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9. Photosynthesis

Introduction to Photosynthesis

9. Photosynthesis

Introduction to Photosynthesis

1

concept

Introduction to Photosynthesis

3m

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in this video, we're going to begin our introduction to photosynthesis. And so photosynthesis is the process that uses energy from sunlight in order to synthesize or build sugars such as glucose. And really, you can see that within the word photosynthesis itself, because the root photo is a route that refers to light, such as sunlight and, of course, synthesis. Here, you can see, refers to the ability to synthesize or build something, and in this case it's going to be sugars such as glucose. Now as well. See down below. In our image, the process of photosynthesis uses carbon dioxide, gas or CO. Two from the atmosphere water, or H 20 and light energy or sunlight. And it uses those three things to make glucose, whose chemical formula is C six, H 12, 06 and oxygen gas, whose chemical formula is 02 and recall from our previous lesson videos. When we introduce different organelles that the chloroplasts are green organelles that function as the site of photo synthesis and so photosynthesis is associated with chloroplasts. Whereas cellular respiration we know from our previous lesson videos is associated with mitochondria and also recall from our previous lesson videos that photosynthetic organisms or organisms that are capable of performing photosynthesis are also called auto troughs. And this is because auto troughs are able to make their own food without having to consume other living organisms. And so auto troughs, uh, include photosynthetic organisms. And so let's take a look at our example image down below to look at the overall chemical equation for photosynthesis. And so, in this image down below, which you'll notice is that over here on the left, we have the organ L that is the chloroplast, and so when we zoom into the chloroplast, we can see that it really functions as the site of photosynthesis. And so this chemical equation that you see here for photosynthesis is going to take place really within the chloroplast. And so, as we mentioned up above and our lesson, photosynthesis is going to take carbon dioxide, gas or CO. Two from the atmosphere water or H 20 and sunlight or solar energy, which comes from the sun. And it's able to convert these three relatively simple react into here into sugars such as glucose, for instance. So here we have glucose and glucose is chemical formula is C six h 12, 06 But also oxygen gas is also created as a byproduct. And so this oxygen gas would either be released into the environment by the plant. Or it would be used by the plant itself to perform cellular respiration. And so this year concludes our brief introduction to photosynthesis and will continue to talk more and more about photosynthesis as we move forward in our course. So I'll see you all in our next video.

2

Problem

Problem

The main product of photosynthesis is:
a) Glucose.
b) Oxygen.
c) Carbon dioxide.
d) Water.
e) Sunlight.

A

Glucose.

B

Oxygen.

C

Carbon dioxide.

D

Water.

E

Sunlight.

3

concept

Photosynthesis is a Redox Reaction

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in this video, we're going to talk about how photosynthesis is really just a Redox reaction, which recall from our previous lesson videos just means that it involves the transfer of electrons between molecules. And so, once again, the overall chemical equation for photosynthesis is a redox reaction and recall from our previous lesson videos, Redox reactions We can remember by remembering Leo the Lion goes Girl. And that's because Leo reminds us of substances that lose Electrons are oxidized, whereas substances that gain electrons are reduced. And so, if you remember Leo, the lion goes girl, you'll be good on the Redox reactions. And so, really, photosynthesis is a redox reaction, and what we'll see is that by the end of the process of photosynthesis, carbon dioxide or CO. Two is going to get reduced. And so that means that it is going to gain electrons, whereas water, on the other hand, we'll see, is going to get oxidized, which means that water is going to lose electrons. And so let's take a look at our example image down below at the chemical equation for photosynthesis to get a better understanding of this. And so what you'll notice is that over here we have carbon dioxide gas, which is one of the reactions of photosynthesis. And it turns out that there's six carbon dioxide gasses, molecules that are going to react, and there are also going to be six water molecules that are gonna react. And so the carbon dioxide water and sunlight or solar energy are the reactant, and the products are going to be a sugar such as glucose, whose chemical formula C six, H 12 06 And this is the chemical structure of glucose right here and then. Also, six oxygen gas molecules are going to be produced a swell. And so this here represents the entire process of photosynthesis. And what you'll notice is that the carbon dioxide here is actually getting reduced, meaning that it is going to gain electrons as it's used to form glucose and the oxygen. I'm sorry the water molecule here is going to get oxidized as it's converted into oxygen gas, and so that means the water molecule is going to be losing electrons. It's going to be essentially providing or supplying the electrons that are needed to reduce carbon dioxide and form glucose, and so we'll be able to talk Mawr and Maura about photosynthesis and exactly where and how this process works. But what you'll notice is that this image here looks very similar to an image that we showed you when we talked about cellular respiration. And so, in our next video, what we're going to do is compare and contrast the chemical equation for photosynthesis with the chemical equation for cellular respiration. So I'll see you all in that video.

4

Problem

Problem

Which of the following reactants is reduced during the process of photosynthesis?
a) Oxygen gas.
b) Photons of light.
c) Carbon Dioxide.
d) Water.

A

Oxygen gas.

B

Photons of light.

C

Carbon dioxide.

D

Water.

5

concept

Photosynthesis vs. Cellular Respiration

7m

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in this video, we're going to compare and contrast photosynthesis versus cellular respiration. And so what you may have noticed is that photosynthesis and cellular respiration seem kind of similar when you compare their chemical equations. And so it turns out that photosynthesis and cellular respiration are both very ancient pathways that have been around for billions of years, and they're actually really highly connected to one another. And this is because each process produces the reactant that are necessary for the other process. And so, for example, photosynthesis produces products that are used as the reactions for cellular respiration, and cellular respiration produces products that are used as the reactant for photosynthesis. And so we'll be able to see this down below in our image. And also, it turns out that photosynthesis and cellular respiration are almost exactly the opposite of each other in terms of their overall chemical equations, and we'll be able to see that down below in our image as well. And so, in our example, we're gonna be looking at the connection between cellular respiration and photosynthesis. And so taking a look at this top half of the image up here, notice that it's occurring inside of the chloroplasts organelles. And so this is, of course, the chemical equation for photosynthesis that we recently talked about in our last lesson video. And so, of course, photosynthesis is going to take carbon dioxide water and sunlight energy from the atmosphere and convert those things into sugars such as glucose and oxygen gas as a by product. But what you'll notice is that the products here of photosynthesis, which are glucose and oxygen, are actually used by mitochondria. And so you'll notice that glucose and oxygen here are being used by the mitochondria. And one thing to note about this image here of the mitochondria is that it's actually flipped around. Eso that the reactant air here on the right and the arrow notices going from right toe left here. So these over here are the products of what is known as cellular respiration, which we already covered in our previous lesson videos. And so what you'll notice is that the reactant is here of the mitochondria of cellular respiration. Um, are the products of photosynthesis, and you'll see that cellular respiration converts oxygen and glucose and converts them into the products of carbon dioxide, water and a lot of a teepee energy. And so what you'll notice here is that carbon dioxide and water are products of cellular respiration, but they're actually used as the reactant for photo synthesis. And so you can see how the, uh, each process is going to produce the reactant that air needed for the other process. Now, you can also see that these two equations the equations for photosynthesis and the equation for cellular respiration are almost exactly opposites of each other. And so the reason for that is because notice that carbon dioxide, water and energy are all reactant for photosynthesis, whereas carbon dioxide, water and energy are all products for cellular respiration. Remember their products because the arrows going from right toe left here and which will also notice, is that in photosynthesis, glucose and oxygen, our products for photosynthesis. But glucose and oxygen are reacting. It's for cellular respiration. And so, really, when you compare these two equations side by side, they do line up really, really similarly and really, the Onley difference where they don't line up so similarly is the type of energy that's used or produced cellular respiration is gonna be producing ATP, whereas photosynthesis is you using solar energy or sunlight energy. And so another thing that you'll notice is that, uh, the substances in terms of being oxidized or reduced our flip as well. And so notice that in photosynthesis carbon dioxide is being reduced to glucose. But notice down below. In cellular respiration, glucose is being oxidized to carbon dioxide. So there's the flip there and then also in photosynthesis, water is being oxidized to oxygen, whereas down below in cellular respiration, oxygen is being reduced to water. And so they are reverse in that respect. And so one thing that helps me remember how which substances are oxidized and reduced is that I know that photosynthesis is going to be synthesizing something and that is, God going to be a glucose molecule. Glucose is going to be synthesized. It's gonna be synthesized using carbon dioxide. It's literally able to take carbon dioxide gas from the atmosphere and use that carbon dioxide gas to build a glucose. And glucose has a lot more chemical bonds in it than carbon dioxide. And so these chemical bonds are gonna be made using electrons, and so carbon dioxide is gonna need to gain Ah, lot of electrons, or it's gonna need to be reduced in order to be used to create glucose. So this helps me remember that carbon dioxide has to be reduced. It has to gain a lot of electrons for it to make all of the chemical bonds that are found in glucose and, uh, ultimately water eyes going to be oxidized. That means that water is going to be losing electrons and being used to produce oxygen now in cellular respiration. I know that glucose has a lot of chemical bonds in it and glucose because it has a lot of chemical bonds in it. It needs to be broken down. It needs to be stripped of electrons. It needs to lose electrons, and when it loses electrons, it's going to be converted into carbon dioxide. And ultimately, the oxygen here we know is gonna act as the final electron, except er in cellular respiration. And so the oxygen, because it's acting as the final electron, except er, it's going to be gaining the electrons or it's going to be reduced and be converted into water. And so those are some ways to help you remember that photosynthesis and cellular respiration are very similar to each other, almost exact opposites. And once again, the only difference is that there is sunlight, energy here but down below. There's a teepee energy here, and other than that, they are pretty much exactly the opposite of each other. Now this here concludes our comparison of photosynthesis and cellular respiration, and we'll be able to get some practice as we move forward in our course. And we'll also continue to talk more and more about photosynthesis, so I'll see you all in our next video.

6

Problem

Problem

Energy used to power photosynthesis & ultimately cellular respiration originates from which energy source?
a) Glucose.
b) ATP.
c) Carbon dioxide.
d) The sun.

A

Glucose.

B

ATP.

C

Carbon dioxide.

D

The sun.

Additional resources for Introduction to Photosynthesis

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