AP Biology class blog for discussing current research in Biology

Tag: Globalwarming

Understanding a Plant’s Stomata to Counteract Affects of Climate Change?!

In mid January, 2023, researchers from the University of California San Diego made an important discovery surrounding photosynthesis, specifically the plants stomata, with climate change implications.

Tomato leaf stomate 1-color

Scientists have understood photosynthesis for many years. As we learned in AP Bio, photosynthesis is the process by which plants, algae, and some bacteria convert light energy from the sun into chemical energy in the form of glucose. The process of photosynthesis can be divided into two stages: the light dependent reactions, and the Calvin cycle.

The light-dependent reactions occur in the thylakoid membranes of chloroplasts and involve the conversion of light energy into chemical energy in the form of ATP and NADPH. During these reactions, water molecules are split  into hydrogen ions, electrons, and oxygen gas. The electrons move through a series of electron carriers and ultimately end up on NADP+ to form NADPH. At the same time, hydrogen ions are pumped from the stroma into the thylakoid lumen, creating a concentration gradient that drives the synthesis of ATP through a process called photophosphorylation.

The Calvin cycle, occurs in the stroma of chloroplasts and involve the conversion of carbon dioxide into glucose. During these reactions, carbon dioxide is fixed into organic molecules by the enzyme rubisco. The resulting molecules are then reduced by NADPH and ATP produced during the light-dependent reactions to form glucose. The Calvin cycle also requires a source of hydrogen ions, which are provided by the light-dependent reactions through the production of NADPH.

The researchers at the university of California San Diego, have furthered this understanding by explaining how the stomata is able to sense when to open and close in order to allow carbon dioxide and water to enter and exit the plant. When the stomata is open for carbon dioxide to enter, it exposes the plant to the outside world, and water from the plant is lost, which can end up drying out the plant.

This research is important because as carbon dioxide in the atmosphere increases, it could lead to the stomata of vital plants being left open too much, which would dehydrate the plant.

Fortunately, the research pointed to a specific protein, known as HT1, that was able to activate the enzyme that opens up the stomata in a low CO2 environment. The researchers also found a second protein that blocked the HT1 from keeping the stomata open in environments with higher CO2 concentrations. This second protein that was found is the reason plants will die when the atmosphere has too much CO2, as the stomata wouldn’t be open for long enough to get the necessary resources for photosynthesis.

This can relate to what we learn in AP Bio, in regards to enzymes and proteins. In AP bio, we learned that proteins are large molecules made of amino acids. Enzymes are a type of protein that catalyze chemical reactions. Enzymes also lower the activation energy needed for a reaction to occur. They interact with specific substrates to form enzyme-substrate complexes. The active site of an enzyme undergoes conformational changes, allowing for catalysis. Specific substrates can only bind to a particular enzyme. Enzyme activity can be affected by temperature, pH, and concentration. Enzymes work most effectively within a specific range of those things. Changes outside that range can affect structure and function. Enzymes and proteins play critical roles in many processes. Examples include DNA replication, protein synthesis, and metabolic pathways. Understanding enzyme-substrate interaction is crucial to understanding how the HT1 that activates the enzyme was able to speed up the reactions that caused the stomata to open up.

As Richard Cyr, the program director stated, “Determining how plants control their stomata under changing CO2 levels creates a different kind of opening — one to new avenues of research and possibilities for addressing societal challenges.” Hopefully this research can result in positive steps for the agricultural community as it takes on the challenge that is climate change.


How Baby Kangaroos Are Helping Climate Change

In the world, there are over 1 billion cows and calves, roughly 4.3 times as many cows as people living in the United States. Cows are the number one source of greenhouse gases worldwide, with a single cow producing 220 pounds of methane gas a year. Methane (CH4) is a colorless, odorless, and highly flammable gas, composed of carbon and hydrogen. Being a potent greenhouse gas, it impacts climate change by increasing global warming according to the US Environmental Protection Agency. Methane affects our environment but it can also impact humans “high levels of methane can reduce the amount of oxygen breathed from the air. This can result in mood changes, slurred speech, vision problems, memory loss, nausea, vomiting, facial flushing, and headache. In severe cases, there may be changes in breathing and heart rate, balance problems, numbness, and unconsciousness“. Although this is in extreme cases. Recently, scientists may have discovered a methane inhibitor that could reduce the amount of methane cows release. This source comes from an interesting source though: Baby kangaroo feces.


It's a cowspiracy ! - Wake up and smell the methane. (23335965671)


Researchers from Washington State University wanted to figure out a solution to lower methane gas production rates in cows seeing as people enjoy eating red meat and taking them entirely out of the equation is not a feasible answer. They performed a study using baby kangaroo fecal matter to develop a microbial culture that inhibited methane production in a cow’s stomach stimulator. This resulted in cows producing acetic acid – is also known as ethanoic acid, ethylic acid, vinegar acid, and methane carboxylic acid; it has the chemical formula of CH3COOH. Acetic acid is a byproduct of fermentation and gives vinegar its characteristic odor. Vinegar is about 4-6% acetic acid in water – in place of methane. Acetic acid is not just a waste product in a cow like methane but is actually beneficial for the cow as it helps muscle growth. Not only would lowering rates of methane production in cows be beneficial for the environment but also for the cow as the cow wastes around 10% of its energy in methane production. Researchers have tried chemical inhibitors but the methane-producing bacteria has become resistant each time. The actual experiment all began with the researcher’s study of fermentation and anaerobic processes, which lead to the creation of an artificial lumen designed to stimulate cow digestion. Then they began investigating how they could outcompete the methane-producing bacteria and learned that – specifically – baby kangaroos have acetic acid-producing bacteria instead of methane-producing bacteria. Researchers were “unable to separate out specific bacteria that might be producing the acetic acid, the researchers used a stable mixed culture developed from the feces of the baby kangaroo.” Eventually, the acetic acid bacteria was able to replace the methane-producing microbes for several months having similar growth rates. Researchers hope to eventually test their system outside of a stimulated rumen and on a real cow sometime in the future. This connects to our unit of enzymes and enzyme inhibitors. Enzymes allow the cell to perform tasks with less energy by binding to reactant molecules and holding them in a way that breaks the chemical bond allowing bond-forming processes to take place more easily. Enzyme inhibitors are molecules that bind to the active site – competitive inhibition – or the allosteric site – noncompetitive inhibition – making the enzyme unbindable, reducing the rate of enzyme-catalyzed reaction, or preventing it from happening altogether. This is what the researchers are trying to do in their study, inhibit the enzyme in the methane-producing bacteria and allow the acetic acid bacteria to grow instead. Overall, if this process proves to work in real cows it could be a huge advancement in the slowing down of climate change.





Artificial Photosynthesis

On January 25, 2023, Science Daily released an article about new research discovered by Osaka Metropolitan University regarding the Synthesis of fumaric acid by a new method of artificial photosynthesis, using sunlight to make biodegradable plastic. 

Global warming has caused a growing issue in our environment due to greenhouse gasses such as CO2. This research states that by using artificial photosynthesis CO2 can be reduced, hence limit global warming. This discovery shows that fumaric acid can be synthesized from CO2 and biomass-derived compounds using renewable solar energy.


As we have learned in Biology class, photosynthesis is an anabolic reaction because it builds up glucose, a bigger molecule, from water and carbon dioxide. Although –overall– photosynthesis is an anabolic reaction, catabolic reactions occur throughout photosynthesis because the large molecules, CO2 and H2o are broken down into their individual components- oxygen, carbon, and hydrogen- and then rearranged to create glucose using energy from the sun. In the Calvin Cycle, the goal is to produce G3P, from CO2, which will eventually become glucose, or sugar, however, this can’t be done without NADPH. 


Research discovered by Professor Yutaka Amao, stated that CO2 could be reduced by mimicking this process and can reduce CO2 by combining it with organic compounds. While fumaric acid is typically synthesized from petroleum to be used as a raw material for making biodegradable plastic, this research team was successful in synthesizing fumaric acid,  from CO2, powered by sunlight. This process is known as artificial photosynthesis. 

It is really interesting how mimicking the process of photosynthesis can lead to  CO2 being reduced when combined with organic compounds, and used as raw materials, which can be converted into sustainable structures such as plastic!

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