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0:00
Hi guys, welcome to All CBTs. My name is Fitz and today we're going to be looking at the topic photosynthesis process. Sit back and relax. We'll be right back.
0:34
[music] Welcome back. We we're going to be looking at photosynthesis process. Now what is photosynthesis? I know we have all heard about photosynthesis. We have heard it photosynthesis. Photosynthesis. Photosynthesis. We even did it in our junior secondary school. Most of us even looked at something like that in our primary schools. But today we are going to dissect it into the simplest form.
1:04
So photosynthesis is the process by which green plants, algae and some bacteria use light energy to produce food and food is in form of glucose from carbon dioxide and water.
1:27
And we have the equation. The equation is we can see the equation 6 O2 plus H2O to give us 6 6 H2 O6 plus 602. Now when we are defining this particular topic I assure you that if you can know this equation you will not need to cram all these words. If you know that okay CO2 is for what?
1:56
CO2 is for carbon dioxide, right? Yes. H2O is for water. C6 H1206 is for our glucose and the O2 is for our oxygen. So once you you don't need to look at this, you just need to know this equation and you need to know that okay light plus chlorophyll. Then I will be able to define this as this is the um process by which green plants produce their food through carbon dioxide and water in the presence of light and chlorophyll to produce um glucose
2:34
and oxygen as the byproduct. Now if you can define it like this it is all good. So the world equation is carbon dioxide plus water to give us glucose plus oxygen in presence of light and chlorophyll.
2:54
Most people look at light there as the catalyst. Why? Because it it is what generates it initiate the the reaction. It initiates it. It is the one that gives energy. So light is the source of energy for this particular reaction to occur. So it gets the energy from the light.
3:20
Let's look at the site of photosynthesis. What does sight mean? It means that where does this photosynthesis occur? Where in the plant does it occur? Does it occur on the stem? Does it occur in the roots? Does it occur on the leaves? Does it occur in the flower? So we want to see the site of this photosynthesis. Now photosynthesis occurs in the chloroplast which contains the green pigments the chlorop that absorbs the light energy and this is all found in the leaf.
4:05
So in the leaves or in the leaf there are chloroplasts inside these leaves. Now this chloroplast they have a pigment that is called the chlorophyll. Now this chlorophyll it this chlorophyll it is the green pigment. So if you see any plant that is color that's the color green that plant has chlorophyll. That's why when we even defining it, we said all green plants is a place by which green plants manufacture. Don't even forget we
4:42
said green plants manufacture. It all comes to this. It all comes to chlorophyll because this chlorophyll it helps to absorb this light that is coming from the sun. It will trap that light and you know initiate that photosynthetic reaction that we just saw. [snorts]
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Now this is a diagram of photosynthesis. Let me try to increase it. Get the cheapest science materials from allschoolabs.com.
5:24
So this diagram we can see that this is sunlight the leaf. So we said um in the equation we said CO2 CO2 be mixed with H2O from the soil and it is going to produce sugar and oxygen.
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So let me let's look at some this explanation of this diagram.
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Sunlight. The sunlight is the energy source. The sunlight is the energy source that is needed for this equation to occur. The carbon dioxide that the CO2 it enters through the stomatter. Have you all heard of stomata? If you have not your lucky day stomats, these are microscopic openings. These are okay for let's look at this our okay
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let's say this is our leaf.
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Let's say this our leaf or these our plants.
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Let me say this our leaf
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So let's say this is don't mind my drawing please. So let's talk about if this being our leaf or let's just draw a leaf on its own. If we draw a leaf on its own we have something like this.
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You can draw a leaf on its own. So this let's say this is a leaf. You know this leaf has openings.
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They have openings. But this these openings are microscopic. We cannot see it with our naked eyes. It needs a a microscope to be seen. There are microscopic openings. So this microscopic openings CO2 will enter the leaves through these openings that call what? Sto.
8:19
So that is how the CO2 enters this leaves. [snorts] Okay. Water. Water is absorbed by the roots through the soil. So water is going to be in the soil and from that soil is going to be absorbed into the roots. That's how water gets into this plant. For the chloroplast, the chloroplast is a site of this reaction. So all this reaction is happening in the chloroplast that is located on the leaf. That's why we say that the leaf is the main site. The leaf is the site of photosynthesis.
9:01
So from this so it's going to make itself to the chloroplast and this chloroplast this reaction is going to happen in this chloroplast.
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Glucose produced as food then glucose is going to be produced as food. Don't for that equation CO2 plus H2 give us this is H12 O6 plus O2 then oxygen is going to be released as the byproduct. So the byproduct of photosynthesis is oxygen. Oxygen is a byproduct of photosynthesis.
9:41
Let's look at some stages of photosynthesis. Photosynthesis occurs in two main stages. The first stage is the light dependent reaction or we can say the light dependent stage. Now it occurs in the in the tiloid membranes. In the tyoid membranes which are you know found in chloroplast
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they require sunlight. Now it is called the light dependent phase because it requires sunlight.
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So it happens this particular light stage happens in the presence of the sun light. And why did I say the sunlight is needed? For energy for energy water is split. So let us look at what happens in this light stage. The first [laughter] thing that happens is that when this um when this sunlight when this chloroplast traps this sunlight what's going to happen that happens analogy Africa now the water is going to split H2O [snorts] will split into H+ plus O2 two.
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So during photos the water that water molecule is going to split into two. When it splits 2 H2 is going to split into 4 H+ and O2. So this O2 is what's going to be librated.
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This O2 is going to be what's going to be librated at the end. So the oxygen is going to be released. Then we're going to have hydrogen. So this hydrogen will now be added to the CO2.
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So when this hydrogen is added to the CO2 that is what will now give us our glucose that will be formed
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that's what's going to give us our glucose that will be formed that is our
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our C6 H12 06 six. So it is the CO2 that is going to the hydrogen is going to merge with the C with the CO that is going to give us this our glucose molecule and at the end of the day energy is going to be produced and NADPH is going to be produced. Now what is ATP? ATP is adinosine triphosphates.
12:45
Number two, we have the light independent reaction. It's also called the dark stage. We can also call this the dark stage reaction. And we can also call it the Calvin cycle. So when we say light independent, light independent it means it is independent of it does not need the light to occur. So it occurs in the stroma. It does not require light directly. It uses ATP and NADPH to convert the CO2 to glucose. Now the difference between this light stage and the dark stage
13:29
is that in the light stage you remember I said that the sunlight is what produces energy. Therefore the dark stage the ATP the ATP is the form of energy that will be produced. So because it does not need energy from the sunlight it will still need energy. So the energy that is going to get is the energy that was produced during the light stage and as it exists as ATP. So that ATP is going to be used for this reaction for the dark stage. So it's going to use ATP and NADPH
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and NADPH means nicotinamide adenine ducleotide phosphate. Nicotinamide adenine ducleotide phosphate. Now this NADPH is going to add hydrogen to the CO2. So the NADPH will give [snorts]
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the NA the NADPH is going to add hydrogen with this CO2 to produce glucose. So the ATP is acting as the energy
14:51
while the NADPH is adding hydrogen. So that's what is going on in the light independent stage. This process is known as the calvin cycle. So the main difference is that in the light stage it requires the sun but in the dark stage it is the energy that was produced in the light stage as ATP the alenosin triphosphate that is used as the energy in the cali cycle or in the dark stage.
15:27
Let's look at some factors affecting photosynthesis. The first factor we have is light intensity. Light intensity. So whether the light is intense or not, it affects that um reaction. So if the light is intense, it's the reaction is going to be faster. That's for the light stage. But if the light is, you know, not very intense, then reaction is going to be slow. So we can say that this that is why we call it photosynthesis. Photo photo means what?
16:00
Photo means light. So the more the light the faster the rate of the reaction by the the less intense the light is the lower and the slower the rate of this particular reaction. Number two we have is carbon dioxide concentration. So the carbon dioxide concentration will determine the yield of the glucose that is going to be gotten at the end of the day. Number three is the temperature. The temperature is also a common factor because don't forget we said the
16:32
light and the dark. So it's going to um determine whether it's going to go through a dark a light stage or dark stage. We have water availability. Without water, photosynthesis cannot occur because it needs that hydrogen and it needs that oxygen. Don't forget photosis. Number five, chlorophyll content. Why? Because this chlorophyll is what is going to trap the sunlight. That is why when you
17:01
notice all these plants that that are decolorized maybe their um leaves are already you know molted like they have um a brownish color or a yellow color they are decolorized they most of them they that's why they die they die because they cannot photosynthesize again that pigment is gone
17:22
and if you don't and if a organism does not feed what will happen it will lead to
17:34
Let's look at some importance of photosynthesis. It produces oxygen for respiration. Yes, these plants when they go through this photosynthesis. We are living things just like animals or we humans we breathe in this oxygen and we use it for respiration to produce energy in our cells. So we need this oxygen number. So it forms the base of food chains. These plants that photosynthesize they form the base of food chain. What does it mean? They produce food. They are they produce
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food. They are the producers. They are the producers. That the food chain goes like this.
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The food chain goes like this from producers
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to
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the heavy boss.
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to
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the carnivorous
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or let's just say the consumers. Let's use consumers instead. The primary consumers,
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the secondary
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consumers,
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the tertiary consumers
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and the decomposers.
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So we can the producers here they are the plants.
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So this primary consumer which are every
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so will feed on these plants. When every feed on these plants secondary consumers which are mostly carnivorous will also feed on these plants. Then I carnivor predators or we humans we fall under that tertiary
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we can feed on the plants or we can feed on the epivores we can also feed on the carnivorous animals then the decomposers now decompose them when they are dead. So at the end of the day these plants they produce food for almost the for all other organisms.
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Number three, it maintains balance of CO2 and O2 in the is the atmosphere. There must be a balance between carbon dioxide and oxygen. You know that we human beings we breathe out and or animals they breathe out CO2 but breathe in oxygen. Now if CO2 is just you know being um um respired out and is not in any use it will become excessive. So the plant uses the CO2 so that it can renew it for us and give us this oxygen that we used to breathe. Number four, it provides food and energy
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for living organisms. As we have said, it provides food directly or indirectly for organisms.
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To summarize this, photosynthesis is a vital process that converts light energy into chemical energy. The chemical energy is what? Glucose or we can say food
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and every life on earth.
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So our assignment number one question describe the process of photosynthesis including the two main stages and their functions. So you're going to describe the process of photosynthesis and there are two stages the light and the dark stage. Explain what happens there.
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The second the second assignment is number two explain the factors affecting photosynthesis and how each factor influences the rate of the process. So you're going to explain these factors that affect photosynthesis. Then you explain how for example we can say oh let me explain for water. Water is a factor that affects photosynthesis. Now you can say without water photos photosis won't occur thereby the plants cannot photosynthesize or something like that.
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When you are done with your assignments make sure you drop this your answers in our comment section. I hope you had a very nice time. I hope you learned a lot because I did. Don't forget to if you have any question to ask me, don't forget to drop your question in the comment section and don't forget to subscribe to our channel and click on the notification button to get other videos like this. Have a very nice day. See you in our next class. Goodbye.
23:08
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