Burping Yeast: An Investigation of Cellular Respiration
Teacher Materials
Leaning Goals, Objectives, and Skills .................................................................2
Standards Alignments ..........................................................................................3
Laboratory Set-Up Manual ....................................................................................5
Instructor Laboratory Guide .................................................................................7
Answers to Student Questions ............................................................................8
Post-Lab Extension Activities ..............................................................................11
*Please consider adapting this lab to include some student-centered investigation.
Some suggestions, ideas, and tips can be found in a separate document called
"Student-Centered Investigation"
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Burping Yeast: An Investigation of Cellular Respiration
Learning Goals, Objectives, and Skills
Student Learning Goals:

Students will understand the basic process of cellular respiration.

Students will understand the role of enzymes in chemical reactions.

Students will understand some of the factors that can influence the rate of enzyme-controlled
reactions.
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Students will understand that starch can be used as an energy source for fermentation.

Students will understand that gluten is a type of protein.
Student Learning Objectives:

Students will articulate the function of cellular respiration and identify the reactants and products
of this reaction.
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Students will explain the role of enzymes as catalysts that lower the activation energy of
biochemical reactions.
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Students will measure the effect of temperature and other factors on cellular respiration.
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Students will determine the effect of temperature and other factors on enzyme activity.
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Students will apply their knowledge of macromolecules to help explain why bread dough rises.
Scientific Inquiry Skills:
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Students will pose questions and form hypotheses.

Students will design and conduct scientific investigations.
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Students will make measurements and record data.
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Students will use mathematical operations to analyze and interpret data.
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Students will generate tables and graphs to present their data.
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Students will use experimental data to make conclusions about the initial question and to
support or refute the stated hypothesis.
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Students will follow laboratory safety rules and regulations.
Laboratory Technical Skills:

Students will demonstrate proper use of micropipettors.
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Burping Yeast: An Investigation of Cellular Respiration
Standards Alignments
MA Science and Technology/Engineering Curriculum Framework (2006)
Biology
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1.2 Describe the basic molecular structures and primary functions of the four major categories of
organic molecules (carbohydrates, lipids, proteins, nucleic acids).

1.3 Explain the role of enzymes as catalysts that lower the activation energy of biochemical reactions.
Identify factors, such as pH and temperature that have an effect on enzymes.

2.4 Identify the reactants, products, and basic purposes of photosynthesis and cellular respiration.
Explain the interrelated nature of photosynthesis and cellular respiration in the cells of photosynthetic
organisms.

2.5 Explain the important role that ATP serves in metabolism.
Chemistry

7.2 Calculate concentration in terms of molarity. Use molarity to perform solution dilution and solution
stoichiometry.

7.5 Identify the factors that affect the rate of a chemical reaction (temperature, mixing, concentration,
particle size, surface area, catalyst).
Scientific Inquiry Skills

SIS1. Make observations, raise questions, and formulate hypotheses.

SIS2. Design and conduct scientific investigations.

SIS3. Analyze and interpret results of scientific investigations.

SIS4. Communicate and apply the results of scientific investigations.
Mathematical Skills

Construct and use tables and graphs to interpret data sets.

Perform basic statistical procedures to analyze the center and spread of data.

Measure with accuracy and precision (e.g., length, volume, mass, temperature, time)

Use common prefixes such as milli-, centi-, and kilo-.
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DRAFT REVISED MA Science and Technology/Engineering Standards (2013)
*Please note that these are DRAFT standards that have not yet been submitted for formal review or
adoption.
Biology

HS-LS1-7. Use a model to illustrate that aerobic cellular respiration is a chemical process whereby
the bonds of food molecules and oxygen molecules are broken and new bonds form resulting in new
compounds and a net transfer of energy. Contrast this process to anaerobic cellular respiration and
compare the amount of energy released in each process.
[Clarification Statement: Emphasis is on the conceptual understanding of the inputs and outputs of the process of cellular
respiration, lactic acid fermentation and alcoholic fermentation. Students should understand that molecules other than glucose
can be broken down to release energy in the form of ATP. Examples of models could include diagrams, chemical equations,
and conceptual models.]
[Assessment Boundary: Assessment should not include identification of the steps or specific processes involved in either
aerobic or anaerobic cellular respiration.]

HS-LS2-3. Construct and revise an explanation based on evidence that the processes of
photosynthesis, chemosynthesis, and aerobic and anaerobic respiration are responsible for the
cycling of matter and flow of energy through ecosystems. Explain that environmental conditions
restrict which reactions can occur.
[Clarification Statement: Examples of environmental conditions can include the availability of sunlight or oxygen.]
[Assessment Boundary: Assessment does not include the specific chemical processes of photosynthesis, chemosynthesis, of
either aerobic respiration or anaerobic respiration.]
Chemistry
 HS-PS1-5. Construct an explanation based on collision theory for why varying conditions influence
the rate of a chemical reaction or a dissolving process. Design and test ways to alter various
conditions to influence (slow down or accelerate) rates of processes (chemical reactions or
dissolving) as they occur.
[Clarification Statement: Explanations should be based on three variables in collision theory: quantity of collisions per unit time,
molecular orientation on collision, and energy input needed to induce atomic rearrangements. Conditions that affect these
three variables include temperature, pressure, concentrations of reactants, mixing, particle size, surface area, and addition of a
catalyst.]
[Assessment Boundary: Assessment is limited to simple reactions in which there are only two reactants and to specifying the
change in only one variable at a time.]
NRC Practices
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Asking questions and defining problems
Planning and carrying out investigations
Analyzing data
Mathematical and computational thinking
Constructing explanations and designing solutions
Engaging in argument from evidence
Obtaining, evaluating, and communicating information
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Burping Yeast: An Investigation of Cellular Respiration
Laboratory Set-up Manual
Note: The set-up procedure below is designed for groups of three.
Supply List:
For lab preparation:
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250-mL Erlenmeyer flask
10 g lyophilized yeast
9 g glucose
round bottom tubes (e.g., Fisher Scientific catalog # 2-565-971) or small containers like portion
cups (e.g., Fisher Scientific catalog # NC9698785)
2  5-L containers or carboys with spigots
3  8-L to 10-L water baths OR supplies such as hot plates and ice cubes to maintain three water
sources, with temperatures between 15C–50C and at least 10C apart.
For each group:
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3  600-mL beakers
3  test tubes (25 mm  200 mm) *Taller test tubes are critical because the entire transfer
pipette must be completely submerged (e.g., Fisher Scientific catalog # 14-915H)
1  test tube rack
3  1-mL graduated transfer pipettes (e.g., Fisher Scientific catalog # 50-819-427)
3  metal hex nuts (3/8” stainless steel) *Hex nuts must be large enough to slide over the
shaft of the transfer pipette, but small enough to fit into the test tube
3  2.0-mL microcentrifuge tubes
1  p1000 micropipettor and pipette tips
1  thermometer
timer
calculator
permanent marker (such as Sharpie)
tube of glucose solution
tube of yeast solution
microcentrifuge tube rack or beaker to hold 3 microcentrifuge tubes
Tips for supplies:

If you do not have an adequate number of 600-mL beakers, other appropriate containers for mini
water baths can be substituted.

Graduated 1-mL transfer pipettes can be substituted for the p1000 micropippetors and tips.

Consider providing students with reference points for the water temperatures they are using. For
example, 22C is room temperature and 37C is body temperature. Ask them why they aren’t
using boiling water or freezing water (A: the yeast cannot survive at those temperatures).
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Lab Set-Up Calendar:
2 weeks before lab:
 Check supplies and order any needed materials.
 If making any substitutions to the supply list, edit the student protocol accordingly.
1–3 days before lab:
 Prepare 50 mL of a 1M glucose solution:
1. Dissolve 9 g of glucose in 40 mL of water; bring to 50 mL final volume.
2. Aliquot 12  2.0-mL glucose solution into round bottom tubes.
3. Store glucose solution at 4C until ready to use.
1 day before lab:
 Set up student lab stations with all durable materials.
 Practice preparing and using a respirometer so demonstration will go smoothly
 Determine how you will maintain the temperatures of the three water sources and make any
necessary preparations.
Morning of lab:
 Set out 1M glucose solution aliquots (1 tube per station)
 Prepare 50 mL of a 20% yeast solution. *Must be made fresh the day of the lab*
1. Dissolve 10 g of yeast into 50 mL of water in Erlenmeyer flask. Add 5 mL of the 1M glucose
solution
2. Store yeast solution uncovered at room temperature until ready to use
 Check temperature of water sources and adjust temperatures if necessary. For the best results,
use water temperatures between 20C and 50C and choose three temperatures that each differ by
about 10C
As students start the pre-lab activity:
 “Activate” yeast solution by incubation at about 37C for ~15 minutes. This can be done by floating
an Erlenmeyer flask in a beaker of warm water.
 Aliquot 12  2.0-mL activated 20% yeast solution into round bottom tubes and distribute 1 tube per
station
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Burping Yeast: An Investigation of Cellular Respiration
Instructor Laboratory Guide
Laboratory Procedure Tips:
1. Before starting the experiment, ask students to check their materials list to make sure they have
everything.
2. Demonstrate how to set up the respirometer (inverted pipette apparatus) in the test tube so that
students have a model from which to work.
3. Students will work in groups of three; make sure each student in the group gets a chance to set
up a respirometer and beaker water bath.
4. Have the students set up all three respirometers and then the beaker water baths.
5. When loading the yeast-glucose solution into the transfer pipette bulb, Important! You must get
all of the solution down into pipette bulb. Students should completely depress the bulb and then
FLIP the pipette BEFORE they release the bulb!
6. Remind students to fill the test tubes with water from the water bath beakers and insert the test
tube into the corresponding beaker so it will be the appropriate temperature.
7. Since the heated water cools quickly, prepare water for each condition with the expectation that
by the time students set up and perform the assay the water will have cooled off. The following
represents preparation for one possible set of low-medium-high temperatures:
a. Student beaker water bath “A” (coolest temperature):
incubate water at room temperature for an experimental target temp of ~22C
b. Student beaker water bath “B” (medium temperature):
heat water to 42C for an experimental target temp of ~37C
c.
Student beaker water bath “C” (warmest temperature):
heat water to 55C for an experimental target temp of ~47C
8. Students should expect to see ~ 1 bubble/min at 22C and 5–7 bubbles/min at 37C and 47C.
Lab Data Analysis Tip:
While students are working on their lab generate a table on the board or projector to collect class data.
Record the total number of bubbles each group obtained for each experimental condition and calculate
the class average. You could also have students perform a t-test and calculate a p-value.
Total Number of Bubbles Over 10 Minutes
Group Number
Condition
1
2
3
4
5
6
7
8
9
10
Class
Average
Water Bath “A”
coolest temp.
Water Bath “B”
medium temp.
Water Bath “C”
warmest temp.
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Burping Yeast: An Investigation of Cellular Respiration
Answers to Student Questions
Protocol-Embedded:
p. 2:

carbon atoms from pyruvate join with oxygen to become CO 2.

Yeast release CO2 gas during both respiration and fermentation. The gas forms bubbles in the
dough that cause it to rise.
Figure 3: The metal nut keeps the transfer pipette immersed in the water within the test tube.
Pre-Lab:
1. Cellular respiration is the process by which living things transform the energy stored in
macromolecules (“food”) into energy that the cell(s) of the organism can use directly (ATP).
2. Glucose cannot be used by cells directly, but ATP can be.
3. Muscle cells are more likely to ferment during exercise because when the muscles are working
hard, there is likely to be an inadequate supply of available oxygen to meet the energy demands
of the cell by aerobic cellular respiration alone.
4. Enzymes lower the activation energy required for the cellular respiration reactions to take place.
5. By counting released bubbles
6. Sample answer: The higher the temperature, the more bubbles will be released.
7. Dependent: number of bubbles released; Independent: water temperature
Post-Lab and Analysis:
1. Because the bubble contain CO2 gas, which is released by the yeast when the ferment. More
bubbles indicate a more rapid rate of CO2 production, which in turn indicates a faster rate of
fermentation.
2. Sample graph and data table:
Copyright © MassBioEd 2013
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Time
Number of Bubbles/Minute
Beaker A
coolest-temperature
Beaker B
medium-temperature
Beaker C
warmest-temperature
Starting Temp: 22C
Starting Temp: 33C
Starting Temp: 45C
2
2
2
3
1
2
2
2
1
2
Minute 6
2
2
Minute 7
1
1
1
2
Minute 9
2
1
Minute 10
Total number
of bubbles
1
2
15
19
Minute 1
Minute 2
Minute 3
1
Minute 4
Minute 5
Minute 8
1
1
3
3. Sample answers based on data table:
Beaker A: 0.3 bubbles/minute
Beaker B: 1.5 bubbles/minute
Beaker C: 1.9 bubbles/minute
4. Sample graph:
5. Results indicate that the warmer the environment, the faster the rate of cellular respiration in the
yeast. Although yeast at temperatures above 47C may have a slow rate of respiration
6. Yeast cells have evolved to live at a narrow temperature range, and the enzymes in the yeast are
most efficient within this temperature range.
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7. Photosynthetic organisms are the primary source of oxygen in the atmosphere, so the first
organisms on Earth, which were not photosynthetic, most likely carried out a form of anaerobic
cellular respiration.
8. a. No, I do not think it would rise because the sugar is the “food” for the yeast. Without sugar, the
yeast cannot carry out cellular respiration to release the CO2, which in turn make the bubbles that
make the bread rise.
b. Different grains have different amounts of the gluten protein. In bread dough, strands of gluten
proteins form networks that increase the dough’s elasticity and help to trap the air bubbles.
Dough made from flour that contains lots of gluten is stretchier and can expand more than dough
made from low gluten flour.
9. The optimal temperature for both types of cells would be about 37C—body temperature. The
optimal pH of the muscle cell would be about 7.4 and for the stomach cell, much lower, about
1.5–3.5.
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Burping Yeast: An Investigation of Cellular Respiration
Post-Lab Extension Activities
Student Oral Presentation:
Students can report the findings of their student-centered investigations to the class using a PowerPoint
presentation that includes the following information:
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Experimental question—what you hope to learn from performing the experiment.
Hypothesis—a testable, proposed answer to the experimental question based on prior knowledge.
Experimental system and data collection methods—flowchart of how the experiment was
performed and how data was collected. This should NOT include a detailed summary.
Results—observations, data tables, figures, etc.
Conclusions—should the hypothesis be accepted or rejected as supported by key data.
Online resource for effective PowerPoint presentations:
http://office.microsoft.com/en-us/powerpoint-help/tips-for-creating-and-delivering-an-effectivepresentation-HA010207864.aspx
Student Lab Report:
Students can report the findings of their student-centered investigations through a written lab report. Your
school may have its own lab report format, but generally lab reports include the following information:
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Title—brief summary reflecting the factual content of the investigation.
Introduction—includes questions being answered, hypothesis and background information.
Materials—list of supplies needed to perform the lab.
Procedure—step-by-step procedure (with enough detail so someone could repeat the
experiment).
Results—observations, data tables, figures, etc. and a brief narrative summary of results.
Conclusion—explanation supported by evidence for whether the hypothesis should be accepted
or rejected.
Online resources for writing lab reports:
http://www.mhhe.com/biosci/genbio/maderinquiry/writing.html
http://www.ncsu.edu/labwrite/
Student Writing Exercise:
Ask students to read a current newspaper or journal article related to cellular respiration or the function of
enzymes and write a paragraph answering a series of prompts. For example, students could read the
online article From and function enzyme activity (http://www.northeastern.edu/news/2012/04/enzymes/)
and answer the following questions:
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What did Ondrechen and Beuning received their grant to study?
Why do they think their research could be used to replace standard industrial processes?
What is the name for the cavities that are on the surface of the protein (enzyme)?
How is their approach different from other current research approaches?
How and why have these scientists divided up the work?
What is remote amino acid activity?
Copyright © MassBioEd 2013
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Form and function in enzyme activity
April 5, 2012 by Angela Herring
Many industrial chemistry applications, such as drug or bio-fuel synthesis, require large energy inputs and
often produce toxic pollu-tants. But chemistry and chemical biology professor Mary Jo Ondrechen said
enzymes—proteins that increase the rate of chem-ical reac-tions in the body—could be used to
effectively replace standard industrial processes.
“Enzymatic reac-tions are cleaner, produce fewer byproducts and use less energy,” she explained. But
attempts to replicate natural enzymes for industrial applica-tions are limited by our incomplete knowledge
of these proteins.
Ondrechen and Penny J. Beuning, an assistant professor of chemistry and chemical biology, have
received a three-year, $565,000 grant from the National Science Foundation to develop a better
understanding of enzyme activity.
“If you want to design proteins to catalyze a particular reaction, it’s good to understand how they work,”
said Ondrechen.
Enzymes, she explained, are made up of a string of amino acids coded by the gene sequence. Each
amino acid has a different role in the protein: Some are structurally important while others are required for
the enzyme’s catalytic properties.
“There are cavities on the sur­face of a protein where a molecule can come in and sit down,” Ondrechen
said. “The enzyme does a reaction on it and the product goes away.”
The current body of research on enzyme activity mostly focuses on the amino acids in that cavity, which
come into direct contact with the reac-tive molecule. But over the years, some research has sug-gested
that amino acids far away from the active site also play a role in catalysis.
Ondrechen’s team, using a method she developed 10 years ago, will be able to predict which remote
amino acids will impact reactivity. Beuning’s team will test these predic-tions experimentally.
“My lab is really inter­ested in specificity of enzymes,” Beuning said. “We look enzymes and figure out
how they recognize their substrates.”
To do this, her team takes a protein engineering approach in which they manipulate the enzyme’s
composition and observe how it affects its function.
Beuning’s experimental data can be used to train the computational method to make even better
predictions about which amino acids are important to catalysis.
“There is a nice syn-ergy between our interests,” she said. “We can take the computational work from
Ondrechen’s lab, add the experimental work to it and then take the experimental results and say, ‘Did it
work? Are there subtleties that we’re missing?’”
By building a library of enzymes known to have remote amino acid activity, the group can even-tu-ally
begin to answer fundamental research questions in the quest to improve industrial enzymatic chemistry
techniques.
See more at: http://www.northeastern.edu/news/2012/04/enzymes/#sthash.7jcoLrPz.dpuf
Source: http://www.northeastern.edu/news/2012/04/enzymes/
Copyright © MassBioEd 2013
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Websites:
Cellular Respiration
http://www.phschool.com/science/biology_place/biocoach/cellresp/intro.html
http://concord.org/stem-resources/cellular-respiration
Enzymes
http://www.wiley.com/college/boyer/0470003790/animations/animations.htm
http://workbench.concord.org/database/browse/concept/Molecular%20Biology/425.html
Videos:
Cellular Respiration
http://www.youtube.com/watch?v=j7gPtASv0SQ
http://www.youtube.com/watch?v=Gh2P5CmCC0M
http://www.youtube.com/watch?v=0IJMRsTcwcg
Enzymes
http://www.youtube.com/watch?v=ok9esggzN18
http://science.howstuffworks.com/life/28733-assignment-discovery-enzyme-catalysts-video.htm
Games:
Cellular Respiration
http://www.quia.com/rr/216170.html
Enzymes
http://www.glencoe.com/olc_games/game_engine/content/gln_fcsce/fs_nat_06/ch19/
http://sciencereviewgames.com/srg/games/hs.php?id=83
Related Experiments:
Cellular Respiration
http://serendip.brynmawr.edu/sci_edu/waldron/pdf/IsYeastAliveProtocol.pdf
http://serendip.brynmawr.edu/sci_edu/waldron/#fermentation
http://www.redstaryeast.com/science-yeast/yeast-experiments
Enzymes
http://library.thinkquest.org/28599/experiment_how_do_enzymes_work.htm
http://www.phschool.com/science/biology_place/labbench/lab2/intro.html
http://www.ableweb.org/volumes/vol-6/10-miller.pdf
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Practice MCAS Open Response Question:
The following open-response question from the spring 2013 Biology MCAS test probes student
understanding of the effects of temperature on enzyme activity.
Sample student responses can be found at:
http://www.doe.mass.edu/mcas/search/answer.aspx?questionid=29504
• BE SURE TO ANSWER AND LABEL ALL PARTS OF THE QUESTION.
• Show all your work (diagrams, tables, or computations) in your Student Answer Booklet.
• If you do the work in your head, explain in writing how you did the work.
Catalase is an enzyme that protects cells from damage by helping convert the toxin hydrogen peroxide (H2O2)
into water (HO2) and oxygen (O2). A student is investigating how different pH values and different
temperatures affect catalase activity. The table below shows the student’s data.
Catalase Experiment Data
Test Tube
Amount of
Catalase
(drops)
Amount of
Hydrogen
Peroxide
(mL)
pH of
Solution
Temperature
of Solution
(°C)
Relative Rate of
Reaction
1
10
3
1
5
no reaction
2
10
3
1
30
no reaction
3
10
3
1
60
no reaction
4
10
3
3
5
very slow reaction
5
10
3
3
30
slow reaction
6
10
3
3
60
no reaction
7
10
3
7
5
slow reaction
8
10
3
7
30
rapid reaction
9
10
3
7
60
no reaction
a. Identify the test tube that most likely has physical conditions similar to the conditions in human cells.
Explain your answer.
b. Describe how catalase activity changes as pH decreases. Use data from the table to support your answer.
c. Describe how catalase activity changes as temperature increases. Use data from the table to support your
answer.
d. Explain why temperature affects catalase activity in the way you described in part C.
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Practice AP Exam Questions:
The following multiple-choice questions were pulled from the fall 2012 AP Biology Course and Exam
Description booklet.
An experiment to measure the rate of respiration in crickets and mice at 10°C and 25°C was performed using
a respirometer, an apparatus that measures changes in gas volume. Respiration was measured in mL of O 2
consumed per tam of organisms over several five—minute trials, and the following data were obtained.
Organism
Temperature (°C)
Average respiration
(mL O2/g/min)
Mouse
10
0.0518
Mouse
25
0.0321
Cricket
10
0.0013
Cricket
25
00038
According to the data, the mice at 10°C demonstrated greater oxygen consumption per gram of tissue than
did the mice at 25°C. This is most likely explained by which of the following statements?
(A) The mice at 10°C had a higher rate of ATP production than the mice at 25°C.
(B) The mice at 10°C had a lower metabolic rate than the mice at 25°C.
(C) The mice at 25°C weighed less than the mice at 10°C.
(D) The mice at 25°C were more active than the mice at 10°C.
Experimental evidence shows that the process of glycolysis is present and virtually identical in organisms
from all three domains, Archaea, Bacteria, and Eukarya. Which of the following hypotheses could be best
supported by this evidence?
(A) All organisms carry out glycolysis in mitochondria.
(B) Glycolysis is a universal energy-releasing process and therefore suggests a common ancestor for all
forms of life.
(C) Across the three domains, all organisms depend solely on the process of anaerobic respiration for
ATP production.
(D) The presence of glycolysis as an energy-releasing process in all organisms suggests that convergent
evolution occurred.
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