Photosynthesis and Artificial Photosynthesis:
Learning Biology Through Its Engineering Application
Yu d a An r i a n y
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Pr in c e Ge o r g e ’s C o mmu n ity C o lle g e
A FA C C T C o n f e r e nc e 2 0 1 4
Pr in c e G e o r g e ’s C o m m u n i ty C o l l e g e , L a r g o , M D
Po s te r Se s s i o n ( Se s s i o ns 2 C An d 6 C )
J a n u ary 9 An d 1 0 , 2 0 1 4
RET in Engineering
NSF Grant No: 1009823
Directorate for Engineering
What is photosynthesis? Although many students can correctly
answer that it is a process in which light energy is converted into
food, few would be able to describe the process of energy conversion
What happens if the students are told that the same molecular
process of natural photosynthesis is used in artificial photosynthesis
to capture solar energy in a solar cell? (1) In my BIO1140 class, the
answers are excitement and engagement.
The topic of artificial photosynthesis is one that I used to engage
students in learning photosynthesis at the molecular level. By
introducing students to the applications of biology in another
fields, students were able to see the extent of the importance of
the concept they learn. Since solar cell is a subject that students
can relate to, students were more motivated to learn the
concept much more deeply.
This curriculum element was developed as part of my
participation in the Research Experience for Teachers (RET)
program in which my summer research in Dr. Sheryl Ehrman’s
laboratory in the Department of Chemical and Biochemical
Engineering at the University of Maryland was implemented in
Principles of Biology: Cellular and Molecular Biology (BIO1140)
course at Prince George’s Community College.
Photosynthesis vs. Artificial Photosynthesis
Both photosynthesis and artificial photosynthesis use light energy to
split water molecule.
In natural photosynthesis, the light energy is captured by the
chlorophyll in the reaction centers in the two photosystems that
work together. The energy is used to excite electrons originated from
water molecules, releasing hydrogen ions and oxygen (see Figure 1).
The electrons then travel through a series of proteins which
eventually result in the generation of ATP and NADPH energy that is
used to form chemical bonds during conversion of CO2 to glucose.
This process is highly efficient: almost 100% of light energy that hits
the reaction center is used to excite electrons.
The photovoltaic system in solar cells also captures light energy by a semi
conductor such as silicon to excite electrons, which then travels and produce
energy in a form of current. Artificial photosynthesis is employed in Photo
Electrochemical Cells (PEC), where instead of forming chemical bonds or
producing currents, the light energy that has been harnessed is used to split
water molecules to produce H2 and O2 (see Figure 1) in solar cells that are so
called artificial leaf (2). Hydrogen fuel can be stored and used as an alternative
source of energy in place of fossil fuels. The engineering aspect of artificial
photosynthesis is still the subject of current research, due to its low efficiency
and/or the high cost.
In this project, students had an opportunity to learn both photosynthesis and
artificial synthesis through a case study, and to have a hands-on experience to
build a mini solar cell called DSSC that uses organic dye and nanocrystalline
titanium dioxide. This solar cell is inexpensive, although the efficiency is very
Figure 1. Conversion of Light Energy in a Leaf
(A) and in a Solar Cell (B)(4, 5)
To engage students in learning the concept of energy conversion
in photosynthesis and its application in artificial photosynthesis
To promote critical thinking in comparing and contrasting
photosynthesis and artificial photosynthesis
Essential Questions (3)
How does photosynthesis take place with only two simple
How does the chlorophyll pigment convert sunlight energy to
How is the photosynthesis reactions used as a basis for
constructing hydrogen solar cell?
The Understanding Process
• A Case Study introduces the concept of
photosynthesis in simple terms
• Self study, group and class discussion on natural
photosynthesis process reinforces understanding of
Case I concept
• Building a DSSC solar cell introduces application of
• Literature research on models of hydrogen solar
cells (PEC), class presentation on photosynthesis and
artificial photosynthesis promotes exploration and
Case II critical thinking
• Understanding of the concept of photosynthesis and
Students in BIO 1140 built the Dye-sensitized Solar Cell (DSSC) and
presented their research on PEC designs as part of the project in learning
photosynthesis. The solar cell is pictured in the center.
The Most Important Concepts Learned
Significant role of a water molecule on photosynthesis/artificial photosynthesis
Process of making solar energy into another ATP (photosynthesis) and H2+O2
Other ways to create energy, that unlike fossil fuels won’t negatively affect
earth; lots of substances that can do job of chlorophyll
Importance and need of artificial photosynthesis
Energy transfers between photosystems I & II
Evaluation: Students’ Comments
“Learn how scientists and engineers work together”
“Photosynthesis is not just for plants, but can be used to generate
“In depth knowledge of a very thorough topic (fossil fuels, global issue)
that cannot be forgotten”
“Being able to compare it to something else meant fully understanding
“Requiring to explain material to the class motivated me to learn
“Helpful, but too much work on top of other things”
“Conducting research [on PEC] was challenging because of unfamiliar
“Working in groups was difficult because impossible to get together”
and Lessons Learned
Developing and integrating curriculum element:
Writing a case study was challenging
Integration was overwhelming because lab and presentation were
added to a preexisting lab and lecture
Presenting the curriculum element:
Gratifying to see students’ engagement in learning using methods
different from traditional lecture
Evaluating curriculum element:
Manual analysis of survey was challenging
The interdisciplinary method to teach photosynthesis has promoted students’
engagement in learning basic Biology, as shown in the survey results. Students
enjoyed learning through untraditional means and got memorable lessons.
This may stem from the close relevance of the application of the
photosynthesis to students’ real lives. Students were more willing to delve
deeper into the concept knowing the value of what they learn. The use of a
case study, which is inquiry based, a hands-on activity, and the availability of
resources also had facilitated the learning.
In the future, I plan to gauge students’ understanding by comparing exam
grades from a class that does and does not use the project.
Finally, I believe that this approach of combining two different fields of study
can also be applied in other disciplines as long as it is highly relevant to
student’s life and that the relationship between the two fields is clearly
Other, possible interdisciplinary applications
Political Science and Journalism
Math and Finance
Steroid Abuse (Chemistry and Health)
Neurogenerative Disease- (Chemistry and Biology)
Drug Addition (Chemistry and Sociology)
This project was completed during participation in the RET program in the
laboratory of Prof. Sheryl Ehrman in the Department of Chemical and Biomolecular
Engineering at the University of Maryland. Many thanks to Dr. Ehrman and Dr. ChiaYing Chiang for their assistance in learning about PEC. Thanks to Dr. Ehrman, Dr.
Isabel Lloyd, and Dr. Leigh Abts for their help in developing the curriculum element.
The curriculum implementation was also supported by the RET program.
Gust, Devens. 1996. Why Study Photosynthesis?
Regalado, Antonio. 2010. Reinventing the Leaf. Scientific American 303, 86 – 89.
Wiggins, Grant and Jay McTighe (2006). Understanding by Design. Pearson: Merrill Prentice
Yarris, Lynn. Tapping into Solar Energy Riches: Berkeley Lab’s Helios Project and the Solar
Energy Research Center. Lawrence Berkeley National Laboratory.
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