That's where you get your carbons to keep producing these phosphoglyceraldehydes, or glyceraldehyde 3-phosphate. You just have this phosphate group there, but they really perform similar mechanisms. Leaves change color in autumn because plants slow down the process of photosynthesis. The dark reactions do not need photons for them to happen, although they do occur when the sun is out. But let's delve a little bit deeper and try to get into the guts of it and see if we can understand a little bit better how this actually happens. Plants are not the only organisms that use photosynthesis.
The light reactions take photons-- we're going to go into more detail about what actually occurs-- and it takes in water. And the dark reactions, for most plants we talk about, it's called the Calvin Cycle.
And let me just make a very brief overview of this. Plants contain other pigments other than chlorophyll. So water goes into the light reactions and out of the other side of the light reactions.
When I lose a hydrogen, I also lose the ability to hog that hydrogen's electron. Light-independent reactions use the energy generated during the light-dependent reactions to make carbohydrates in a process called the Calvin cycle. So just to be clear, the light reactions actually need sunlight.
You saw that in the cellular respiration videos. So let's see, I have one n, and you put an n here, and then I have two n, and I think this equation balances out. It produces-- oh, you probably saw this. The first stage of photosynthesis captures energy from the sun to break down water molecules.
Energy keeps the cycle going to repeat the process and create sugar molecules containing six carbons. Your charge is reduced when you gain an electron. So this is an overview of photosynthesis, and in the next couple of videos, I'm actually going to delve a little bit deeper and tell you about the light reactions and the dark reactions and how they actually occur. And then you have something called the dark reactions, and that's actually a bad name, because it also occurs in the light. So this is a general term for carbohydrates, but you could have many multiples of that.
Water is taken up by the roots and transported to the leaves by specialized tissue called xylem. The electrons move through the electron transport chain where they are passed along a series of proteins to eventually make ATP , the energy used in the next stage of photosynthesis. It takes six molecules of water and six molecules of carbon dioxide to make one molecule of glucose during photosynthesis.
And the process is called photosynthesis. Not that the cow is all carbohydrates, but this is essentially what is used as the fuel or the energy for all of the other important compounds that we eat. This is where we get all of our fuel. And a carbohydrate could be glucose, doesn't have to be glucose.
It gives away this hydrogen and the electron associated with it, and so the other thing gets reduced. So the light reactions need photons, and then it needs water. That this agent right here, this molecule right here, is able to give away-- now let's think about what this means-- it's able to give away this hydrogen and the electron associated with this hydrogen.
Plants are not the only organisms that use photosynthesis.
The light reactions take photons-- we're going to go into more detail about what actually occurs-- and it takes in water. So this right here, when it reacts with other things, it's a reducing agent. These single-celled organisms contain chlorophyll and are typically found in aquatic environments. Oxygen gets spit out. And then you have something called the dark reactions, and that's actually a bad name, because it also occurs in the light.