In order for a living organism to survive, it relies on energy. This energy must be stored to prolong its lifespan, otherwise, the energy is rendered useless. We all know that humans and animals store energy by consuming foods that are then turned into usable energy, but what about plants?
Plants store energy in the form of starch. Starch is a complex carbohydrate that is broken down by amylase into glucose in the human body. In plants, starch is broken into glucose by the process of photosynthesis. The glucose is then used by the plants as their main energy source.
Here is everything you need to know about the form of which plants store energy.
In which form do plants store energy?
Starch in plants works similarly to starch-based foods eaten by humans. When a human eats a starch-based complex carbohydrate like a sweet potato, the body will slowly digest the carbohydrate, making the person feel fuller for longer. Regular carbohydrates, however, are digested too quickly to be used for energy. The same goes for plants – the starch is essential for slowly breaking down into a digestible energy source.
Time to take you back to high school biology class! Photosynthesis is the process when a plant takes the energy from sunlight and generates it into energy. This is achieved by the surrounding water and carbon dioxide in the atmosphere, which is then converted into oxygen and glucose molecules. The oxygen is released into the air, while the glucose remains in the plant to be stored as starch, which then slowly releases the glucose as an energy source.
Interesting Fact: Too much water can kill the plant as the plant no longer has access to enough oxygen, which works hand-in-hand with the glucose that can be used for energy.
Glucose is a sugar that works as a food source for the plant, almost in the same way humans often consume sugar for a short-term energy supply. The glucose in a plant, however, provides a longer energy supply due to the constant exposure to water and carbon dioxide.
The glucose doesn’t just keep the plant alive – these sugars also promote the growth of the plant, flowers, potential fruits, and seeds. The seeds can then create a new plant, which then starts the cycle of photosynthesis again.
So, if a plant gets some glucose from photosynthesis, where does a plant get starch to make more glucose? The answer is that glucose is stored as starch, which then breaks down back into glucose again. In most plants, starch is stored in amyloplasts, which is a type of cell organelle. Amyloplasts are stored in the leaves of plants as the leaves have the most access to sunlight, which is then broken down into glucose molecules through handy photosynthesis.
The leaves, to put it simply, work as the storage container for the entire plant as they hold starch, which is then broken down into glucose (sugar).
How do plants store the glucose that they cannot use straight away?
So, if plants photosynthesize whenever there is sunlight, then where does all the excess glucose go if they cannot use it straight away? Good question!
Remember what we said earlier about the leaves acting as storage containers? All the starch immediately goes straight to the leaves as the leaves offer the largest surface area and have the most frequent access to sunlight. The glucose that was in the plant already is on a consistent conveyor belt of use, which means that as soon as some of the glucose has been used for energy, it is almost immediately replaced. What a convenient system!
Now, glucose does not have a use-by-date in plants, so if it cannot be used straight away, it does not go to waste. Instead, any excess glucose will be used for other purposes within the plant.
What do plants do with extra glucose?
Plants will utilize the extra glucose by allowing it to promote growth. This growth can be of the plant itself, but glucose also helps to grow flowers, fruits, and most importantly, seeds. The glucose remains stored in the seeds as starch, which is essential for the regrowth of the plant until it commits to photosynthesis itself.
Now, here’s where it gets interesting. Once broken into molecules, plants have the ability to turn the extra glucose into large molecules known as cellulose and starch. That’s right – the glucose molecules can be molded back into their original starch molecule.
The reason a plant will do this to extra glucose is because, sometimes, extra glucose is not needed just for the growth of flowers and fruits. The cellulose keeps the cell walls strong and healthy, which is essential for keeping the plant stiff and upright. The starch is then given to the seeds as a source of energy until the newly grown plants can photosynthesize.
Why is glucose not stored in plants?
Okay, so here’s where it gets a bit confusing. Plants store starch for their energy source, which is achieved by breaking down the starch into glucose. However, plants don’t store the glucose – they only store the starch.
The reason for this is that any stored glucose in the plant works to dissolve the cell sap. This, in turn, increases the osmotic pressure in the cell, which prevents water from traveling around the plant. The starch, however, does not do this.
To put it simply, the reason why glucose is not stored in plants is that glucose is purely used as an energy source. The glucose is taken from the starch stored in the leaves of the plant, which is a result of photosynthesis.
Final thoughts
So, there you have it.
Let’s finalize everything we have learned!
A plant will undergo photosynthesis, which is the process that takes in water and carbon dioxide to produce oxygen (which is released into the atmosphere) and glucose (the energy source of the plant). The glucose is stored in the form of starch, which is a complex carbohydrate that is slowly digested into glucose molecules to release a steady stream of energy. The starch is stored in the leaves of the plant as the leaves are exposed to the most sunlight. This energy source then contributes to the growth of the plant, flowering, fruits, and seeds.
