photosynthesis and cellular respiration

Investigate Photosynthesis and Cellular Respiration
with Algae Beads
Bio-Rad Biotechnology Explorer

Biotechnology Explorer™ | explorer.bio-rad.com2
Curriculum and Training Specialists
Leigh Brown
leigh_brown@bio-rad.com
Sherri Andrews, Ph.D.
sherri_andrews@bio-rad.com
Damon Tighe
damon_tighe@bio-rad.com
Tamica Stubbs
tamica_stubbs@bio-rad.com

Bio-Rad Resources
@BioRadEducation
Biotechnology: A Lab Skills
Course
Pinterest.com/teachbiology
@BioRadEducation
bit.ly/b-rdropbox
bit.ly/algaebeads

Today you get think like a student…
Photosynthesis & Cellular
Respiration
https://upload.wikimedia.org/wikipedia/commons/0/00/Empty-classroom.jpg

Workshop Outcomes
How can you use immobilized algae cells to
demonstrate the capture of CO2 from the environment
during photosynthesis and the release of CO2 into the
environment during cellular respiration?
How can you take quantitative and qualitative
measurements of photosynthesis and cellular
respiration rates, to illustrate CO2 movement?
How can you engage students in an authentic inquiry
activity that applies concepts relating to photosynthesis
and cellular respiration into one lab?

Setting the Stage for Learning: Make Initial
Observations
 Step 1: Obtain 1 cup with “secret”
solution and 1 straw.
 Step 2: Note the initial color of the
solution.
 Step 3: Blow into the solution using
the straw for 5 seconds.
 Step 4: Note the final color of the
solution.
 Step 5: Discuss observations.

How difficult is it for
your students to make
the connection
between
photosynthesis and
cellular respiration?
Develop questions
about their
relationship?
https://dr282zn36sxxg.cloudfront.net/datastreams/f-
d%3Abb02dabdd2e33b700876335d7476349a0826863a9ce0e73e50b266a8%2BIMAGE%2BIMAGE.1
Student Questions

Our Photosynthesis & Cellular Respiration Kit
helps to bridge the connection!
Kit Design: Applicable to Biology
(Gen Bio -AP) and Environmental
Sciences with a teaching emphasis
on inquiry-based experiments.
Algae Beads: Live algae
(Scenedesmus obliquus) are
immobilized in alginate as “beads”.
The algae can photosynthesize and
respire while beaded.
CO2 Indicator: Colorimetric pH
indicator allows for qualitative and
quantitative data collection.

Algae beads
(~ 2 mm)
Algae beads have a long shelf-life &
require minimal prep!
Algae can be reused for multiple
Experiments!
Algae beads are easy to dispose!
Beads are easy for students to handle
and move!
Algae Beads are AWESOME!

What questions can we ask about
Photosynthesis & Cellular Respiration using
Algae Beads & the CO2 indicator solution?
Think Pair Share
Developing Investigation Questions!

 pH indicator:
 Predictions?
– Light >
– Dark >
CO2 Indicator Solution
CO2 + H2O H2CO3 HCO3
-
+ H+
Atmospheric CO2

Procedure overview
Steps 1-2: Transfer Algae beads
Steps 3-5: Wash Algae beads
Step 6: Add CO2 Indicator to Algae beads (10 min.)
Step 7: Set Algae Beads in light and dark conditions
Step 8: Collect data at 5 minute intervals
Begin to wrap up data collection (20 min.)
Step 9: Interpret results after ~30 minutes
Step 10: Continue to expose Algae beads to
separate conditions and discuss results
Cuvette and cap
CO2 Indicator
Algae beads

Procedure
1. Cut transfer pipette at 250 ul mark
2. Transfer 10 beads to 2 cuvettes labeled dark and light

Procedure
3. Remove excess liquid from cuvette
4. Add 1 ml of distilled water to both cuvettes and incubate for 5 minutes
H2O 1 ml

Procedure
5. Remove water
6. Add 1 ml C02 Indicator to both cuvettes and cap
H2O
1 ml indicator

Procedure
7. Record initial pH / Absorbance for each cuvette and put one cuvette in
the dark (foil) and one in the light with beads spread out
8. Record changes in pH and Absorbance every 5 min

Qualitative and Quantitative Results!
Experiment start Photosynthesis: lights on Respiration: no light
•Red solution indicates
atmospheric CO2
concentration
•Purple solution
indicates CO2
consumption
•Yellow solution
indicates CO2 release

Extensions: Where can we go from here?
 For this investigation, you investigated the
link between photosynthesis and cellular
respiration in algae beads exposed to light
and dark.
 What other environmental
variables might affect
photosynthesis and cellular
respiration?
https://dr282zn36sxxg.cloudfront.net/datastreams/f-
d%3Abb02dabdd2e33b700876335d7476349a0826863a9ce0e73e50b266a8%2BIMAGE%2BIMAGE.1

Lab Overview
Activity (* = Stopping Point) Time required When performed
Equilibrate CO2 Indicator
Activate algae & aliquot CO2 indicator
15-20 min 3 days prior to lab
1 day prior to lab
Lab Investigation #1 & #2
(Microscopy & PS/CR comparison)
30-50 min Day 1 or First Lab
*Store beads up to 2 weeks in refrigerator 10 min After Lab 1
Lab Investigation #3 (Effects of
Light Color on PS rate)
30-50 min Day 2 or Second Lab
*
Lab Investigation #4 (Effects of
Light Intensity on PS rate)
30-50 min Day 3 or Third Lab
*
Lab Investigation #5 or #6
(Temperature & Mini Ecosystem)
30-50 min Day 4 or Fourth Lab

What is inquiry? What did we model?
Levels of Inquiry
(Herron 1972)
Confirmation Students confirm a principle through an activity in
which the results are known in advance
(“cookbook” lab)
Structured Students investigate a teacher-presented
question through a prescribed process
Guided Students in investigate a teacher-presented
question using student-designed/selected
procedures
Open Students investigate questions that are student-
formulated

What are the benefits of inquiry?
Through inquiry, students:
 Ask questions
 Make predictions
 Design plans to investigate answers to the questions
 Apply mathematical routines to analyze data
 Develop and refine testable explanations for
observed phenomena
 Ask new questions for further investigation

Classroom Context & Inquiry:
Dead Zone of the Gulf of Mexico

What questions can we ask about the Dead Zone?
How can we use the Photosynthesis & Cellular
Respiration Kit to investigate these questions it?
Think Pair Share
Developing Investigation Questions!

Questions to consider!
What types of organisms
likely live at the bottom of
the Gulf where the water
is most hypoxic?
What cellular processes
are affected by decreased
oxygen levels?
What environmental
factors can affect the
levels of dissolved oxygen
in the Gulf waters?
http://www.ecy.wa.gov/programs/eap/Nitrogen/Images/eutrophication.png

More questions to consider!
 Phytoplankton (microscopic algae)
are primary producers in the Gulf.
What environmental factors sustain
their growth? What do they
produce in return?
 What is the connection among the
substrates and products of
photosynthesis and cellular
respiration?
 Why are phytoplankton the ultimate
cause of the Dead Zone in the Gulf
of Mexico?

What additional connections can your students
make?
 Evolution of photosynthesis and cellular respiration
 Prokaryotes vs. eukaryotes
 Evolution of chloroplasts and mitochondria
 Endosymbiont hypothesis
 Chemistry (products vs. reactants; equations for
photosynthesis & cellular respiration)
 Anaerobic vs. aerobic environments
 Cellular energetics
 Energetics of ecosystems (producers, consumers)
 Others?

Wrapping Things Up
 Thank you for attending. Please fill
out the workshop survey!
Question! Question!

More information on
this kit
bio-rad.com/algae7
Teaching resources for
THINQ!™ Products
bio-rad.com/ThINQ103
Photosynthesis & Cellular Respiration Kit

 Measuring PS or CR rates in light and
dark environments
– two cuvettes; one exposed to light
one wrapped in foil (dark)
– monitor color every 5-10 min (or take
spectrophotometer readings)
– graph data and note observations
 “Core” lab
– students gain familiarity with handling
algae, using Indicator Color Guides
(or spectrophotometer)
– PS rates by increase in pH (more
purple) or increase in absorbance
– Can “switch” light-dark cuvettes to
see dominance of CR or PS process,
interdependence of PS and CR)
(Cuvette matching courtesy San Luis High School,
San Luis, AZ)
(Light / Dark algae cuvettes courtesy Mills E.
Godwin High School, Richmond, VA)
Product Information – Lab Investigation #2

 Measuring PS or CR rates in light and
dark environments
– two cuvettes; one exposed to light
one wrapped in foil (dark)
 “Core” lab
– students gain familiarity with handling
algae, using Indicator Color Guides
(or spectrophotometer)
– PS rates by increase in pH (more
purple) or increase in absorbance
– Can “switch” light-dark cuvettes to
see dominance of CR or PS process
(Students measured absorbances using a
Spectronic 20 at 550nm by modifying protocol and
placing algae beads in test tubes. Data provided
courtesy St Mark’s School of Texas, Dallas, TX)

 Measuring PS rates vs Light Intensity
– Comparison of PS rates using
transparencies with varying screen
densities (0%, 50%, 85%, 100%)
– use skills and techniques learned
from Lab #2
– Algae can be re-used multiple times
– Intensity filters can be from
transparencies or existing lab supplies
OR reduce light intensity by changing
distance of cuvette to light. (PDF to
print your own colored transparencies
provided)
 Guided/Open Inquiry possibilities
(Data provided courtesy of Red Bank Catholic High
School, Red Bank, NJ)

 Measuring PS rates vs Light Color
– Comparison of PS rates using
colored transparencies (clear, red,
blue, yellow, green)
from Lab #2
– Colored filters can be from
transparencies or existing lab
supplies. (PDF to print your own
colored transparencies provided)
(Students recorded both Vernier Colorimeter
readings at 565nm as well as pH readings from
Indicator Color Guide. Data provided courtesy of
Northfield High School, Northfield, MN)
Green
(absorbance)
Green
(pH)
Clear
(absorbance)
Clear
(pH)
0 minutes -0.002 7.8 0.005 7.8
10 minutes 0.001 7.8 0.055 8.0
20 minutes 0.009 7.6 0.160 8.2
30 minutes 0.010 7.8 0.272 8.2
40 minutes 0.023 7.6 0.390 8.4
Slope, as
calculated using
LoggerPro
0.0005900 -0.004000 0.009870 0.01400

 Mini-Ecosystem of Algae and Snails
– Comparison of PS and CR rates
using a closed environment of algae
(photosynthesizing) and snails
(respiring)
from Lab #2
– variables of light/dark, algae beads,
indicator, snails
Cuvette Labels
LI LIB LIS LIBS DI DIB DIS DIBS
1 ml CO2
indicator
       
10 algae
beads
   
Snails    
Change in CO2 Indicator Process(es) Occurring
LI No change in color No photosynthesis or cellular respiration
LIB Turns purple Photosynthesis by algae beads
LIS Turns yellow Cellular respiration by snails
LIBS Turns purple or turns yellow or no
change in color
Depends on the number of beads and
snails in the cuvette
DI No change in color No photosynthesis or cellular respiration
DIB Turns yellow Cellular respiration by algae beads
DIS Turns yellow Cellular respiration by snails
DIBS Turns yellow Cellular respiration by snails and algae
beads

SPHERE workshop set up
Teacher workstation
 2 x trUView cuvettes
 2 x cuvette caps
 1 x aluminum foil (3x3”)
 2 x 1.5 ml dH2O (in 2 ml microcentrifuge tubes)
or 1 x 3 ml dH2O in 5ml falcon tube
 2 x 1.5 ml CO2 indicator (in 2 ml microcentrifuge
tubes)
 25 x algae beads (activated in 1 ml CO2 indicator
in 2 ml microcentrifuge tubes)
 6 x DPTP
 1 x cuvette rack
 1 x green rack
 1 x scissors
 1 x sharpie
 1 x waste cup
 1 x color indicator
 4 x Protocol and data collection sheets (or hand
out at front)
 Ball point pen (optional)*
 Index card* *for inquiry brainstorming
Common workstation
 4 x lamps
 4 x 60 watt lamps
 1 x power bar
 1 x extensions chord
 1 x smartspec
 1 x trUView cuvette containing equilibrated CO2
indicator
Photo to come

SPHERE Kit: Quick Guide
Steps 4 – 5: Wash the Algae Beads

Steps 6 – 7: Experimental Set-up

Steps 8 - 9: Collect Data

Classroom Context & Inquiry:
Why is what we’re studying important? Providing Inquiry Bait!!
 Gulf of Mexico provides 72% US harvested shrimp, 66%
harvested oysters, and 16% commercial fish. Why is this
important?
 Fertilizer run-off from Midwest farms→ Mississippi River
→ Gulf of Mexico. What elements comprise fertilizer? What are
possible consequences of run-off?
 Waters at the bottom of the Gulf have become hypoxic,
forcing shrimp and other critters to flee to fresher waters
or die. Why must they find a new neighborhood?
Where have all the brown shrimp gone?

 pH indicator:
 Predictions?
– Light > photosynthesis > CO2 consumption > less H+ > pH increases > purple
– Dark > cellular respiration > CO2 production > more H+ > pH decreases > yellow
 pH indicator:
 Predictions?
–Light
–Dark
The CO2 Indicator Solution is Sensitive to pH
CO2 + H2O H2CO3 HCO3
-
+ H+
PhotosynthesisRespiration Atmospheric CO2
CO2 in solution

Curriculum and Training Specialists
Leigh Brown
leigh_brown@bio-rad.com
Sherri Andrews, Ph.D.
sherri_andrews@bio-rad.com
Damon Tighe
damon_tighe@bio-rad.com
Tamica Stubbs
Tamica_stubbs@bio-rad.com

Got Protein? Kit – Core Content Alignment
Scientific Inquiry
•Quantitation of milk proteins
•Use of a spectrophotometer
•Use of experimental controls
•Creation and use of a standard curve
Chemistry of Life
•Chemical and physical properties of
proteins
•Biophotonics and Beer’s Law
•Protein chemistry and structure
•Chemistry of dye molecules
•Properties of chemical bonds
Cell and Molecular Biology
•Protein production and secretion
•Nutrition and immunity
Environmental and Health Science
•Lactose
•Mineral and vitamin requirements
Evolution
•Function of milk proteins
•Role of milk in reproductive success of
organisms
•Natural Selection
Genetics
•DNA>RNA>protein>trait
•Biochemistry of milk

photosynthesis and cellular respiration

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