Biology/Chemistry Interface: Teachable Unit
Teachable Tidbit:
Energy Transformations in Plants
(Photosynthesis and Respiration)
Alexie McNerthney, Annie Crater
(Portland Community College)
Benjamin Simon, Lalita Calabria,
Lauren Troyer, Richard Weiss
(The Evergreen State College)
Biology/Chemistry Interface: Teachable Unit
Learning Goals Learning Outcomes
Understand the
processes of
energy
transformation in
plants
Compare and contrast
photosynthesis and
respiration
Understand the
scientific process
Formulate hypotheses
and interpret results
Understand the role
of plants in the
global carbon cycle
Explain how changes in
plant biomass affect
carbon flow
Summative
Assessment
Formative
Assessment
Interpret a graph
comparing [CO2] in
plants treated with
herbicides targeting
metabolic
processes.
Students
develop a
hypothesis
from
observations of
herbicide
effects on plant
growth.
Diagram the carbon
cycle
Work in groups
to predict
effects of global
plant biomass
(or atmospheric
CO2)
Context
• Topics explored previously in this
Introductory Biology or Plant Biology class
– Structure and function of chloroplasts and
mitochondria
– Role of chemiosmosis
– Potential and chemical energy conversions
– Reactants and products for photosynthesis
– Reactants and products for respiration
Learning Outcomes
• Compare and contrast photosynthesis and
respiration
– Which processes are common to both plants and animals
– Which processes are unique to each
• Practice using the scientific method to:
– Form a hypothesis
– Interpret data
(Discuss with small groups)
Scenario: You are a farmer trying to eliminate an
invasive plant on your farm but you don’t want to kill
the beneficial pollinating insects like bees and moths.
You tested two chemicals for effectiveness.
Product 1 killed the plants, but also killed insects.
Product 2 killed only the plants.
Generate hypotheses to explain these observations.
Be prepared to share your reasoning behind your
hypotheses. (5 minutes)
(Formative Assessment)
You apply the different herbicides to germinating
seeds. Product 1 targets which metabolic process
that is not targeted by product 2?
Product 1
Control
A. chemiosmosis
B. photosynthesis
C. respiration
D. regeneration of Rubisco
E. ATP production
Product 2
(Formative Assessment)
You apply the different herbicides to germinating
seeds. Product 1 targets which metabolic process
that is not targeted by product 2?
Product 1
Control
A. chemiosmosis
B. photosynthesis
C. respiration
D. regeneration of Rubisco
E. ATP production
Product 2
Why is the answer “C”
and not “A” or “E”?
…A and E both occur in
mitochondria also.
(Summative Assessment)
Note: could be a
free answer or
sequential t/f
question
Leaf CO2 Concentration (ppm)
• Your neighborhood wants to use a product to control dandelions
at the park without harming the animals. Experimental data on
the two products are shown below. CO2 concentration in leaves
was measured after different treatments (red arrow). When
interpreting the graph below recall that atmospheric CO2
concentration is about 390 ppm. Which product would you want
to use?
400
395
390
Product X
Product Y
control
385
380
375
Time (minutes)
Alternate Scenario
You are a restoration ecologist at a local prairie. You
are trying to eliminate an invasive grass that is
outcompeting native grasses. In the trials you tested
two herbicides for effectiveness. Herbicide 1 killed
the grass, but also killed an endangered butterfly.
Herbicide 2 killed only the grass.
Generate hypotheses to explain these observations.
Be prepared to share your reasoning behind your
hypotheses. (5 minutes)