5 Ways to Make Pigment Extraction A More Approachable Topic

Akanksha Saxena

Introduction: Pigment Extraction

The process that plants and algae exploit to synthesize their food has always left mankind awestruck. Photosynthesis, what it’s scientifically termed, as the process that ensures the basic conversion of the sun’s light energy to chemical energy. In the absence of photoautotrophs, it’s impossible to imagine any life-sustaining on the Earth as they constitute the basic nutritional source at the lowest trophic levels of food chains and food webs. 

Now, students wonder what makes these photoautotrophs so special in the ecosystem?

Do they have a magical power that converts sunlight to assimilable chemical energy (food)?

Do they instead use a wand to direct all of the sun's photos toward the creation of food molecules?

The magic lies in the pigments of the photoautotrophs. Pigment molecules are a special type of chemical compound produced by living organisms. They absorb a specified wavelength of the visible spectrum and reflect another. While different organisms produce different types of pigment molecules, the ones produced by plants are exceptional in possessing the ability to harvest sunlight.

Studying plant and algae pigments can open doors to untapped possibilities that can change the way we use and perceive sunlight. While we think of it as a source of daylight and a source of Vitamin D, sunlight if utilized properly can be used to run cars and fleets of the future. 

The topic becomes challenging to teach for many educators and teachers as the abstract concept of pigments with no real-world applications bores the student. This is why we, at Labster have tried to deal with this problem objectively. We will list the 3 major problems faced by students while they are introduced to this topic. Special care can be taken for the same when you take the classes. We also list some practical solutions to resolve them. By the end, we’ll share why a virtual lab simulation will prove useful not only for your students but also for you as an educator to deliver concepts more efficiently.

 3 reasons why Pigment Extraction can be tricky to teach or learn

There are 3 major reasons why students are overwhelmed by the topic of Pigment Extraction. Acknowledging these issues is the first step toward making the topic more approachable. 

1. The topic is extensive and loaded with information

The topic of pigment extraction isn’t limited to its steps. Students are expected to know a lot of background information before hands-on training in this technique. The homework involved in the students’ part overwhelms them as the process of photosynthesis where plant pigments are involved in an ‘extensive’ one. Its content is heavy and loaded with peculiar details about plant cell structure, an endless list of plant pigments and specificities for the sunlight (different range of excitation spectra), location of different pigments in different parts of the chloroplast, uses and importance of photosynthesis process in the ecosystem, a range of solvents used to extract different pigments and so much more.

2. The utility of this technique is never told

Learning this technique becomes further monotonous as students can rarely see the direct application of this technique in any industry. Teachers educating students about this topic also have the challenge to enlist examples of the recent advancements in the field. This turns out demotivating for the students as they have to cram the steps for their exams.

3. Difficulty to follow textual explanations

Students have a hard time following the verbal explanations accompanied by the usage of limited textbook illustrations. So many students can’t even list the different wavelengths of light and their respective colors. The textual teaching protocols dull their overall learning. The multiple steps of techniques like centrifugation, spectrophotometry, cellular and sub-cellular fractionation, etc are very difficult to memorize when textual lessons are favored over interactive learning. 

5 ways to make Pigment Extraction a more approachable topic to understand

To address the issues encountered while teaching Pigment Extraction, educators can engage the under-listed solutions in their next classes. These can shed light on how to handle each issue that students encounter. They will not only make lessons clearer and simpler for your students to understand, but they will also make teaching easier for educators like you.

1. Make the see the utility

This is our foremost advice as it builds the interest of the students in the topic. You can quote the example of the utilization of algae in biofuel production. This field has been booming for the past 5-6 years and is expected to exponentially grow in the future. Only when plant biotechnologists realized that there’s no other machine as efficient as biological systems, they came up with the idea to harvest energy from plants or algae. Since the fundamental concept of energy in plants is linked to pigment molecules, their extraction and analysis gain prime importance.

You can use the Pigment Extraction simulation from Labster to engage your class in such an activity.

1. Make the fundamental concepts clearer

Another important suggestion for educators is to make the fundamental concepts crisp and clear. For this, you can prepare a list of topics related to pigment extraction and create stories around them. We provide a few examples of topics that can be made interesting with a little bit of effort.

2. Requirements of plants to conduct photosynthesis

There are 3 major requirements; sunlight, water and carbon dioxide. Now to relate the pigment molecules to each one of these components, you can build a story. How pigment and sunlight interact inside the plant cell’s chloroplast can be a good one, to begin with!

Make them see how beautifully pigments are arranged by nature in the chloroplasts. Since not all the pigments (chlorophyll-A, B, C, D, E, carotenoids, xanthophylls, etc) are located at the same position, explain how some are more important at a particular place than another. You can explain why carotenoids are such an important type of pigment and how they scavenge the radical species of oxygen (reactive oxygen species/ROS) and prevent any harm to the proteins significant for the photosynthesis process.

3. Fractionation of cellular components

The different components of the cell are of different sizes, shapes, and densities. When we are dealing with pigment extraction from a plant source, we majorly require chloroplasts. Now, explaining how subcellular fractions can be separated using differential and density gradient centrifugation is important.

Similarly, you can take more fundamental topics and explain them before the lab activity of pigment extraction.

3. Engage more interactive tools

The conventional methods of lecture delivery fail to deliver the rationale behind the techniques. They also make the technique seem boring and call for a load of memorization. Educators are advised to use more immersive ways of teaching where students can follow each step as they proceed. Flowcharts, animations, GIFs, short videos, simulations, etc can make them understand how the wet lab techniques are carried out. It can also help your students learn the basic precautions to be taken while handling expensive state-of-the-art facilities of research institutes. Visualizing the plant tissue extraction, chloroplast fraction isolation, centrifugation, solvent-dependent separation of pigments, spectrophotometric analysis to check the absorbance of different fractions, etc can make them interested n the topic and learn more about it.

To teach more about pigment extraction from algae, you can use one of the Labster simulations- Photosynthesis: Algae Pigment Analysis simulation. To teach how spectrophotometry works in pigment extraction, you can use Spectrophotometers: Building and exploring the instrument simulation and Spectrophotometry: Learn the Beer-Lambert law with absorbance experiments simulation


Figure:An interactive snippet from Pigment Extraction simulation by Labster showing the centrifugation step. The simulation is available for High School and University/College courses.

4. Build their interest in scientific planning of experiments

Rather than just teaching the different steps of pigment extraction, teach your students the importance of research aptitude in the scientific domain. Make them question the reasons and roles behind each step of extraction. Develop a habit of learning principles underlying the functioning of different lab equipment and instruments rather than the steps to operate them. Let them question why-

  1. Why balancing the centrifuge is important?
  2. Why is careful handling of the cuvette and keeping its side clear important before placing it in the spectrophotometer?
  3. Why do cell debris and nucleus separate before mitochondria and chloroplasts while ribosomes and microsomes separate afterward?

Explaining the importance of a scientific approach when they learn techniques and then building a scientific hypothesis to test a problem can take them a long way in the future. For explaining the importance of scientific methods, you can use The Scientific Method simulation from Labster.

wavelengths pigment extraction

Figure: An interactive snippet from Pigment Extraction simulation by Labster showing the differential absorption of different wavelengths of light by the hexane extract (containing plant pigments). The simulation is available for High School and University/College courses.

5. Use virtual lab simulations

Pigment extraction can be a very challenging concept to teach in conventional classroom setups. There are several reasons for it, the prime one being the dearth of interactive and engaging classroom tools like videos, animations, and simulations. To make your students see what happens at each step of pigment extraction at a microscopic level, we, at Labster, have a device for you. You can utilize Labster's Pigment Extraction simulation in your next class and see the difference for yourself. 

Your lecture delivery and lab management sessions will be made easier by Labster's virtual laboratory simulations. Because students have access to visual alternatives, you may make more insightful points. Students will be engaged with the help of our gamification components. Our virtual learning platform uses this method of interactive, immersive instruction to strengthen the fundamental concepts for future scientists in making.  

Get in touch to find out how you can start using virtual labs with your students.

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