General Instructions for Coding DQC Responses
Responses to DQC questions can be grouped into three general categories; Informal, Mixed or
Scientific. These three categories encompass a wide range of reasoning abilities, but all three categories
are common among college students. The table below describes the general types of responses that
would be associated with each level of reasoning. In addition, the levels of reasoning are assigned a
numerical value for coding purposes. Codes 2-4 are used for responses that attempt to answer the
question, while codes 1a-1e are reserved for missing responses or those that provide no information
about student reasoning.
Code
4
3
2
1a
1b
1c
1d
1e
Level
Scale
Successful use of
other scales to
explain macroscopic
phenomena
Processes described
in terms appropriate
for that scale
Partially successful
attempts to connect
scales, but with some
inappropriate use of
macroscopic ideas at
other scales
Matter
Reactants and products described
as chemical substances
Accounts of processes describe
Principled
transformation of reactants into
reasoning
products in ways that conserve
atoms at the atomic-molecular
scale and mass at larger scales.
Less than completely successful
attempts to conserve matter.
Reactants and products described
as material kinds, but atoms not
Mixed
traced through chemical processes
reasoning
and matter-energy
transformations may be used as a
“fudge factor.)
No attempt to make
Material inputs or needs and
connections across
products or results are mentioned,
scales for questions
but not in ways that clearly
posed at
distinguish matter, energy, and
macroscopic scale
conditions.
Informal
Inappropriate use of
No indication that the student is
reasoning
macroscopic scale
reasoning about transformation of
ideas at other scales
matter: no account of how
material inputs are transformed
into results.
Missing data (e.g. responses or codes lost after exam was taken and coded)
Student did not reach question
Student skipped question
I don’t know or equivalent
Nonsense answer that is not responsive to question
Energy
Forms of energy are clearly
identified and distinguished
from forms of matter.
Energy transformation
described in ways consistent
with energy conservation.
Energy is recognized as a
distinct entity, but sometimes
in ways that do not clearly
distinguish energy from matter
(e.g., glucose, ATP) and/or
conditions (e.g., temperature).
Accounts fail to conserve
energy.
“Energy” used in an informal
sense as something that makes
events happen.
No clear distinction between
energy sources and other
needs or inputs.
These general ideas for coding above are applied to each individual question below to provide specific
details for how to code each question. Still, you will find that the specific coding rubric for each
question does not list every possible answer that you might see. In these cases, refer back to the general
rubric above, and try to be as objective as possible. You will undoubtedly find responses that don’t quite
fit a specific category, but seem to be in between. For these scenarios, we suggest that you assign a 2.5
or 3.5 code to the student.
Digestion/Biosynthesis Diagnostic Question Clusters– ANSWER KEY
The transfer of matter and energy within and between organisms is a complex process that is better understood by
identifying and tracing specific matter and energy entities. Digestion and Biosynthesis are two important topics in
Biology courses and have implications for organisms and ecosystems. Yet, many of the details are occurring at
the cellular level. Two parallel DQCs covering the topics of Digestion and Biosynthesis (BA & BB) are designed
to help decipher student reasoning about these topics, particularly related to their understanding of matter and
energy through these important processes.
Organization of questions in Digestion/Biosynthesis DQCs.
Biosynthesis Form A (BA)
2 Matter Items
COYOTE (1)
GIRLGROW (4)
Biosynthesis Form B (BB)
2 Matter Items
APPLEDIG (2)
COYOTE (3)
2 Energy Items
GRAPGLUC (3)
PEOPENER (2)
2 Energy Items
ENERGAIN (1)
PEOPENER (4)
1 Large Scale Cross Process Item
BIOFUEL (6)
1 Large Scale Cross Process Item
KLGSEASON (5)
1 Small Scale Cross Process Item
CARBPATHS (5)
1 Small Scale Cross Process Item
EATBREATHE (6)
Diagnostic Question Cluster Form BB– ANSWER KEY
ENERGAIN
1. Of the energy gained by plants, about what percent is transferred to herbivores like rabbits?
a. 90-100%
b. 60-70%
c. 30-40%
d. 10-20%
If you chose B, C or D, where does the energy go that does not get transferred between the plant and rabbit?
Correct, Scientific Answer: The energy that is not transferred is lost as chemical bond energy in the feces of the rabbit, or is
lost as heat during the process of cellular respiration.
Processes = Digestion/Biosynthesis, Respiration, Principles = Energy, Scale, Scale = Ecosystem -> Atomic/Molecular
Purpose of Question: This question explores whether students can trace energy through a food chain. Students who choose
answers A or B do not understand the principles associated with the transfer of energy between organisms. More commonly,
students do not know where the energy goes that is lost, commonly citing that it is “used up” or “gone.”
Coding Rubric
Code
Example Student Responses
4 - Scientific
-D: it’s given off as heat, waste, and probably
something else that I can’t remember
3 - Mixed
- C, The energy that is not transferred to the
rabbit is lost by the rabbits digestion of the plant
and may be released as heat energy from the
rabbit
- C, It stays with the plant if it is not fully eaten
or it is in the ground
-B, not all of it can be digested and absorbed by
the rabbit
2 - Informal
-D, used in plant process or wasted because
energy transfer is not efficient, i.e. plants used
more energy to make glucose than they get from
it
- D, it is lost
Description
- Student chooses D and correctly traces energy when
it is decoupled from matter during the process of
oxidation. Students may say that some energy is
released as heat or released to the atmosphere.
- Student chooses the incorrect %, but in their
explanation, they still correctly trace energy when it is
decoupled from matter during the process of
oxidation. Students may say that some energy is
released as heat or released to the atmosphere.
Students are having trouble with the magnitude, but
not the concept.
-Student chooses "D" and provides no explanation.
-Student chooses any %, but does not correctly trace
energy when it is decoupled from matter during
oxidation. They may say that energy goes somewhere
(e.g. feces, stays in the plant, is in the rabbits body),
but DO NOT include energy emitted as heat during
oxidation. However, they DO NOT use phrases like
“used up” or “goes away” nor do they give an
indication that they think energy can disappear.
- Student chooses C and provides no explanation.
- Student chooses any %, but does not correctly trace
energy. The student cites that the energy is used to
power other processes like photosynthesis or
transformation, but they do not say where the energy
went (i.e. name a location).
- Student chooses A or B and provides no explanation,
APPLEDIGA
2a. An apple is eaten by a boy and digested in his body. What happens to the apple when it is digested?
Correct, Scientific Answer: The apple first enters the boy’s digestive system (stomach, intestines) where enzymes
and bacteria break down complex molecules in the apple into smaller molecules that diffuse or are transported
into the bloodstream. These smaller molecules are moved throughout the body through the bloodstream where
they are used primarily for synthesis of biomolecules or cellular respiration. Some of the apple remains in the
digestive system and leaves as feces. During cellular respiration, chemical potential energy stored within the
molecules is transferred to other molecules like ATP.
Processes = Digestion/Biosynthesis, Principles = Matter, Energy, Scale, Scale = Organismal ->
Atomic/Molecular
Purpose of Question: This question involves all three principles of interest; matter, energy and scale. Often,
digestion and biosynthesis are “black boxes” in the minds of students. This open ended question provides an
opportunity for students to write detailed responses that account for mechanisms of matter and energy
transformation.
Coding Rubric
Code
Example Student Responses
- The apple first enters the boys digestive
system (stomach, intestines) where enzymes
and bacteria break down complex molecules
in the apple into smaller molecules that
diffuse into the bloodstream. These smaller
molecules are moved throughout the body
through the bloodstream where they are
used primarily for synthesis of biomolecules
or cellular respiration. Some of the apple
remains in the digestive system and leaves as
feces. During cellular respiration, chemical
potential energy stored within the molecules
is transferred to other molecules like ATP.
Description
-Student describes the apple being digested into
simpler molecules. The molecules move
throughout the body and are utilized in
biosynthesis and or cellular respiration.
3 - Mixed
-The apple is converted to glucose and used
as energy by the body.
- It gets broke down and released as Co2
and H2O
-Student describes specific molecules and/or
pathways the molecules take during / after
digestion, but explanation is incomplete or
incorrect.
2 - Informal
- It gets broken down and absorbed by the
body
It is broken down and the boy gets energy
from it.
-The apple is broken down and excreted out
of the body
-Student makes no reference to specific
molecules after the molecule is digested, or
pathways these molecules take during and
following digestion. Often times, students explain
the apple is “broken down” and “absorbed” or
“excreted” from the body, and sometimes the boy
gets “energy” from it.
4 - Scientific
APPLEDIGB
b. Do you think the apple the boy ate can help parts of his body (like his fingers) to grow?
Please circle one: YES
NO
If you answered YES, please explain how an apple that goes to the boy’s stomach can help his fingers to grow. If
you answered NO, please explain how the boy’s body makes his fingers grow.
Correct, Scientific Answer: The complex molecules of the apple are broken down to simpler molecules that can
diffuse into the bloodstream. These simple molecules are transported by the blood stream to parts of his body
(fingers) where cellular scale processes are involved in synthesizing simple molecules into larger biomolecules,
such as the tissues making up the finger.
Processes = Digestion/Biosynthesis, Principles = Matter, Scale, Scale = Organismal -> Atomic/Molecular
Purpose of Question: This part of the question explicitly focuses on how the food we eat can be incorporated
into body tissues, which is a subset of part A of the question. Students need to trace the matter within the apple
through the digestion and biosynthesis processes, and do this at sub organismal scales, while the question is posed
at the organismal scale.
Coding Rubric
Code
Example Student Responses
4 - Scientific
-Yes: The apple is digested in the boy’s stomach
and intestines. The complex molecules of the
apple are broken down to simpler molecules that
can diffuse into the bloodstream. These simple
molecules are transported by the blood stream to
parts of his body (fingers) where cellular scale
processes are involved in synthesizing simple
molecules into larger biomolecules, such as the
tissues making up the finger.
3 - Mixed
-Yes: Because the nutritions inside the apple will
be transported to our entire body through blood
vessels.
- Yes: Glycolysis happens and then the citrus
acid cycle creating energy and other beneficial
substances for the body.
2 - Informal
- No: The boy’s body uses chemicals and
nutrients synthesized in the body to grow.
-No: By eating things with calcium, by drinking
milk to grow his bones. That will make his fingers
grow.
-Yes: The energy from the apple is transferred
through the boys body which works with the body
to make it grow.
Description
-Student chooses Yes and provides an account that
includes accurate atomic/molecular descriptions of the
apples molecules moving through the blood stream
and being incorporated into biomolecules through
biosynthesis.
-Student chooses Yes but provides a non-descriptive
account of how this process could happen. For
example, a student might include ideas about
biosynthesis, but not transfer through the blood
stream, or vice versa.
-Student chooses Yes, but describes that the apple is in
some way converted into energy.
-Student chooses No
-Student chooses Yes and provides an explanation that
lacks mechanisms and lists the apple and it’s
components as enablers for growth.
COYOTE
3. Coyotes are primarily carnivores. Their bodies include many substances, including proteins in all their cells. What percent
of the carbon atoms in a coyote’s body were once in the following substances and locations? Fill in the blanks with the
appropriate percentages; you may use 0% in your response if you feel it is appropriate. The percentages will add up to more
than 100% if you think that the same carbon atoms could have gone through two or more of these places on their way to the
coyote.
100 % from CO2 that was used by plants for photosynthesis
100 % from animals that the coyote ate
0 % from CO2 that the coyotes inhaled
0 % from O2 that the coyotes inhaled
0 % from water that the coyotes drank (not including substances in the water)
0 % from soil nutrients that plants absorbed while growing
Please explain your answer.
Correct, Scientific Answer: Coyotes are carnivores, which means they obtain carbon atoms from other animals which are
their prey. The carbon atoms in the prey are digested, transported through the blood stream of the coyote and incorporated
into tissues. All of the carbon atoms in the prey of the coyote were once carbon dioxide in the atmosphere that was utilized by
plants for photosynthesis. Animals in lower trophic levels ate the plants, and the animals were consumed by the coyote.
Coyotes do not obtain biomass by breathing CO2. Oxygen gas is a reactant in cellular respiration, but the oxygen atoms
leave the body in water and carbon dioxide molecules and are not incorporated into the coyote’s body. Water and soil
nutrients do not contain carbon, thus the final two answers should be 0%.
Processes = Digestion/Biosynthesis, Respiration, Principles = Matter, Scale, Scale = Organismal -> Atomic/Molecular
Purpose of Question: This question assesses whether students can account for the source of the matter in a secondary
consumer’s body. The question requires that students understand that carnivores do not eat plants, that they get
the majority of their mass from eating other animals, that they do not assimilate inhaled CO2, and that coyotes
intake oxygen and water, but that these molecules do not contain carbon atoms. Exception: there may be a small
amount of carbon contained in the water they drink.
Coding Rubric
Code
Example Student Responses
4 - Scientific
-90,90,0,5,5,0
3 - Mixed
2 - Informal
-70,40,30,20,10,20
-60,20,0,0,10,10: I believe the majority of the
CO2 from the coyote’s body was stored in the
plants, and some Co2 is from the animals the
coyote ate, who ate the plants.
-5, 25, 50,50, 75,10: Coyotes along with all other
animals need a lot of water and is one of the most
important nutrients. The oxygen needed is also
very important and the Co2 exhaled will split the
amount of O2 the coyote takes in.
Description
Student writes greater than or equal to 75% for both of
the first two spaces (A. CO2 used by plants and B.
animals that the coyote ate) and writes less than 10%
for the other four spaces.
Answers for the first two spaces sum to greater than
60%, but remaining criteria from Code 3 description
are not met.
Answers for the first two spaces sum to less than 60%
PEOPENER
4. People need energy to live and grow. Which of the following is/are energy source(s) for people? Circle Yes or No for each
of the following and explain your answers.
a. Water
YES
NO
b. Food
YES
NO
c. Nutrients
YES
NO
d. Exercise
YES
NO
e. Sunlight
YES
NO
f. Carbon Dioxide
YES
NO
g. Oxygen
YES
NO
Explain your reasoning in distinguishing between the “yes” and “no” answers. Specifically, what do the energy sources have
in common that makes them different from the non-energy sources?
Correct, Scientific Answer: Humans obtain energy in the form of chemical bond energy in the food that they eat. Several
other molecules above (water& nutrients) are all incorporated into the body, but are not utilized as energy sources; their
bonds contain very little chemical potential energy and processes within the human body do not utilize these molecules
during energy transfer. Oxygen is important in releasing potential energy through the electron transport chain, but is not
itself the energy source. Carbon dioxide is in the air we breathe, but is not incorporated into any bodily functions. Exercise
does not provide energy for people, but actually facilitates the loss of energy as heat because of increased cellular
respiration that is occurring. Sunlight is the primary energy source for plants, but not for humans (exception: sunlight has a
minor role in providing energy for synthesis of important vitamins within humans).
Processes = Digestion/Biosynthesis, Principles = Energy, Scale, Scale = Organismal -> Atomic/Molecular
Purpose of Question: A student that is accurately tracing energy understands that energy is stored as chemical bond energy
(i.e.- CPE) within carbon rich molecules. Students need to realize this to answer the question at a high level. The important
part of the response is that the energy is in the form of chemical bond energy.
Coding Rubric
Code
Example Student Responses
4 - Scientific
-No,Yes,No,No,No,No,No
3 - Mixed
2 - Informal
-No,Yes,Yes,No,No,No,No: Food, because that is
how we start the process of cellular respiration
acquiring energy as ATP for our cells to carry
out work. We get nutrients from food to carry out
the same process.
-Yes,Yes,Yes,No,No,No,Yes: Exercise uses
energy, people don’t do photosynthesis, again
carbon dioxide isn’t useful for cellular
respiration.
-Yes,Yes,Yes,Yes,Yes,Yes,Yes: Something needs to
work our body
-Yes,No,Yes,Yes,No,No
-Yes,Yes,Yes,Yes,No,No,Yes: Water, food,
nutrients and oxygen are all things our body
needs to survive. Exersice in the long run can
provide you with more energy.
Description
-Student chooses Yes for food and No for all other
responses, and provides no explanation or an
explanation consistent with food providing energy in
the form of chemical bond energy.
-Student chooses Yes for food and No for all other
responses, but explains that food is converted to
energy (Incorrect matter to energy conversion)
-Student chooses Yes for food and Yes for at least one
other response, but not all responses.
-Student chooses Yes for every response
-Student chooses No for “Food”
-Student explains that people create their own energy
KLGSEASONA
5. The graph given to the right shows changes in the
concentration of carbon dioxide in the atmosphere
over a 47-year span at Mauna Loa observatory at
Hawaii, and the annual variation of this concentration.
a. Why do you think this graph shows atmospheric
carbon dioxide levels decreasing in the summer and
fall every year and increasing in the winter and spring?
Correct, Scientific Answer: The graph shows these intra-
annual oscillations because of the balance between
photosynthesis and respiration by organisms on Earth.
During the summer in the Northern Hemisphere, plants are growing, photosynthesizing, and taking carbon
dioxide out of the atmosphere. In the winter, plants are not growing, and photosynthesize, but plants, animals,
microbes and other organisms are still respiring, thus releasing carbon dioxide to the atmosphere.
Processes = Photosynthesis, Digestion/Biosynthesis, Respiration, Principles = Matter, Scale, Scale = Ecosystem
-> Atomic/Molecular
Purpose of Question: Here, we’re asking students to make a connection between the cellular processes of
photosynthesis and respiration to a large scale phenomenon: atmospheric composition. Students struggle to
provide responses that aren’t centered on human dimensions, but instead incorporate the differences between
photosynthesis and respiration at different times of the year. Many answers focus on the amount of fossil fuel use
for driving and/or heating homes. Although this is driving the upward trend overall, it reveals that the students
aren’t reasoning about carbon transformations across “natural” and anthropogenic processes similarly.
Coding Rubric
Code
4 - Scientific
3 - Mixed
2 - Informal
Example Student Responses
-There is less plant activity in the winter and
spring, allowing less CO2 to be taken up,
and vice versa.
- Plants die in the winter, therefore there is a
buildup of CO2.
- In Hawaii, the sun is closer in the winter
and spring and plants thrive and produce
CO2.
-It’s really hot there in the summer so the
plants stomas close creating less CO2.
- We use more energy in the winter because
it is getting colder. Spring is still cold and
we are using more energy to heat our homes
and it gets converted into CO2.
Description
-Students make a connection between graph
oscillations and biological processes with clear
mechanisms (photosynthesis fixing CO2 or
respiration releasing CO2)
-Students make a connection between graph
oscillations and plant growth, but the
mechanisms aren’t clear.
-Students make no accurate connections
between biological processes and graph
oscillations.
KLGSEASONB
b. Why do you think this graph shows atmospheric carbon dioxide levels increasing from 1960 to 2000?
Correct, Scientific Answer: Human activities such as the combustion of fossil fuels and land use change (e.g.
decomposition of organic materials and less photosynthesis) have resulted in large amounts of carbon dioxide
released to the atmosphere via oxidation of organic carbon containing molecules. These activities continue year
after year, causing the increase in atmospheric carbon dioxide levels over time.
Processes = Photosynthesis, Respiration, Combustion, Principles = Matter, Scale, Scale = Ecosystem ->
Atomic/Molecular
Purpose of Question: This question asks students to identify the source of carbon dioxide that is driving a
continual increase in the atmospheric concentration, which comes back to balancing sources and sinks for carbon
dioxide, and how humans have manipulated these processes. Many students acknowledge the excess carbon
dioxide being emitted from human activities. Still, some attribute the sharp rise to volcanic activity or natural
cycles.
Coding Rubric
Code
4 - Scientific
3 - Mixed
2 - Informal
Example Student Responses
- CO2 levels increase from 1960-2000
because of the increased usage of fossil
fuels.
-Human made pollutants from cars,
factories, etc. weaken the atmosphere and
trap more CO2
-More cars are polluting the air and the
plants can’t keep up.
- More people are contributing to the CO2
levels. Also cars and other machines have
become more available.
-More plants, trees, awareness
-Global warming
Description
-Students make connection between rising CO2
levels and human activities responsible for
excess CO2 production, identifying the specific
processes that produce CO2 (combustion/usage
of fossil fuels, possibly land use changes)
-Students make connection between human
activities and rising CO2 levels, either
accurately identifying sources without
specifying processes or accurately identifying
processes while suggesting that something other
than CO2 is a key product.
-Students make no accurate connection between
rising CO2 levels and human activities
contributing to the rising levels.
EATBREATHE
6. Humans must eat and breathe in order to live and grow. Are eating and breathing related to each other? (Circle
one) YES
NO
If you circled “Yes” explain how eating and breathing are related. If you circled “No” then explain why they are
not related. Give as many details as you can.
Correct, Scientific Answer: Eating and breathing independently provide molecules necessary for the process of
cellular respiration in the body. The food we eat is digested into simple carbon containing molecules, including
glucose, which is a reactant in the cellular respiration process. Breathing provides oxygen gas, which is also a
reactant in cellular respiration. Both molecules move through the bloodstream to cells where respiration takes
place. Carbon dioxide and water are products of cellular respiration, both of which are exhaled during breathing.
Processes = Digestion/Biosynthesis, Respiration, Principles = Matter, Scale, Scale = Organismal ->
Atomic/Molecular
Purpose of Question: Model based answers to this question require connecting the common carbon and oxygen
atoms in both processes, and understanding that these atoms move between gaseous and solid molecules. Most
students will probably answer “yes,” but most of those students will describe the process of eating providing
“energy” or “fuel” for the other processes going on within the body, leaving the details of how it happens as a
“black box.” They may also talk about breathing as essential to provide oxygen for the body.
Coding Rubric
Code
4 - Scientific
Example Student Responses
-Yes: Cellular respiration requires both O2
from breathing and the sugars from eating
food. Without one of these, cellular
respiration would not occur and a human
would not live.
3 - Mixed
-Yes: The body breaks down the foods we eat
and then gives off CO2
2 - Informal
-No: One must eat for nutrients and one
must breathe for oxygen. They can happen
without the other but eating coincidentally
occurs when breathing occurs. Oxygen is
needed every second though.
- Yes: Eating provides the body fuel to carry
out essential activities.
Description
-Student chooses Yes and provides a clear
explanation of how molecules and atoms in food
are involved in the same cellular processes as the
gases coming in and leaving the body. Note that
students must make a connection between
organismal, cellular and atomic molecular scales.
-Student chooses Yes but provides a vague
explanation connecting the two processes, often
just listing the components of each process
separately without a connection.
-Student chooses No
-Student chooses Yes and provides an
explanation that does not trace matter, but instead
mentions enablers in food and air that allow the
body to function, such as “fuel” or “energy.”