Experiment Worksheets- Exp 3,4,5

Algae Bead Module:  Lessons, Projects, and Experiments

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Experiments:  Algae Beads

General NGSS Projects for Photosynthesis, Respiration, and Algal Physiology

Aligned for NGSS Standards:

HS-LS1-5	Use a model to illustrate how photosynthesis transforms light energy into stored chemical energy.
HS-LS1-6	Construct and revise an explanation based on evidence for how carbon, hydrogen, and oxygen from sugar molecules may combine with other elements to form amino acids and/or other large carbon-based molecules.
HS-LS1-7	Use a model to illustrate that cellular respiration is a chemical process whereby the bonds of food molecules and oxygen molecules are broken and the bonds in new compounds are formed resulting in a net transfer of energy.
HS-LS2-5	Develop a model to illustrate the role of photosynthesis and cellular respiration in the cycling of carbon among the biosphere, atmosphere, hydrosphere, and geosphere.
HS-PS1-5	Apply scientific principles and evidence to provide an explanation about the effects of changing the temperature or concentration of the reacting particles on the rate at which a reaction occurs.
HS-PS1-6	Refine the design of a chemical system by specifying a change in conditions that would produce increased amounts of products at equilibrium.
HS-LS4-4	Construct an explanation based on evidence for how natural selection leads to adaptation of populations.

Copyright 2020 by Algae Research and Supply, Inc.  Carlsbad CA.  All rights reserved.  

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Algae Research and Supply, Inc.

Carlsbad, CA 92008

AlgaeResearchSupply.com

Info@AlgaeResearchSupply.com

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Surface Area: Volume and Algal Photosynthesis
(Algae Bead Experiment 3 of 5)

Project Summary: This experiment aims to test the effects of surface area to volume ratio (SA:V) on rates of algal photosynthesis. Students will be comparing smashed algae beads to whole algae beads to confirm the relationship between SA:V and efficient uptake. Although we are not technically altering the shape of the algal cells themselves, the alginate bead facilitates the transfer of carbon dioxide and carbonate to the encased cells. Altering the SA:V of the beads is linked to the resident algae's resulting productivity within the beads. Time Estimates: 45 minutes (depending on time intervals) Learning Outcomes:  I can collect and analyze data safely using the appropriate lab materials. I can compare smashed algae beads to whole algae beads to determine and justify the relationship between SA:V and efficient uptake Classroom Prep: Divide class into lab groups if desired. See the materials list for the required components Videos: Vocabulary: Surface Area to Volume ratio

Background

Large organisms like mammals and other vertebrates have a specialized orifice to consume their energy choice, be it grass or meat. This mouth is the most efficient way to consume food for these larger lifeforms. As we zoom into the microbial world, however, other methods begin to appear. The most obvious is diffusion through the membrane constituting the cell itself. This transport's efficiency is mediated by the organisms' Surface Area: Volume ratio (SA:V). In this case, the surface area describes the amount of membrane available for transport, and the volume describes the cavity in which items are transported.

As an organism's SA:V increases, the efficiency with which an organism can transport products through its membrane increases. This flows logically, as there is more area available to transport items into a relatively smaller cavity. There are many ways that an organism can increase its SA:V. The easiest is just being smaller overall, as little spherical bacteria are more efficient at transporting products than a larger spherical eukaryote. If being small is not an option, you can fold your membrane into ridges that do not affect your overall volume but increase your surface area. This effect is in play in the human intestinal tract, with ridges called villi and microvilli providing more surface area to uptake digested nutrients than a comparable smooth surface.

This experiment aims to test the effects of variable SA:V on rates of algal photosynthesis. Students will be comparing smashed algae beads to whole algae beads to confirm the relationship between SA:V and efficient uptake. Although we are not technically altering the shape of the algal cells themselves, the alginate bead facilitates the transfer of carbon dioxide and carbonate to the encased cells. Altering the SA:V of the beads is linked to the resident algae's resulting productivity within the beads.  

Materials

• 5-100 vials of ARS Algae Beads in pH indicator  (20 is about perfect)

• Make them yourself, or buy them directly from us:
• Make your own algae beads kit, (AB-DIY-01000)
• Buy our Ready-to-Go Algae Beads (AB-RTG-0030)

• A finger to smash the beads        
• A Light source
• Light meter, (See Experiment 1 for information about Google Science Journal)
• Length measuring device

• Calipers would be brilliant (why- they are another tool to teach the students to use)
• Ruler, metric

• Any container to hold the indicator and beads while you measure them.
• Goggles
• Scale (optional)

Tips and Considerations

• (optional) If you want to get more data, measure the mass of each bead. This means you have to have an analytical balance. If you don’t have this, you ASSUME that the beads are all equal in mass (they should be pretty darn close).
• If the smashed bead tends to fall apart, let the algae bead sit for 10-15 minutes before smushing and they may form into a better shape.

Procedure

1. Determine how many samples of smashed and unsmashed algae beads you want to test; three or more is optimal. Remove them from the tube and record their diameter, then return the unsmashed beads.
2. Smash an equal number of beads between your finger and thumb. Measure the diameter of each disk you create, then return the beads to their tubes.

1. To determine the sphere’s surface area, divide the diameter in half to get the radius (r).  Then use the formula 4πr2.  
2. The formula for the surface area of a disk is πr2, be sure to multiply this by 2 to account for the bottom and top of the disk (if it is flat, you can discount the edge of the disk).

3. Set up a light source and arrange the tubes of smashed and unsmashed beads at an equal distance. At set time intervals (every few minutes), record the colorimetric pH using the provided scale. Plot the data on the graph paper provided.

1. You may need to shake the smashed beads in case they settle on the bottom of the tube.

Worksheet

Hypothesis: Based on the smashed and unsmashed beads’ surface area calculations, which do you think will be most photosynthetically efficient? Why?

Variables: Variables: What is our independent (manipulated) variable? Which is our dependent (responding) variable? Which variables are controlled across treatments? Respond below.

Data

UNSMASHED
Sample #	Surface area	Mass	pH at T=0’	pH at Time =	pH at Time =	pH at Time =	pH at Time =
1
2
3

SMASHED
Sample #	Surface area	Mass	pH at T=0’	pH at Time =	pH at Time =	pH at Time =	pH at Time =
1
2
3

Below graph the pH of each tube over time.

Analysis/Conclusion

Based on your data, what differences are there in the rate of photosynthesis between the two types of beads?

Restate your hypothesis. Was your hypothesis correct? Which treatment (smashed or unsmashed) resulted in the highest levels of photosynthesis? Does this conform with the SA:V theory? Why or why not?

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CER Rubric

		Check your work!
Claim – a conclusion that answers the original question		Scientifically accurate Completely answers the question Common inaccurate claim(s) are clearly addressed.
Evidence – scientific data that supports the claim		The data are scientifically appropriate to support the claim. The data are thorough and convincing – enough details and evidence provided. Proper units are used in data. Shows with evidence why alternate claims do not work
Reasoning – a justification that links the claim and evidence		Reasoning clearly links evidence to claim Shows why the data count as evidence by using appropriate scientific principles There are sufficient scientific principles to make links clear between claim and evidence

Temperature and Algal Photosynthesis
(Algae Bead Experiment 4 of 5)

Project Summary: The goal of this experiment is to determine the optimal temperature for effective algal photosynthesis. To do this, you will be exposing algae to various temperatures and recording the rate of photosynthesis resulting from these treatments. Time Estimates: 45 minutes (depending on time intervals) Learning Outcomes:  I can determine the optimal temperature for effective algal photosynthesis and justify based on the data collected. I can collect and analyze data safely using the appropriate lab materials. Classroom Prep: Divide class into lab groups if desired. See the materials list for the required components Videos: Vocabulary: kinetics, denature,

Background

        It is fairly evident from our life experience that temperature can be a significant factor in a biological response. Consider, for instance, how much harder it is to run a mile without warming up in a snowstorm vs. doing the same on a warm, pleasant day. These effects are similar in single-celled organisms like algae. The science behind these effects is called kinetics.

Chemical reactions have an optimal temperature at which they will perform most effectively. This is because most cells’ reactions are mediated by enzymes: proteins that lower the amount of energy necessary to complete them. These proteins can lose effectiveness and denature (or unravel themselves) when temperatures get too high, or freeze up and stick when the temperature gets too low. If you’ve ever cooked an egg, the reason that the contents of the shell change color and consistency are due to the denaturation of proteins. Fevers in mammals can be dangerous when they get too high because their enzymes begin malfunctioning and denaturing.

        Most, if not all, photosynthesis steps are mediated by enzymes, which like all others, have an optimal temperature. The goal of this experiment is to determine the optimal temperature for effective algal photosynthesis. To do this, you will be exposing algae to various temperatures and recording photosynthetic responses resulting from these treatments.  

Materials

• Goggles
• 5-100 vials of ARS Algae Beads in pH indicator  (20 is about perfect)

• Make them yourself, or buy them directly from us:
• Make your own algae beads kit, (AB-DIY-01000)
• Buy our Ready-to-Go Algae Beads (AB-RTG-0030)

• Temperature control options:

• Ice Bath (What size bucket will they need? How much ice/ water?)
• Refrigerator
• Heating pads/hot plate with a magnetic stirrer

• Thermometer

• IR ones are our favorites.

Tips and Considerations

• We should supply an equal amount of light to each tube.  The experimental setup will vary based on the light you have, as well as the heat / cold source.
• Consider the fact that your light source will also give off heat at a certain distance. Try to place the light in such a way that it does not meaningfully contribute to the temperature experienced by the tubes.

• If this is unavoidable, take it into account when adjusting the temperature source.

• The number of different temperatures you use as treatments is dependent on how many temperature control devices you have. Chlorella vulgaris has an optimal temperature range of between 25 and 28 degrees Celsius. Include this temperature as a baseline for growth, and then try to find a temperature below and above this, at the very least. Make as many temperature treatments as you would like; more data is always advantageous.

Procedure

1. Set up a light source in one of the ways mentioned in the Tips and Considerations section.
2. Set up your temperature source. If you have a temperature-controlled system like a combination heater/magnetic stir bar turner, only one will be necessary. If you cannot electronically or mechanically control temperature, you will need multiple water baths at different temperatures. Monitor these baths with a thermometer and do your best to keep the temperature constant throughout the experiment.
3. Place the tubes in the water baths/temperature control devices. At set time intervals, record pH with the colorimetric scale. Plot the data on the provided graph paper.

Worksheet

Hypothesis: Make a prediction. At what temperature do you expect photosynthesis to cease completely? At what temperature do you expect photosynthesis to do the best?

Theoretically, do you think these inhibitory temperatures would be different if we were to use different algae species in our algae beads? Why or why not?

 

Variables: What is our independent (manipulated) variable? Which is our dependent (responding) variable? Which variables are controlled across treatments? Respond below.

Data

Tube	Temp (°C)	Light Intensity (eV)	pH at T=0’	pH at Time =	pH at Time =	pH at Time =	pH at Time =	pH at Time =
T1
T2
T3
T4
T5

Below graph the data for each tube over time.

Analysis/Conclusion

Based on your data, How did each treatment affect photosynthesis?

Restate your hypothesis, was your prediction correct? Based on your data, does temperature affect photosynthesis? Why or why not?

Extending Questions

Do you think these effects would occur at different temperatures with different species? Why or why not?

Do some research on polar vs tropical microalgae. What are some similarities and differences?

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CER Rubric

		Check your work!
Claim – a conclusion that answers the original question		Scientifically accurate Completely answers the question Common inaccurate claim(s) are clearly addressed.
Evidence – scientific data that supports the claim		The data are scientifically appropriate to support the claim. The data are thorough and convincing – enough details and evidence provided. Proper units are used in data. Shows with evidence why alternate claims do not work
Reasoning – a justification that links the claim and evidence		Reasoning clearly links evidence to claim Shows why the data count as evidence by using appropriate scientific principles There are sufficient scientific principles to make links clear between claim and evidence

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Photopigment Extraction and Analysis
(Algae Bead Experiment 5 of 5)

Project Summary: The goal of this experiment is to perform a fundamental spectral analysis of the photopigments possessed by Chlorella vulgaris, the algae encased within our alginate beads. In a laboratory, this is achieved with a variety of highly complicated and expensive machines. In this experiment, we will be using chromatography paper or a coffee filter, which executes roughly the same function. We will split the solution of various pigments into the component wavelengths that they absorb, which will serve to break them apart from each other so that we can make educated guesses about which molecules C. vulgaris uses to harvest light. Time Estimates:       Learning Outcomes:  I can perform a spectral analysis of the photopigments possessed by Chlorella vulgaris I can determine the photopigments in Chlorella vulgaris and justify based on the data collected. I can collect and analyze data safely using the appropriate lab materials. Classroom Prep: Divide class into lab groups if desired. See the materials list for the required components Videos: Vocabulary: Photopigment, isomerize, spectral analysis

Background

        Photopigments “isomerize,” or change shape, when a photon of light strikes the structure. The specific structure of each photopigment discriminates the wavelength of light that forces this isomerization. This same concept is in play in our eyes’ cones, with three types of photopigments undergoing isomerization to indicate impingement of various wavelengths of light. Mammalian color blindness is due to the loss or relative low presence of one or more of these photopigments.

        In algae, varying photopigments’ structure amounts to a molecular arms race allowing more efficient harvesting of light in advantageous conditions. Take, for example, the structure of divinyl chlorophyll a (DV-chl-a) versus divinyl chlorophyll b (DV-chl-b), shown^[1]. As we can see, the only change in structure occurs in the top right corner, with DV-Chl-a lacking the double-bonded oxygen possessed by DV-Chl b. This simple change captures blue light better than red light and allows the cyanobacterium that possesses DC-Chl b to live at deeper depths when red light has disappeared through water and only blue light remains.

        The goal of this experiment is to perform a fundamental spectral analysis of the photopigments possessed by Chlorella vulgaris, the algae encased within our alginate beads. In a laboratory, this is achieved with a variety of highly complicated and expensive machines. In this experiment, we will be using chromatography paper or a coffee filter, which executes roughly the same function. We will split the solution of various pigments into the component wavelengths that they absorb, which will serve to break them apart from each other so that we can make educated guesses about which molecules C. vulgaris uses to harvest light.

Materials

• ~20 ARS Algae Beads

• ABCv from AlgaeResearchSupply.com
• Make them yourself, from scratch or from a kit:

• Make your own algae beads kit, (AB-DIY-01000)
• Buy our Ready-to-Go Algae Beads (AB-RTG-0030)

• A finger to smash the beads
• Pipette
• Organic solvent  (~30ml)

• Acetone  (4-parts)
• Isopropyl alcohol (1-part)

• Container to extract the pigments,  you can use the snap-cap vials.
• Chromatography paper or coffee filter paper (2x 10cm)
• Plant leaf

• Standard issue plant leaf or flower pedal.  You may want to mash it with the back of a spoon to get the cells to open up for extraction.  
• Experiment with flowers (optional; they may have the same pigments but in different concentrations as both the leaf and the algae, and flowers are pretty)

Tips and Considerations

• CAUTION: Acetone is volatile and harmful when inhaled, among other dangers. Carefully read its Material Safety Data Sheet (MSDS^[2]) before proceeding, and always wear appropriate PPE.
• Try to have the algae and plant pigment extract be equally dense on the chromatography paper.  It makes for better comparisons.  
• You can hang the filter paper from the top of a jar or cup with a toothpick or pencil letting the tip of the paper touch the solvent.

Procedure 

Pigment extraction:

1. Pinch to flatten a few algae beads and soak them with acetone/alcohol solution.  Do the same with some green leaves from your yard. The goal is to get the dark colors out of the plant material. You may want to leave them to soak in the dark overnight.  

Chromatography:  

1. Using coffee filter paper (or chromatography paper), cut several identical strips roughly 2cm by 10cm. Gently, mark a line in pencil ~2cm from one of the sides.
2. Carefully drip the extracted pigments using the pipette over and over onto the 2cm line. Take your time, the smaller and darker the dot, the more resolution you will get in the chromatography.  
3. Now that the extracted pigments have been “loaded” onto the paper, a solvent will force the pigments apart

1. Best option: a chromatography jar that you can dip the paper into, stopping at the “x” (see image below).
2. Good option: applying the solvent to the “x” dropwise for ~10 minutes

Chlorophyll-b - olive green

Chlorophyll-a - blue green faint yellow / orange  

Carotenes - faint orange/yellow

Xanthophylls - yellow

Image: (Top) Idealized chromatography paper layout with a green pigment spot approximately 2cm from the chromatography paper (coffee filter). The “x” marks the place where you will drop the solvent to drive the pigments apart. (Bottom) Idealized photopigment separation after solvent addition.  

Worksheet

Hypothesis: Research the photopigment composition of Chlorella vulgaris. Using that information, make an educated guess about what the chromatography paper will look like upon separation.

Data

Algae Beads

Line /  Pigment	Distance from bottom	Color observed	Probable pigment
Pigment location	2.0cm from bottom	Not applicable	Not applicable
1. Closest to bottom
2.
3.
4.
5. Solvent frontline		Not applicable	Not applicable

Terrestrial plant leaf

Line /  Pigment	Distance from bottom	Color observed	Probable pigment
Pigment location	2.0cm from bottom	Not applicable	Not applicable
1. Closest to bottom
2.
3.
4.
5. Solvent frontline		Not applicable	Not applicable

Sketch your chromatograms, labeling the distance traveled from the origin as well as your assigned photopigment identity

Calculate the retention factor for each photopigment observed.

(Rf = distance pigment traveled ÷ distance solvent traveled)

Analysis/Conclusion

Why do some of the photopigments travel farther down the paper than others?

Were you able to successfully identify all the pigments your research suggested would be present in Chlorella vulgaris? Were there some that you did not extract? Why might this be?  

Using the retention factor information from the algae, the terrestrial plant leaf, and a flower petal, are there any similar pigments?  Why do you think that is?

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CER Rubric

		Check your work!
Claim – a conclusion that answers the original question		Scientifically accurate Completely answers the question Common inaccurate claim(s) are clearly addressed.
Evidence – scientific data that supports the claim		The data are scientifically appropriate to support the claim. The data are thorough and convincing – enough details and evidence provided. Proper units are used in data. Shows with evidence why alternate claims do not work
Reasoning – a justification that links the claim and evidence		Reasoning clearly links evidence to claim Shows why the data count as evidence by using appropriate scientific principles There are sufficient scientific principles to make links clear between claim and evidence

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