Advanced Biology Students See the Vegetable Everyone Loves to Hate in a New Light

The first weeks of school have been full of poignant teaching moments and hands-on experiments in Dean Mohlman’s Advanced Biology II class.

“I try to do things that have an “aha” moment [in class] because that’s memorable for the students, as well as having a substantial educational aspect,” said Mohlman.

On this particular class day, Mohlman wanted to create that aha moment extracting chlorophyll from spinach leaves. Rather than eating the leaves – something much appreciated – his 11th and 12th grade students placed the leaves in a mortar. Using a pestle, they ground up the spinach into smaller bits and pieces. They then added ethyl acetate – a chemical that breaks down the cell membrane and chloroplast to release the chlorophyll.

Placing the spinach under a glowing red fluorescent UV light, the students can see higher amounts of energy. They can also see that they’ve excited the electrons in the chlorophyll molecules. After boosting the electrons, the molecules return to their ground state, which then creates a fleshed out eerie reddish blue color under the light.
Mohlman times this particular lab early in the year because photosynthesis and how it generates food in the plants is one of the first things people typically think about in a study of living things.

“It all relates back to how chlorophyll is so important to every living thing,” said Mohlman.

Mohlman hopes his hands-on teaching makes a lasting and memorable impact on his students. He says he hopes his students remember and refer to these kinds of experiments as they dig deeper into the science of photosynthesis. 

What will Mohlman’s Advanced Biology II students be tackling next? They recently covered the unique properties of water and how those relate to living things. Another lab is on the horizon involving pH and exhaling carbon dioxide —  to illustrate how important the pH of our blood is, which leads right into their theme of homeostasis.
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