What is Photosynthesis?

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  • Written By: Michael Anissimov
  • Edited By: Bronwyn Harris
  • Last Modified Date: 03 October 2019
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Photosynthesis is a technique for converting sunlight into energy that has been utilized by certain organisms for around 3.4 billion years. The basic formula involves a conversion of carbon dioxide and water into glucose and oxygen, aided by light-dependent reactions. Photosynthesis emerged quickly after the emergence of life itself, thought to have occurred 3.5 billion years ago, after the Earth’s crust cooled. The first photosynthetic organisms were the ancestors of modern-day cyanobacteria.

Photosynthesis takes place inside chloroplasts, special organelles located in the cells of plants and other photosynthesizing organisms. Choloroplasts are green because they utilize the pigment chlorophyll. The primary sun-absorbing organs of plants are the leaves. Although chloroplasts are located in cells throughout a plant, chloroplast density is by far the highest on the leaves, where between 450,000 and 800,000 chloroplasts can be found in every square millimeter.

Chloroplasts are thought to derive from photosynthetic bacteria, with which they have much in common. Like the power plants of eukaryotic (complex) cells, mitochondria, chloroplasts are thought to derive from extremely close symbiotic relationships between early microbes, so close that they became part of the same inseparable entity.


One of the byproducts of photosynthesis is oxygen, the molecule we humans and other animals require to live. Although today oxygen brings life, during a cataclysmic event two billion years ago, it brought death. At that time, the Earth’s atmosphere contained little oxygen, and large iron rocks could be exposed to the surface without rusting. Then, during a geologically sudden period consisting of a few tens of millions of years, oxygen-producing photosynthetic cyanobacteria evolved and covered the Earth, producing massive amounts of oxygen and causing a mass extinction of evolutionary lineages unaccustomed to such high atmospheric oxygen concentrations. This is known as the oxygen catastrophe.

Today, the atmosphere is about 23% oxygen and the remainder nitrogen. The necessity of oxygen from plants is another reason why we should discourage the destruction of rainforests worldwide, particularly in the Amazon.

Photosynthetic organisms serve as the foundation of every ecosystem. In this role they are referred to as producers. Organisms which consume them are accordingly called consumers.


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Post 5

Thanks. I got information for my project.

Post 4

My favorite part about photosynthesis is the amount of time that it has been on this earth. If you think about it, the cells that create energy inside of a plant through the process of photosynthesis are like archaic engines creating food for the plant to grow.

This simple way of thinking about it will help some understand just what the power of photosynthesis is and how it can potential help humans as we come into the impending world-wide energy crisis.

I thin that as our oil reserves deplete we will look toward alternatives like photosynthesis as our answer to how we can provide the same energy requirements that our massive markets now demand.

To have a

set back in the forward moment of our industrialized world would mean a major decline in the standard of living for the average human as well as the most likely out break of energy wars between nations.

Honestly the situation has a potentially deadly consequence and we should invest money now into photosynthesis research as to avoid major issues in the near and far future.

Post 3

@thumbtack, while your statement seems very altruistic the unfortunate part is the logical fallacy that we could ever harvest photosynthesis for direct consumption of energy.

Basically because we our vehicles and turbines cannot consume glucose directly like a plant can, some sort of energy conversion must happen to harness the full potential of a plant's photosynthesis.

I have heard of rumors suggesting that algae could be cultured to expel gasses that would be combustible in an engine. If this technology were to ever come to the consumer market it would be one step closer to enjoying the natural benefits of photosynthesis.

Post 2

I hold out hope that someday science will be able to harvest the power of photosynthesis and create usable energy out of it. Imagine if we could use the output that plants create for our fuel and costly energy supplies.

Just like the author states, it is incredibly important for us to decrease the rate at which we are consuming plants as they provide the earth with energy and oxygen.

I guess in a way, solar panels are like artificial plant leaves except instead of glucose we are getting electricity directly out of the energy conversion. Either way if we are able to develop the technology that harnesses photosynthesis, there will need to be a push toward making

the process as efficient as possible.

Most energy loss in the world happens when energy is converted from on type to another. No one benefits from this lost energy and simplifying the process would the best way to utilize ever part that we can.

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