The Basics of
Recombinant DNA. University of Minnesota,
Department of Biochemical Engineering, Fall
2000: https://www.rpi.edu/dept/chem-eng/
Biotech-Environ/Projects00/rdna/ rdna.html
[accessed Feb 2017].
Witkowski, J. F. et al; Ostlie, K. R., Ed. et al. Bt
Corn and European Corn Borer. University of
Minnesota, Agricultural Extension Service:
http://www.extension.umn.edu/agriculture/corn/
pest-management/bt-corn-and-european-corn-
borer/#ch4 [accessed Feb 2017].
JoAnna Wendel is a science writer who lives in
Washington, D.C. Her most recent ChemMatters
article, “Performance-Enhancing Drugs: Is Winning
Everything?” appeared in the October/November
2014 issue.
What really happens when
you eat, say, genetically modified corn is the same thing that
happens to any protein that you
digest every day. When the corn enters
your mouth, your teeth and enzymes in your
saliva start to break down the food. When
you swallow the food, it enters your stomach,
where more chemicals start to denature the
proteins—which means breaking the hydrogen bonds that give them their 3-dimensional
shape. Once the proteins are unfolded into
long spaghetti-like strands of amino acids, the
lining of the stomach releases another enzyme
called pepsin which attacks the proteins at
their peptide bonds—the bonds that hold
amino acids together.
To break apart amino acids, a chemical reaction called hydrolysis occurs. Pepsin binds to
the protein so its molecular bonds are exposed
to stomach acid and water, which results in
hydrolysis—whereby a water molecule interacts with the bond between a carbon atom and
the nitrogen that immediately follows it, also
called a peptide bond (Fig. 2), where it donates
a hydrogen atom and a hydroxyl group to
separate the protein in two.
Then, these peptide chains
travel into your small intestine, where other types
of enzymes break down
the peptide chains into
even smaller peptide
chains, as well as amino
acids, which can then be
absorbed and used by
your body.
This whole process
works the same way in food
