Chapter 1. Photosynthesis Lab

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Photosynthesis Lab

Photosynthesis is a biochemical process that makes all life on Earth possible: without it, nothing living would exist. It makes the oxygen we breathe, the energy we use, and the carbon-containing compounds that make life possible. It is such a powerful force that humankind would like to harness it for our own goals. Your task today is to design and test an air filter that uses photosynthetic organisms to clean harmful chemicals out of the air we breathe. If you are successful, your air filter could be used in tight, confining areas with little or no natural breathing air available—on the international space station, for instance, or on deep-sea submersibles. NASA is waiting to hear the results of your experiments, so let’s get started!

First, you’ll have to determine a suitable photosynthetic organism to use in your filter. We have several different options to choose from. Next, you’ll have to determine the optimum environment for this organism: what chemicals does it need to function? What light source? What by-products will it produce? Are there any other functions it can provide besides just filtering the air? You’ll also need to document how it works at the cellular level, so we’ll use some microscopy to analyze the process inside the cell and chloroplast. Lastly, since it is a photosynthetic life form, it makes its own food from light energy. You’ll test whether maybe you could harvest some of that food. Ready to begin?

1.1 Background

Some things are non-negotiable requirements for human life: water, food, and oxygen immediately come to mind. We can live for days without food and water, but if our oxygen supply is cut off, we only have a few minutes. Access to air limits where we can go: for example, astronauts can only go into space if they bring their own air supply, and we can only explore the deep sea if we are inside a submarine or submersible.

What if we could change that? Science fiction writers often describe a process that they call “terraforming.” This means transforming a planet so it resembles earth, including an oxygen atmosphere. Could this ever be possible? Only time will tell.

But let’s start a little smaller. In this lab, your goal is to develop a device that can create breathable air in space or the deep sea. Humans exhale carbon dioxide, and if the levels get too high, heart rate, breathing and blood pressure go up. A person could go into a coma and even die. So your device needs to remove carbon dioxide from air. And while you’re at it, could it create other useful substances, like food?

To be able to do these things, you will need to understand the most important process on earth. Photosynthesis is our source for both oxygen and food. The word photosynthesis defines itself. “Photo” means light, and “synthesis” means building or creating something. The process of photosynthesis uses the energy of sunlight to create sugars. Let’s look at how it works.

(Ins Fig 1. This figure will show a very simplified diagram of photosynthesis. Emphasis is on the inputs of light energy, carbon dioxide and water and the outputs of glucose and oxygen.)

Photosynthesis is a very complex process involving many chemical reactions. The big picture is often summarized in one equation:

Or, in words:

Carbon dioxide + water (light)→ oxygen + sugar

What does this equation tell us? Photosynthetic organisms take in water (H2O) and carbon dioxide (CO2). They also absorb light energy from the sun (or other artificial light sources, for example grow lights). Inside the cells of these organisms, complex chemical reactions convert the water and carbon dioxide into carbohydrates (C6H12O6, glucose) and oxygen gas (O2). The oxygen gas is released out of the cell, but the carbohydrates can be used to make a variety of molecules that a plant needs, such as sucrose, starch, and cellulose. The plant can also use glucose as an energy source, just as our cells do.

There are two main stages of photosynthesis.

  • The light reactions are the stage in which chlorophyll absorbs sunlight energy. Some of the energy that is harvested is stored in high-energy electrons, while some of it is stored in adenosine triphosphate (ATP). During this stage, the water molecules will be split apart to provide a continuous supply of electrons. When water is split apart, oxygen gas is formed.
  • The Calvin cycle is the stage in which carbohydrates are formed. All of the energy stored in the high-energy electrons and ATP is used to convert CO2 into larger carbohydrates. Eventually, these molecules will be used by the plant to make sugars (e.g. glucose) and other important molecules.

Which organisms can photosynthesize?

Organisms that can photosynthesize are often called producers because they are producing their own food—they don’t need to eat other organisms. This is in contrast to consumers, who must eat other organisms for energy. Bacteria were the original producers, and they evolved the process of photosynthesis. One group of bacteria, the cyanobacteria, appears to be the ancestors of the chloroplast. The chloroplast is the subcellular structure where photosynthesis takes place in algae and land plants.

There are a wide variety of algae. They vary in size, from single cells to giant kelps. And they vary in color, from green to red to golden to brown. They all contain chloroplasts and chlorophyll. However, some algae contain pigments in addition to chlorophyll that they use for photosynthesis. These pigments give the red, golden, and brown algae their color. In this lab, we are going to focus on green algae and land plants, because their method of photosynthesis uses only chlorophyll. Therefore, for our purposes today, producers must be green.

(Ins. Fig 2. This figure should be a triptych. One panel shows cyanobacteria, one shows green algae, and one shows a land plant. Algae should include single-celled and multicellular ones (seaweeds), while the land plant should be something big to emphasize the difference between them and the algae)

How does photosynthesis work?

First, you have to be able to capture sunlight energy. This is the job of chlorophyll. Chlorophylls are pigments, colored molecules that absorb light. There are several different types of chlorophyll, but they all are involved in absorbing sunlight. The wavelengths of light that are used for photosynthesis are the ones that are visible to us: the colors of the rainbow. Plants are green because chlorophyll is green. And chlorophyll is green because it does not absorb green light. Instead it transmits or reflects it. Chlorophyll is best at absorbing violet, blue, and red light. These wavelengths of light provide most of the energy used in photosynthesis.

(Ins Fig 3. This figure will show the absorption spectrum of chlorophyll, demonstrating that it absorbs violet, blue and red wavelengths the best.

Second, you need carbon dioxide. This is not hard to find. There is always carbon dioxide in the air for plants that live on land. And for plants and algae that live in water, there is carbon dioxide dissolved in water.

Third, you need water. Again, this is not usually hard to find. In desert environments, where water is scarce, plants have adaptations that allow them to conserve as much water as possible.

Photosynthesis is a long process involving many chemical reactions. But at the end of the process, the carbon dioxide molecules have been combined into a larger molecule, glucose. The water molecules have been split apart. When the hydrogen atoms are removed from a water molecule, what is left is oxygen.

So to summarize, photosynthesis starts with: sunlight, chlorophyll, water, and carbon dioxide. It ends with: glucose and oxygen.

What is the point of photosynthesis?

Why do producers spend time and effort on photosynthesis? Well, they need the products. Remember, they are called producers because they are producing their own food (sugar) and oxygen. So they are pretty much self-sufficient.

But that’s not what makes photosynthesis the most important process on earth. Consumers also get their food and oxygen from photosynthesis. The oxygen in the air we breathe comes from photosynthesis. And when a consumer eats a producer, it can use some of the energy stored in the producer’s cells for its own energy needs.

This is how a food web develops. A food web is a description of who eats what in a particular ecosystem. The producers are not eating anybody, because they make their own food. They are always at the base of a food web, supplying food for everybody else. Next, the primary consumers are the herbivores, animals that eat producers. The secondary consumers are the carnivores, animals that eat herbivores. So even though the carnivores don’t eat producers, the energy they get from their food ultimately came from a producer. As your final activity in today’s lab, you will look at how energy is transferred from one organism to another, and you will see that it takes a lot of producers to feed the world!

(Ins. Fig 4 This figure will be a very simple food web, with producers and consumers labeled. Since we are using algae, an aquatic food web will be best because it will include them. First one is really nice! See document for example)

1.2 Pre-Lab Quiz

Before we can being to design the filter, you’ll have to understand the background material covering photosynthesis—what types of organisms can do it, what it requires, what it produces, etc. Make sure you read the background material thoroughly, and then answer the following questions.

Question 1.1

Indicate if each of the following items is required by photosynthesis or produced by photosynthesis.

A. water pbyqoLGGJYjAeG8a+kJQfRICrWrvIvaE

B. sunlight pbyqoLGGJYjAeG8a+kJQfRICrWrvIvaE

C. carbon dioxide pbyqoLGGJYjAeG8a+kJQfRICrWrvIvaE

D. sugar duMODbHVGET8Ujlf2v/QK8xB+0swPltz

E. oxygen duMODbHVGET8Ujlf2v/QK8xB+0swPltz

Water, sunlight, and carbon dioxide are required by photosynthesis, whereas sugar and oxygen are produced by photosynthesis.
Water, sunlight, and carbon dioxide are required by photosynthesis, whereas sugar and oxygen are produced by photosynthesis.

Question 1.2

Determine if each of the following statements is True or False.

A. All wavelengths of light are equally effective for photosynthesis. IkLyhbbYRLnR0DDUHGa+YA==

B. Oxygen is released from photosynthetic organisms. l/z1Yl7oaTd5t5aAlzVI9g==

C. Photosynthesis removes carbon dioxide from the air. l/z1Yl7oaTd5t5aAlzVI9g==

D. In eukaryotes, photosynthesis occurs within the chloroplast. l/z1Yl7oaTd5t5aAlzVI9g==

E. Only land-dwelling plants can perform photosynthesis. IkLyhbbYRLnR0DDUHGa+YA==

It is True that: Oxygen is released from photosynthetic organisms; photosynthesis removes carbon dioxide from the air; and photosynthesis occurs within the chloroplast in eukaryotes. The other statements are False.
It is True that: Oxygen is released from photosynthetic organisms; photosynthesis removes carbon dioxide from the air; and photosynthesis occurs within the chloroplast in eukaryotes. The other statements are False.

Question 1.3

Choose the term that best describes each organism below: Producer or Consumer.

A. E05vs9+53wbEeZCOly7sZScLMKodNx7U

B. stvG1tQqBprecXQWwUZceeIhmkBtv/qg

C. E05vs9+53wbEeZCOly7sZScLMKodNx7U

D. E05vs9+53wbEeZCOly7sZScLMKodNx7U

E. stvG1tQqBprecXQWwUZceeIhmkBtv/qg

Items A, C, and D are producers, while B and E are consumers.
Items A, C, and D are producers, while B and E are consumers.

Question 1.4

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Correct. Plants appear green because they absorb wavelengths of red and blue light while reflecting green light.
Sorry. Plants appear green because they absorb wavelengths of red and blue light while reflecting green light.

Question 1.5

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Correct. Photosynthesis provides both food and oxygen to consumers.
Photosynthesis provides both food and oxygen to consumers.

Question 1.6

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Correct. The energy absorbed during the light reactions is stored in ATP and high-energy electrons.
Incorrect. The energy absorbed during the light reactions is stored in ATP and high-energy electrons.

Question 1.7

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Correct. The energy absorbed during the light reactions of photosynthesis is stored in various carbohydrates during the dark reactions.
Incorrect. The energy absorbed during the light reactions of photosynthesis is stored in various carbohydrates during the dark reactions.

1.3 Experiment Notebook

Developers: sections 1.3.1 - 1.3.4 should be smaller tabs beneath the main "Experiments" tab.

Section 1.3.1 Photosynthetic Organisms

First, we’ll need to find the ideal organism to use in our bio-filter. I’ve taken us to a wetlands environment containing a variety of photosynthetic producers and non-photosynthetic consumers. Your job is to collect a variety of different living organisms for analysis in the lab.

Collect six different samples by clicking living organisms you find in this environment. Once you find all six, we’ll travel back to the lab so you can analyze them.

Question

What six things did you collect from the environment? Select all that apply.

bI0LPa9lfHQ+dYqk Fish

wCfH0QtRgXJ8o+c+ Alligator

bI0LPa9lfHQ+dYqk Pond Water

wCfH0QtRgXJ8o+c+ Rain water

bI0LPa9lfHQ+dYqk Aquatic (Water) plants

bI0LPa9lfHQ+dYqk Pond scum/algae

bI0LPa9lfHQ+dYqk Duck

wCfH0QtRgXJ8o+c+ Bald Eagle

bI0LPa9lfHQ+dYqk Terrestrial (Land) plants

wCfH0QtRgXJ8o+c+ Moss

Right. You collected: a duck, a fish, pond water, aquatic plants, pond scum/algae, and terrestrial plants.
No. Remember, you collected: a duck, a fish, pond water, aquatic plants, pond scum/algae, and terrestrial plants.

Question

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Now that you've collected your six samples, we’ll use a carbon dioxide (CO2) chamber in the lab to measure the amount of photosynthesis occurring in each of the samples you’ve collected. However, before you can test your samples, you will have to run some controls to make sure the equipment in functioning correctly.

We will use two controls for this experiment: an empty chamber and a jar of sterilized water. The sterilized water has been heated to kill off any microorganisms; there is nothing living in the water.

Question 1.8

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Okay. We'll see if your expectations are correct soon.

Question 1.9

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Question 1.10

8bP3Ir7MqFR4MFH7f8fa0MRGQAfOm+//AEEjED5Ht9QIcBS6u4ECqYfCvp8xsMC7RGcxLZApLi47tTBFkF76a8VtIWxtrDhHqsx/mNsiToES18B+czFHuX2FjqFJM87zjTxZLK9rtd3ixSOY9haqnJyX7DfsidLvX8Dg6+lfB+H36XQZ
Okay. We'll see if your expectations are correct soon.
Incorrect.

Question 1.11

TfCnOsnPdufGUJlsHib+5CSHPQWo6hayWri58dHdJW3RxaHzWqaIMcBc/dIWR/yU

To run the controlled experiments in the lab, you will either click the “test empty chamber” button (for the empty chamber control) or click and drag the jar of sterilized water to the CO2 chamber. The chamber will automatically fill with 0.5% CO2 gas.

Question 1.12

yC6LamC03+Tag5fIIU25Ycn6R24f6fEOUVds6CfZHekcTDv7Sqrnus1B/1ZTQV1QXClV7a8gSQPXYOKcPbTxA6fdwlrphMIbtzCIZo86sUQYwiBWk+ez49qwAPzO6CFhbqKUk2R+9IAguuLQLuo7Yl77/oS1kUeLN9WeHTYCAdQOwXsdFnoNPeYqONVOGu0SfQny5ilGDsp00fKerQbjRXPC0rQNrSxup4FarD9mYAjUmKXvzgj2iy/IzOvoDCkGDGJFNuTeVQboXvUj3wT6/ldgxiKz0NkUvk5kmuTHKINa7qRkDXjoR/BnPwtz4Z2YgQv2iHB8PfVJzMuuqT9YYpzaRHvYgRnWM+cOsAr9ixQpXv3n1HK+dueGJiYSjEn1Vk0InOoys84tk4A5AfI2f/13AKswv1qQZ7SkY/jM0f7aWDKB96u2VIYlAZssjx+SDI6m210GtxesyYEx
Okay. We'll see if your prediction is correct soon.
Incorrect.

Question 1.13

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Now that you know the machine is functioning correctly, we can use it to determine if the specimens we collected are photosynthetic.

To run the next experiment, you will return to the lab (in just a moment) and click and drag any of the specimens to the CO2 chamber. The chamber will automatically fill with 0.5% CO2 gas.

But first, think about the gases used and produced by photosynthesis.

Question 1.14

OXK0SmbH8mPJ9tk8dytSjY8PRlAmoACQzni03ivTtu6WbtuL1eGukYWcdj87PYDvRSoqAVWwwLs/6GSDh+wRSyizJRhosKEZRjdiDNuw568+LjHxOt70dV1nFSugDgx7eaWpuEKD6XhDNESwb2DKh88NTSuMXEXBIzkU06NAYhFFv+Ih98zdsZ9HNaOl3Ghv96U+5yR0KllZJ0I9BA2DDn6zARKZnUlrK5WGNAX89H/s+WK8VkRoIgfzlWDVpWk5s13uHIw3cVql1P64yNsyYHaBWQToUje1SHKa6NvZO1dqhbF6zmzuk+z9uVCz8zn+O9nd12UDbB+l7zfF+BkcD1Q2a68wE4Gp1NjMWTF3Y54=
Okay. We'll see if your prediction is correct in a moment.
Incorrect.

Question 1.15

TfCnOsnPdufGUJlsHib+5CSHPQWo6hayWri58dHdJW3RxaHzWqaIMcBc/dIWR/yU

Question 1.16

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
Okay. We'll test your prediction in just a moment.
Incorrect.

Question 1.17

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Question 1.18

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Now, let’s go back to the lab and test whether or not your predictions are correct.

Now that you have examined all six of the samples you collected from the wetlands (and all four types of microorganisms in the pond water), answer the questions below.

Question 1.19

Use the drop-down menus to indicate which of the samples were capable of photosynthesis and which were not.

A. Duck: RTzin41e1M7OPsPr9NV+gCbz/NMYAPttXgy8Jwc7VRA6H7TqvovPvQ==

B. Fish: RTzin41e1M7OPsPr9NV+gCbz/NMYAPttXgy8Jwc7VRA6H7TqvovPvQ==

C. Pond Water: kHrUah65I9rnas1YJg6wvYeOaUfTItTWMxq9PSzDfrbk9Fl3oQK+pq/Ja/4U/wJ2Q2z6Vw==

D. Pond Scum/Algae: 10y3/o6u9iLI3hRPLn15E7SM40UwHbEH8uK/F1Khhtec7W6fz/G7JA==

E. Aquatic Plants: 10y3/o6u9iLI3hRPLn15E7SM40UwHbEH8uK/F1Khhtec7W6fz/G7JA==

F. Terrestrial Plants: 10y3/o6u9iLI3hRPLn15E7SM40UwHbEH8uK/F1Khhtec7W6fz/G7JA==

All of the items we collected, with the exception of the duck and the fish, were photosynthetic or mostly photosynthetic.
All of the items we collected, with the exception of the duck and the fish, were photosynthetic or mostly photosynthetic.

Question 1.20

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Question 1.21

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Correct. Chlorophyll was found in all of the photosynthetic organisms.
Incorrect. Chlorophyll was found in all of the photosynthetic organisms.

Question 1.22

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Correct. The pond scum/algae photosynthesized the fastest of all the specimens.
No. The pond scum/algae photosynthesized the fastest of all the specimens.

Here’s what you hypothesized the results would be at the very beginning of the experiment:

Recorded response from earlier in Section 2 displayed here.

Question 1.23

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Below are several other living organisms that can be found in a variety of environments:

Question 1.24

Of these four, which do you think would be photosynthetic? Select ALL the possible photosynthetic organism(s).

wCfH0QtRgXJ8o+c+ Red cage fungus

bI0LPa9lfHQ+dYqk Kelp

wCfH0QtRgXJ8o+c+ Indian pipe

bI0LPa9lfHQ+dYqk Sphagnum moss

Correct. The kelp and Sphagnum moss are photosynthetic.
Incorrect. The kelp and Sphagnum moss are photosynthetic.

Question 1.25

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Question 1.26

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So far, all of the photosynthetic organisms we’ve studied in this lab have been green because of their light-absorbing chlorophyll. However, not all green organisms are photosynthetic! Consider the lizard below:

Question 1.27

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Correct. It is a consumer that must eat other organisms for energy.
Incorrect. It is a consumer that must eat other organisms for energy.

Question 1.28

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Correct. Its green color is an evolutionary adaptation that allowed it to survive.
Incorrect. Its green color is an evolutionary adaptation that allowed it to survive.

Question 1.29

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Now that we have determined the organism with the highest rate of photosynthesis to use for our biological air filter—green algae—we can proceed to the next part of our experiment. In the next section of the lab, we will determine the perfect habitat to make our algae bio-air filter function at peak efficiency!

Section 1.3.2 Requirements for Photosynthesis

We’ll be testing a variety of different environmental conditions to determine what is best for our biological air filters. The five conditions we’ll be testing are: the levels of CO2, oxygen (O2), humidity, amount of sugars supplied to the algae, and different colors of light.

Question 1.30

Based on the chemicals required for and produced by photosynthesis (which we covered in the background information), which conditions do you think will affect the rate of photosynthesis in our algae air filters? Select ALL the conditions that will have an effect.

bI0LPa9lfHQ+dYqk Carbon Dioxide (CO2) level

wCfH0QtRgXJ8o+c+ Oxygen (O2) level

bI0LPa9lfHQ+dYqk Humidity (water (H2O) level)

wCfH0QtRgXJ8o+c+ Sugar level

bI0LPa9lfHQ+dYqk Color of light

Correct. Carbon dioxide and humidity levels as well as the color of light will affect the rate of photosynthesis in our algae air filter.
Incorrect. Carbon dioxide and humidity levels as well as the color of light will affect the rate of photosynthesis in our algae air filter.

Use what you answered above to predict the effects of each of the environmental conditions we are about to test.

Question 1.31

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Okay. We'll see if your prediction is correct soon.
Okay. We'll see if your prediction is correct soon.

Question 1.32

TfCnOsnPdufGUJlsHib+5CSHPQWo6hayWri58dHdJW3RxaHzWqaIMcBc/dIWR/yU

Question 1.33

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Okay. We'll see if your prediction is correct soon.
Okay. We'll see if your prediction is correct soon.

Question 1.34

TfCnOsnPdufGUJlsHib+5CSHPQWo6hayWri58dHdJW3RxaHzWqaIMcBc/dIWR/yU

Question 1.35

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Okay. We'll see if your prediction is correct soon.
Okay. We'll see if your prediction is correct soon.

Question 1.36

TfCnOsnPdufGUJlsHib+5CSHPQWo6hayWri58dHdJW3RxaHzWqaIMcBc/dIWR/yU

Question 1.37

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Okay. We'll see if your prediction is correct soon.
Okay. We'll see if your prediction is correct soon.

Question 1.38

TfCnOsnPdufGUJlsHib+5CSHPQWo6hayWri58dHdJW3RxaHzWqaIMcBc/dIWR/yU

Question 1.39

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Okay. We'll see if your prediction is correct soon.
Okay. We'll see if your prediction is correct soon.

Question 1.40

TfCnOsnPdufGUJlsHib+5CSHPQWo6hayWri58dHdJW3RxaHzWqaIMcBc/dIWR/yU

Before we begin, we must make our algae biological air filters. The algae in this pond scum will work wonderfully, but we can’t just throw pond scum everywhere. Instead, we’ll grow pure algae on vertical membranes. This will be cleaner and much more portable; we can bring these algae air filters wherever they are needed, whether that’s to the moon or down to the depths of the ocean.

To make a pure algae air filter in the lab, you'll use a pipette to transfer a couple of drops of pond scum onto each of the filter membranes provided. First, click on the pipettes to pick one up, then click on the pond scum sample to collect some of the algae. Next, click EACH of the filters to add just a couple of drops of algae cells to the membrane. Just a few drops will be enough— we’ll wait a week to allow the algae to grow and cover the entire membrane. Once you’ve added the algae to each membrane, click the “Wait for Algae to Grow” button to allow time for the algae to grow over the entire surface of the membrane.

Once you have some bio-filters prepared, we can determine what the ideal conditions are to get them to photosynthesize as much as possible. For each of the conditions, we will test three different levels. First, you'll select one of the five environmental conditions to test. We’ll examine each of these independently to make sure the results are not influencing each other. Once you’ve selected an environment to test, you will click-and-drag an algae bio-filter to each of the three CO2 chambers. You’ll use the pond scum you’ve collected to keep making more of these, so don’t worry about running out. Lastly, you'll use the controls on top of the CO2 chamber to set the three different levels we’ll test for this condition. Make sure each chamber is set up differently! Once all three steps are done, you are ready to run the experiment and begin collecting data!

Question 1.41

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Correct. We are testing the rate of photosynthesis in each environment.
Incorrect. We are testing the rate of photosynthesis in each environment.

In the previous experiment, we were trying to determine if photosynthesis occurred or not, so it was enough to simply see if the CO2 levels in the chamber increased or decreased. Now we know photosynthesis is occurring, but we want to determine when it is occurring the fastest, so we’ll have to get a little more detailed in our experiment. We will run each experiment for five hours. After each hour, you will record the level of carbon dioxide gas in each of the CO2 chambers. This will give us some data we can graph and compare to determine the best environment for maximum photosynthesis efficiency.

The table below shows the hypotheses you made before you started this experiment. In the far right column, select the actual results we saw in our experiments.

Question 1.42

Environment Hypothesis Actual Result
Increased CO2 level (Insert question #33 response) Photosynthesis hW2d51pWQ5Kx3e1loDtCmt+aQjANeE7GxNaeej/rJ2Xb7ZSrN/2HIQ==
Increased O2 level (Insert question #35 response) Photosynthesis /NfNQuvdiR81a1rMbUJtxZxJ8QDz7OlMqgJi0m12CwsxKAbmutzwNw==
Worst Color of Light (Insert question #41 response) RflGwQQXGXa8k506Tg1jo7LcnRghikzP4dS4ZCxsGeEzIiLP
Increased Water Level (Insert question #37 response) Photosynthesis hW2d51pWQ5Kx3e1loDtCmt+aQjANeE7GxNaeej/rJ2Xb7ZSrN/2HIQ==
Increased Sugar Level (Insert question #39 response) Photosynthesis /NfNQuvdiR81a1rMbUJtxZxJ8QDz7OlMqgJi0m12CwsxKAbmutzwNw==
Correct. Increased carbon dioxide and water levels increased the amount of photosynthesis, while increasing sugar and oxygen levels had no effect. The worst color of light for photosynthesis was green light.
Incorrect. Increased carbon dioxide and water levels increased the amount of photosynthesis, while increasing sugar and oxygen levels had no effect. The worst color of light for photosynthesis was green light.

Question 1.43

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Question 1.44

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Excellent, we now know the best environment to get the highest amount of functionality out of our biological air filter. I’m sure NASA will be excited to hear your results. Meanwhile, there are just a couple more experiments you need to do to make sure you understand and can explain how this biological air filter works. Next we will examine how it performs at the cellular levels.

Section 1.3.3 Photosynthesis Inside the Cell

The algae filter is almost ready to go into production, but the sales staff want some visual aids so they can explain to the NASA astronauts exactly how it works. You’ve been recruited as a science advisor to help the animators create a visual animation that explains the process of photosynthesis—what chemical reactions occur and exactly how it filters out the carbon dioxide.

In the lab, the artists are going to ask you a series of questions about the steps and stages of photosynthesis. As you answer the questions, they will use that information to create animations of the process. If your answers are correct, the entire process should connect together in one sequence.

In a moment, you will go to the lab and answer all of the questions. Sometimes a question may require you to click and drag labels or reactions to the appropriate area inside the cellular organelle. Notice that not all the labels or reactions will be used: the animators may have made a few extra just for fun, so don’t let that trip you up. If at any point you think you have made a mistake, you can click the “reset animation” button to begin again from the very beginning.

Once your animation is correct, we’ll review it for accuracy. If there are any problems, they will be pointed out to you, but you’ll have to reset the animation to correct them. Keep trying until you have correctly constructed an animation that accurately depicts the process of photosynthesis. Then, return here to answer some follow up questions, demonstrating your knowledge of photosynthesis.

Now that you’ve successfully completed your animation, answer the following questions about photosynthesis.

Question 1.45

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Correct. The chloroplasts are the site of photosynthesis in plant cells.
No. The chloroplasts are the site of photosynthesis in plant cells.

Question 1.46

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Correct. The light energy absorbed by chlorophyll is used to energize electrons.
Incorrect. The light energy absorbed by chlorophyll is used to energize electrons.

Question 1.47

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Correct. Oxygen is produced as a by-product by the light reactions of photosynthesis.
Incorrect. Oxygen is produced as a by-product by the light reactions of photosynthesis.

Question 1.48

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Question 1.49

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Correct. Carbon dioxide is used during the Calvin cycle in photosynthesis.
Sorry. Carbon dioxide is used during the Calvin cycle in photosynthesis.

Question 1.50

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Question 1.51

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Your animation should really help our clients understand how these air filters work. Your results demonstrate that this type of algae can remove carbon dioxide from the environment very effectively. Soon it will be ready to carry out these same chemical reactions in an enclosed environment.

Section 1.3.4 Photosynthesis for Food

NASA has made a special request for you to test. They love your results so far—it looks like these bio-filters will be a good way to help remove excess CO2 from the international space station. However, they are a little cramped for space up there, and if these filters could do two jobs that would be even better.

Question 1.52

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Correct. Production of food is a benefit of photosynthesis.
Incorrect. Production of food is a benefit of photosynthesis.

The algae are producers: they can use photosynthesis to produce enough food to be self-sufficient. We, on the other hand, are consumers: we get our energy from eating producers. NASA wants to know if this algae can produce enough food to feed some of the astronauts as it filters the CO2 out of the air. It’s possible, but we’ll have to run some experiments to see if the idea will actually work. Luckily, the type of algae we’re growing on our bio-filters is actually eaten in a few countries. The scientific name is Cladophora, but some diners know it as “River weed” or “Mekong weed.”

Photosynthesis produces high energy sugar in part because of the First Law of Thermodynamics, which says:

Energy can be changed from one form to another, but it cannot be created or destroyed.

Question 1.53

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Correct. Light energy is the source of energy for photosynthesis.
Incorrect. Light energy is the source of energy for photosynthesis.

Almost ALL of the energy on the earth comes from the sun! It is captured by producers and converted into forms that other organisms (such as us consumers) can use. So, life on Earth is made possible by the first law of thermodynamics. Even the electrical energy that powers your home probably came from the sun—plants millions of years ago absorbed it through photosynthesis. When these plants died, they decayed and were compacted over LONG periods of time, forming coal or oil. When these fossil fuels are burned, the energy originally stored in the plants is converted into electrical energy.

When we eat food, our bodies also obey the first law of thermodynamics: they convert the chemical energy in the food into the kinetic energy of moving, thinking, living, etc.

However, this transfer of energy is not perfect. For example, plants only successfully store about 1% of the light energy they absorb. Not all of this stored energy is available to consumers, either. Some of the energy will be used by the plant itself, and some of it will be lost as heat energy. This is because of the Second Law of Thermodynamics, which states that:

The disorder or randomness of the universe is always increasing.

In this case, the heat energy given off by the transfer increases the randomness of the whole universe.

On average, only about 10% of energy that the producers transform via photosynthesis is stored. It is only this stored energy that can be passed on to any consumers that eat the plant. The energy in food is measured in “Calories.” The technical definition of a Calorie is the energy required to raise the temperature of 1 Kg of water 1oC. The average human being uses 1800 – 2500 Calories every day (depending on their age, weight, gender, and activity level).

Let’s look at a more concrete example:

Question 1.54

K4kAZdkYcnrr5w6/wwl0/VwjHILfs7B0C+fOe5iuYnvIe/AeTdSJElp6+e82dTuux+DJPIc9U7iuVaJxvEUq1gM+NtUAj8Zfnt89MtRaVmj7uUAQB2/+ZiUn5BCfF3hGLJvOYNkzCm5HB53Ha9kc+B9XuHj5z6N3ncOnbwMnaTQWa/CAoyIltV3zXJ+KRDhj2Opc6mJ/cQRU7AY8k/Ipoyp32YQe67zHA7NQBnRr/MGE/UwdE9OfplPkEhfpxfuFCtI5abojA45hzVOvwc0isvrAB343frViCo9dKiHagUGQnghg74LdOzkHeMLtRrpl
Correct. Only 1%, or 1 Calorie, is transformed.
Incorrect. Only 1%, or 1 Calorie, is transformed.

Question 1.55

nal4QrZzrqn2+h9aMowAU43W9ziLNFHJBUvvnLIJ4+8klSMXkHCkBwqbUMIe8t0FMALmZ2dgmb0f3rEFnH96KwxGC2gW36CucT6VawLAQaeR5fDM8qRpj6gT4G3XiQO4pFMDHSp0bwY3IfiHlRP6rLLIMBRzwFLeyaC3fgdYnqn7RjCQyRfHpCxgNOtPz1mLiIW0EXNe7ekgGNhF
Correct. Plants transform the energy they absorb into chemical energy.
Incorrect. Plants transform the energy they absorb into chemical energy.

Question 1.56

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
Correct. You could expect to get 10% of 1 Calorie, or 0.1 Calories.
Incorrect. You could expect to get 10% of 1 Calorie, or 0.1 Calories.

Question 1.57

4PG8gmMRzh262l67OzSxUjQNhyw6mjtrD0YyKkHMMtvPO025tJjP03w+zZ4Q9ZY/8ptWotEi/l7yinsNdAN8Cg9mmn2S6OoyZLXihehtEgmuJdrR7hLhLrX2JLuOzxMeqWs6iaOTwInIEJLbAxrICQQtAz0tWFcPssQOSsHHVfJDSV8vn3yiRdqXr9PR8SKWSUu42JiXs+i/cqLUJ172F8I0qi+TjNQJQ1Lj55uCfNXOBLQO0BnBfP37fWmGvwPx6jTPq0Mf958LsPwyYKW17Q==
Right. The correct energy path is light → algae → human.
No. The correct energy path is light → algae → human.

This means the question really is: Can we provide enough light energy to our algae to make it possible for the humans who eat it to get enough energy to live? Obviously, we can’t test this by starving real people, so you’ll run a simulation on the computer in the laboratory. In this simulation, you’ll be able to test the outcomes of providing different light levels to the biological air filters. Examine the outcomes of all the different possible light levels. Make sure to notice how much energy is transferred to the algae in the bio-filter, and how much energy could potentially be transferred to the humans who eat the algae.

To access the simulation, click the computer sitting on the lab bench, then Click the “Run Energy Conversion Simulation” button.

Congratulations, that’s the last experiment to test this new type of bio-filter. These results will be passed on to NASA and they’ll make the final determination whether this algae-based system will be a useful system for their spacecraft. Who knows—your invention here may someday help us walk on Mars, or beyond!

1.4 Lab Report

Question 1.58

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
Correct. The purpose of this lab was to design a bio-filter that could remove CO2 from air.
Incorrect. The purpose of this lab was to design a bio-filter that could remove CO2 from air.

Question 1.59

Introduction:

Complete this partially written paragraph by choosing the correct words from the drop-down menus.

In this lab, we needed to set up a system that would EedFGZKjom/8cTb5iqxEgSvfwQz8KQD9VMDnp5TqMnD9+7unHVAi2wrWaJp0LnJ7Cd3mdgaF85v4w6Itj1m2MGHJ7h7PRRN23dHhDg==. During the process of XfdKmVXED7JkeD8H0raWrBApuvqKNY1lU2AOFPhqI09kSNPr4qywk1j36SwPh/PG3q2hazfEffM=, producers take in and use B8T3ntt4IuQ+klSqh0tS89rjZEQaImx93R8ZFw== and /Gsw7zNrJJf5rd+yuFXc9w== to produce 2X3oW7tmWK4GcOG6S1I4fZtefC/PtYeozigo5DOlkvE= and qtASKMFYdfUCXvlGjuSrysQtztbJtOY2RJ5iE0MXB3cgHYW4CXeTnqXH7KM=. The first step was to L8KkXX2QK86u9MAs2cIZlgb9SxUq8uYAc1+Q5MsUIj5Skoy891LI2bTrukA2r4ZJeWk1ePs6/nU=. Then we tested different variables to determine +Eq+Hidu4wHWugC60cXtTfw0Fmzi2IlVJB0yKHSrGpBEyN7mh23pujEuSx8uRj/qgrzHcDnixJC5Hvzr2RoknkSncG6904cqFrV8egrE7fs7gEFg7oieXQma+v0= for the creation of our filter. Next, we used e6GnRffPPfBRa1ZoPt1jDm4PfsKKHg46YAIEaIU40lvrMC9YlHL9HozlRO4= chemicals to observe the process of photosynthesis within the cells of the organism. Finally, we simulated the nX4B5Jd7vqyeIkOvB4M9jXFi3lgYFHJ7Ts0IBb/DoJmiIqMNqCVWwVt+onBJL2lBtzp9ELKI5h9P+lI1yMybwvvKS5I= to determine if the bio-filter could provide NdZZdaLg1hy/6xPIzRVxItjtp8oXm5cApdXNhUj2dQqfcQMb for humans.

Correct. Good job!
Incorrect. We were attempting to create an air filter that would allow humans to breathe in confined situations where there is little or no natural, breathable air. We chose an organism, determined which environmental conditions were best for our filter, then used radioactive chemicals to observe photosynthesis within the chosen organism's cells.

Question 1.60

Materials:

From the following list, select ONLY the tools and materials that were used in these experiments. Select ALL that apply.

bI0LPa9lfHQ+dYqk Environmental samples

bI0LPa9lfHQ+dYqk CO2 chamber

wCfH0QtRgXJ8o+c+ spectrophotometer

bI0LPa9lfHQ+dYqk Microscope with video screen

bI0LPa9lfHQ+dYqk Filter membranes

wCfH0QtRgXJ8o+c+ Nitrous oxide

bI0LPa9lfHQ+dYqk Oxygen

bI0LPa9lfHQ+dYqk Lights

bI0LPa9lfHQ+dYqk Water

wCfH0QtRgXJ8o+c+ Dry ice

bI0LPa9lfHQ+dYqk Sugar

wCfH0QtRgXJ8o+c+ Starch

bI0LPa9lfHQ+dYqk Radioactive O2, CO2, and H2O

bI0LPa9lfHQ+dYqk Energy conversion simulator

Correct. We used the following tools and materials: Environmental samples, CO2 chamber, microscope with video screen, filter membranes, oxygen, lights, water, sugar, radioactive O2, CO2, and H2O, energy conversion simulator.
Incorrect. We used the following tools and materials: Environmental samples, CO2 chamber, microscope with video screen, filter membranes, oxygen, lights, water, sugar, radioactive O2, CO2, and H2O, energy conversion simulator.

Question 1.61

Methods:

Put the steps from our four experiments in the correct order.

Experiment 1

Step 1:

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Step 2:

EzCkFFKH3aerSL2SuOeXHCoggBCIk7qMNFUCyvhIjqLq1m0xEYNoJFZ1A/pDbvjs8SffaoofLIMeIsrWcdvsIOLwKp9IdTw130kXGbqEnGyW91489iiklVTs2zwd+zcmpsUj1Z8hTgqKGlcMSdFyh23ora+clVSu5wB0QxfsDzUHUzw/ejrQFTOdMQHj+FrompasiqvJw5uAXTOvS4J9rTcCLkGshwIafbeRdeuCP21M4vC6WvIIxaCUB/D47JbaDoHRi9EuudGzrqkjGbn4DLjRXOeR5HVOXuT2et38qY6C+wx0zgiCuQ==

Step 3:

lwOt8B36aQU1icRdDl3ShXkFH4duvXVK/iQ01NveLVuVOekAiRGALizD9V10/ZqbAbFGIXg3/szq2tCnPVM3fOPcbOYaWGRS3rxQEpjNKUwlIKmBdFhyRaaiKk/tr24ij1w1lWCvTFLTJz3Heh0C8vaGwHJQL7bQyOZkEQRnlJ2qCs9d9nrpVjq4Y6AUXgw4MNIm5o10oyaTFMNHpm3f7e1IaQvipsCpqV9x2paJA3NqZ3qN1ItK2ZVDs7jNPNRjjx+AZuq0t22RQceZFTp64hD7mn9tRi7D0EINKe3C7T6U22vcKmTjtQ==

Step 4:

rE1CMMBkFok8KWLuW03swVou+CkQw3at36jMTVALcpnaMfqZcOO+GR4BTw/T4Tv7A+7V+CivzwkZ0ISKNur5DUWhOyihuiH1xiJvOb8ABKRurElgrsWLiL6SS+OmL2IqwBd8tHfRnOfD0bQahKZOpgRU0FLHiyAfisPLbAH2M9K2UxyHwIdsVOGOAbO4QTcOFA3Q6YwWRs+j2a+n5yeuyAjqgqpdm60A8GdwXRd7iFVjL//KFvOUcFTgIt/7CEslH/au3v4uGFrdyloCMv61Z/9vN5+9LDMXRbln7Mhdcb9SlHwXykKN5A==

____________________________

Experiment 2

Step 1:

kjEfYPeYAYAwbvSsgcdkPAUpq18eoOb7uGW5ym3G/ALSEj5uWjUcEWl7Jvtw+HESLAjeFm0ktx/vHABLBTSjWJKF9OVQo5srSOF52a42K6nm2/4dTalXD8eDHvCsc69cxLVbQJN1M7MTDQjhJ5YE5bhWCI3t3g+LrQqrki5AaNtSsbeNvwkBTOVAmwuvg9cvSIK63IQ6a0xw1bnxPeV2rF/z3Il7W1lP0mpTQkCiHX9O9NwlOCQHZgKSLVm8j2FzzuG1tigPqIVmGh/zI5uYBVb3b7tjxLrKGmUarhu/dHu+/grF+gne1JI8pKk0CP8nqOpvhdFLiHFYGAMgcRAuIf0MAX5p/RFnA+BgbesMwOn0+ntUnn6Hv5y09mzLQ+01u8nEqBZlPgCink9h

Step 2:

kFi6OhjGVOTwVHDSi1KL+Rakeo+XWTvzlyt5oXSsferEKbJiYkTic9pI2h3cbqz1FmKJISP4yHv59n5c7lJSaobnBBAyADR7jTutvZaWkXJAgXghq8KDzr4c5r+MXaKRMb4q5/Lc+m2+ns8Ar7tLZsDaKQciBMy6sbVWQX6XLrhn/OQtRkzPLANQZejOrQr5o0/+JD9Y1pFxXnVaUeVUYFvWTxP3zQZfH5MOPiyb1NIU895Q2++lsnjvUO8hlgUJgDXtFgps4/ZJHn7TL0bIiUS7lT4i/DW6p1OnKLB4NVf11USE5sZYaMKVyfDzSBU57pbuhwPhjogM3y/vZ0E7zXB5+GV6L5IPzU99VywiiXTSwyOBChXF+qTObrc4cjBc74ucdqJlI9xQMP/h

Step 3:

IXT76WBU8PhhWTxYuNahAlxJ5/vidR/bS2UIrf0pQbXCYifiK5ctRjN4/Gjlnxm3Ww+DTHlOmKhFzTPRZJT4eow1hz84JJYXprX/Cg1uFxudqkOPQtdmY9iq/oq3d5wyWroUepZiRnCRA6f3U+SRrq6jxwH2diHw+7HTXmp3c0uPsCC7319nsjxS+6TXSxmKqhSSMHe4W6pxkVtE515cYY6RXn+c8ZwPHL3cSZyZ7Sfvesm9RXfx/72izXGYnky/Otv7Wh/t3nIc6kY1BA4FHJHxw6W9dZYKdM6Czlxtb8CnWAD6FyICjgR3JZ1aPe52TImassbH0lYk+Y2XXcoI5/n/K9lWBvL1Vred6VRXE5wrZrWExPS6UiLjI5HwOds4GKJxKYte415Kfqhe

Step 4:

gW2VZih+qHzPmB4nJFUnyHT7FB0YtI6ppEBWPt7bp1upYfHzU8QyypbTl7WT+WNJLEUYfXwDwMJw7SjE/Mm/QsdGEqCrko1M8A3znDr2lZhTIZvRLZ53OIwubzls9r2x2SqPytp13g1dp4Znoy3M+U4e6f87qNYk1mHiIZzepQgwCydlkXIIzgtbQLPCG67UUgr0B80WljDFYrQ3Wr63yD1OTwMX+vy+AmZ7BDNPUPJ6Pww+7IB5sW8NtV07AlUBrKxrby3sPjfvjpDlY3D4JeUj0mtYvz9Hy9/d2vKxA5RUq0ObW6imCMsCvnbWl0438CW8shQn9jlQTM/CNoWxmlLiAeEyUvbsgpCEWWIkY/DujqpcL+GUoVbD8oTfvHvavFV3SZi1dhMlQpvB

____________________________

Experiment 3

Step 1:

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Step 2:

oYanYVL8rWrm92SVsEJ92OhxqoznckvkhexWxWkesRYzsqy2ZuxGhZSuPPxIkWa8Qys33kOUWl3WWSrMBpbDUmzcUU3Gx8FFcZwYB6qT1w1p0rZ1aiWV/atmVkxV7oRJcCejDqwR+PwKIsES22wUpNgvnmhZGdgBRip6o+EbJaSR8ak4AV28VlxvWe5zfANcJ/+QtGBYYusP6rhqfnxMfVTJwws9cwXKMDw2pIu43gwv1fgOIOP1NA==

Step 3:

puYQiM5NzAKsG8BjZRO0THVEF8oFr6wnlidwsVRequSEwc0uewFtb3a+8LxgnABgWtauNtFLwitI2Rz9BR8X+dI/Pw+JSwwGNGyqwRmWod/Ks4XkFzsfifhpCXAkLx/qTpBCjvg3lkSgjqi0SBqtTZUaecx/FYoUKnLK+GVX17yXW8oaIWfRV4V6RonntYxoL/E+BJ0/n05YrN0pPf0cvM+xFRFWO92jhCW7dC+cK4IqBJSYFN6yzA==

____________________________

Experiment 4

Step 1:

fjKixObnpStp4N/RYWanbpLQ6dnrOoK1R/IWWknAA+1nOgeKYEjNjI9v0eQHs0p9+SbZcZ+LCLajmEFkYF1AlhfaF2KhqQlFINbZmduFFwG69wn8tb4QnQaFLYjNGSZiiHgO8mn+s96xYEjflXYVNqsBLex7m0VR7JgypgJ/+I4mFNghMkpmPBLuVa9Or6EJ/oI95Pj/PxNYtQCmBtQ6M6YqvR88kyvn5wp2Axqbh5FK36zmhZSDM9LLJiHAgdTBx8YseA==

Step 2:

K85e0E4pE3vS0YNNVnZjOgWihdSxwoWQgqURUEPlSJHN3af0krelj7NG7v8cCqfprpPpfE0dLIf+hKIe2smvNq5cGd0Gu3lF9uakGF+3FNNidjxTucPT1bmtEQm+LqmsqMYOMUZfvweTqymZduxqoLVPUb2Z3lcDJ2Ymr13VHlXSXuMZrKBw4YilBqBJo7gVz1q9NCkxkLXMiTEsBpVw51Uh82UrElacu/Lh9e1i/LRXi4irP16qEBs7t0m00BHQY1vs0A==

Step 3:

0MX+PNGXfpeiJX4d+2aq7XAm2CrPqnXNqCV2iC94iEDC5AHTjStbZ4nnOecBG1GqqEyK8sj3+wk9I3Ex0ODZSAKSdD4a3SDhExc8/NsQtgh+Fc04XoFDEOgL2XgN9i1YqiV4tU/fNW8Wh2aVx8tIPM6rEG7P9DWoRIy/Zvq8nwL61bV9kG5J9l26hG9Xjf/GgN8X6LdDf8GlDfELc/63NOPKWIA4syHH3G/SBIrnIHiwWrzAwonp7G5LOfN9oFwR7mKrIA==

Correct. Good job!
Not quite. Review your incorrect answers.

Question 1.62

Results and Discussion:

To complete this section of the lab report, you will have to fill in the blanks in these sentences. For some, you can choose the correct response from the drop-down menus. For others, you must type in the correct response.

In the first experiment, several organisms were collected and then studied. The rate of photosynthesis in an organism was determined by the rate at which qRFPcFgthGZGFWlSzKnblZzCf2Zkk/dt4EsLPpN+l07FYctydgr5hw== levels 0McMpYX55alz+G6FBKBEQ7b8GDN5DLBu in the CO2 chamber. Based on these results, it was determined that two organisms were not photosynthetic—the duck and the ihC0+LNuraQ=—so they were not studied further. When the pond water was examined under the microscope, it was determined that the photosynthetic organisms it contained were Euglena and kVEpL3UAZMQpi6tJ5UIBRR+BbASKyQZyJAVEGA==. The fact that these organisms were piqdi0XdTgDaYDurpE1em0WR84RFLWeQ confirmed this result, because it indicates that they contain lRX9z5raIflDWaSM+vuiKANdnDdduI9qrgVXZgb9M5U6FQS8CJL5Bw==. The fastest rate of photosynthesis was seen in the tVuSGOMwJ1jBz8kcJ/NlHaOBVrnowO3XDnmKfwd8RjxNUuhpTMcz8sUMn1+rVMaK. As a result, the organisms chosen for the bio-filter were h2POMPFTo+R3bEjU8YfCp4UzhsuPZhkMQO70aZPkDXM=.

In the next experiment, different environmental conditions were tested to determine what conditions are best for photosynthesis. Increasing the concentration of oxygen Keb7IlDPEzx1DEwzSWh+Ug9jBM3emovWirFFlTLHv5/f2Pa2B4UMsA== the rate of photosynthesis. However, increasing the concentration of carbon dioxide rBJ8Bg4ggdPlHDrGuSUgRY3JwpdbkUxqr58TmVS6NL8HIpc1UfODfA== the rate of photosynthesis. The concentration of water rBJ8Bg4ggdPlHDrGuSUgRY3JwpdbkUxqr58TmVS6NL8HIpc1UfODfA== the rate of photosynthesis, while the concentration of sugar Keb7IlDPEzx1DEwzSWh+Ug9jBM3emovWirFFlTLHv5/f2Pa2B4UMsA== the rate of photosynthesis. Of the three wavelengths of light tested, the least effective was 1fYhGdRSJOvyd2z9SaVAxKKsNeY= light. So the optimum conditions for photosynthesis would include high levels of carbon dioxide and M2tGCdSKIQcdWsJTBI+pLUO73GXtGCmZRtTJptg/ZeOyQERI4+P0eQ== and either red or YLgMaD3jOvzy8Mv7FJa0Xe/NX38= light.

In the third experiment, algae cells were observed under the microscope while radioactive chemicals moved through them. This experiment had to be conducted with the lights (on, off) so that photosynthesis could proceed. The radioactive oxygen 9YVB8givZyZKfkzMiiuPMCwgfUZwseghwEH0MAAeIImefdgV7FLsDUXX1wPXoUK0CVSfMR++wl0DsvSCAjGuzwdEHPtoC3q1k6gn6qVkEdrk3TQNIWQH1g==, which indicates that oxygen I3+WRtmdgg+BxWMPIH9V1w== used during photosynthesis. The radioactive carbon dioxide iS29jebifEPdFpj0jkH8/D7C9cxG4t2+SSKPHozYLeWwHSc01Rf6QoqvPswOJHTiN60qnfmCMYZIQQVtsNGcuQ== because the cell 44oTTldiImgiDH5SKtUXvfYKWw2jaTjr4ScqAQ== during photosynthesis. Eventually, this carbon dioxide will be converted into pF0YbQ304749o7PXXJzfCPyJSKQpfCP0Y81k4cR7f0o= that the cell can use. And finally, the radioactive water molecule was split apart, and the 8F6MmnvwoGuiSWt+TRoIFLAt5Ms= it contained UXOCDS+5IQpR/Sf4JaVTF6pGnjZ42IiZWyXB9PsI5kfCaU2pU1IpGEMvcx4=. This byproduct of photosynthesis bfdtn5PFpMarVC8x2zfiEQ== used by other living organisms in the environment.

Because one of the products of photosynthesis is r7WMMYdI/otaDiYaT4AGhB8dId+fsLIXSeyaRqu8R2Y=, the final experiment tested whether the algae can produce n3a1YY/HE1RKTfD4kA5iAVG4xenEsFVyV5+s/w+KgII= for humans. It was determined that to meet the calorie needs of an average person about Wglm/T+Vdal+qgMnn0Z+7JB80hhHONpIfoTzL8rmItZK2N8z calories, the algae would need to transform 3WkyzBJY0LS/Ag4FY5JiCcK68XinhuoM2vhur70nYhDF8PBl calories of energy. For this amount of photosynthesis, the algae would need to get xKFUKWIDP61E/oWuOd5ThU0YwfYj+P1+o9yf25W/FP0= calories of energy from the light. When the light is set to this level gfRA3KC4QNj3rFwf7mRXM/g3JZK/1uh2B8oPKpZrggL+Mg3JU1CNVyXR5TqWgHZ+HvY8a2RR5xy2lQte7gFEMNxlShvxJTWlUsUFYY6YgLymjq7Kzg1u2puJq78=. The final conclusion is that this bio-filter fNwX5Bzl7sTGIM5j49ERNyLiD/w= be able to provide a food source for humans.

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1.5 Vocabulary List

Chlorophylls: the pigment molecules in plants that absorb sunlight energy.

Chloroplast: subcellular structure where photosynthesis takes place in algae and plants.

Carnivore: meat-eating animal.

Consumer: an organism that must eat other organisms for energy.

Cyanobacteria: group of photosynthetic bacteria that gave rise to the chloroplasts in algae and the plants.

Green algae: aquatic organisms found in both salt and fresh water. They may be single-celled or multicellular; they are photosynthetic.

Herbivore: animal that eats plants.

Photosynthesis: the process by which plants use sunlight as an energy source for creating sugars. Oxygen is a byproduct of this process.

Pigment: a colored molecule that can absorb certain wavelengths of light.

Plant: photosynthetic organism that is multicellular, may live in water or on land, and is more complex than algae.

Primary consumer: an animal that eats plants; a herbivore.

Producer: an organism that can make its own food by photosynthesis.

Secondary consumer: an animal that eats animals; a carnivore.