Elodea canadensis, commonly known as “pondweed’ is a submergent, perennial aquatic plant native to North America. It is very invasive and is actually considered a weed due to its ability to grow in many diverse habitats and conditions (Podraza, 2010). Elodea canadensis is also sold as “oxygen weed’ to improve water quality. It is also known to show bubbles when it “breathes”, and this is key in its role in photosynthesis studies.
Photosynthesis is the process by which green plants and some other organisms use sunlight to synthesize foods from carbon dioxide and water.
In green plants, it involves the use of the pigment, chlorophyll b, and the generation of oxygen as a byproduct. When exposed to blue light (with a wavelength between 455-492nm), the production of oxygen in Elodea canadensis will be greater than when exposed to green light (550nm). This favourable blue light being absorbed by chlorophyll is what makes the plant appear green to the naked eye (as the opposing wavelength is transmitted and seen by the naked eye).
In accordance with the journal “Discovering Photosynthesis by Experiments” and the graphs shown in “Light Absorption for Photosynthesis”, it can be deduced that plants will undergo photosynthesis at much higher rates when exposed to wavelengths favourably absorbed by chlorophyll and at comparatively lower rates when exposed to wavelengths not favoured by chlorophyll. We can thus hypothesize that when experiments are conducted with Elodea canadensis exposed to blue and green light, exposure to blue light will undergo photosynthesis more efficiently and produce more oxygen while the one exposed to green light will produce less oxygen.
Saccharomyces cerevisiae (also baker’s yeast) is a species of yeast most commonly used for winemaking, baking and brewing. During what we know as cellular respiration, glucose molecules are broken down into carbon dioxide and water. Cellular respiration also transforms this glucose into ATP, which our body needs to perform certain functions. In the absence of oxygen, cells use either anaerobic respiration to generate ATP. This is also known as fermentation. In this process, glucose goes through two separate steps before being utilized for respiration, whereas sucrose undergoes one. As such, sucrose yields more ATP molecules at a faster rate than glucose. However according to research conducted by FEMS, although sucrose is almost always readily available for use, the main glucose repression pathway ensures that the preferred sugars are metabolized before the consumption of alternative carbohydrates. We can thus hypothesize that glucose will be preferred over sucrose because sucrose is a disaccharide that will need to be broken down further before used in the fermentation process.