Activity 6 : “Photosynthesis”

Videoclip projection: "Photosynthesis"

a) Read and translate the text before watching the video.

b) Watch the videoclip with the help of the transcription next to it.

c) Answer the questions.

a) Read and translate this text before watching the video.

The process of Photosynthesis

Photosynthesis is the process that most plants go through to make food. Plants get the raw materials (= materia prima) needed for photosynthesis from the soil (= suelo), the air, and the sun.

Where do plants get water, minerals and carbon dioxide?

When it rains, water gets absorbed into the ground. Plants take in the water, along with minerals from the soil, through their roots. In their roots, plants have tubes. These tubes, or veins, bring water and minerals from the soil to their leaves. Leaves take carbon dioxide from tiny pores, on the underside (= envés) of the leaf.

Where is the missing ingredient for photosynthesis?

Now that we have water and carbon dioxide in the leaf, are we ready for photosynthesis? Wrong! We're missing the key ingredient. Let's see the sun now, please. Now it gets really interesting.

Where does photosynthesis take place?

It is in the leaves of the plant that most of the action takes place. If we look at the leaf under a microscope, we see a layer of cells. Inside these cells are tiny nodules called chloroplasts. Chloroplasts contain a special chemical product called chlorophyll. It is chlorophyll, by the way, that gives plants a green colour.

When the light energy from the sun is captured by the chloroplast, it is stored in stacks of thycaloid membranes. It is in these membranes that the chemical reaction of photosynthesis takes place. Chlorophyll increases the speed of this process.

Can you explain the most important chemical reaction in photosynthesis?
What are the products derived from photosynthesis?
How do plants use them?

Let's take a look at this reaction. The absorbed light energy from the sun is used to join water and carbon dioxide to form glucose, or sugar. The glucose is then distributed throughout the plant as food. Oxygen is a product of this reaction which the plant doesn't need, and it's released back into the air.

And that is how most plants prepare food for themselves.

b) Watch this videoclip with the help of the transcription next to it:

Hello!

Today we are meeting outside, so we can discuss the concept of photosynthesis.

Photosynthesis is the process that most plants go through to make food. Plants get the raw materials needed for photosynthesis from the soil, the air, and the sun.

When it rains, water gets absorbed into the ground. Plants take in the water, along with minerals from the soil, through its roots. In their roots, plants have tubes called the xylem and phloem. These tubes, or veins, run throughout the plant and bring water and minerals from the soil to its leaves. Leaves bring in carbon dioxide from tiny pores, or stomata, on the underside of the leaf.

Now that we have water and carbon dioxide in the leaf, we are ready for photosynthesis, right? Wrong! We're missing the key ingredient. Let's bring out the sun now, please. Now it gets really interesting.

It is in the leaves of the plant that most of the action takes place. If we look at the leaf under a microscope, we see that right below that outer layer of cells, there is a layer of short elongated cells called palisade cells. Inside the palisade cells are tiny nodules called chloroplasts. Chloroplasts contain a special chemical called chlorophyl. It is chlorophyl, by the way, that gives plants a distinctive green colour.

When the light energy from the sun is captured by the chloroplast, it is stored in stacks of thycaloid membranes. It is in these membranes that the chemical reaction of photosynthesis takes place. Chlorophyl is the catalyst. Think of it as lining up all the molecules for the reaction.

Let's take a look at this reaction. The absorbed light energy from the sun is used to join water and carbon dioxide to form glucose, or sugar. The glucose is then distributed throughout the plant as food. Oxygen is a by-product of this reaction, and it's released back into the air.

And that is how most plants prepare food for themselves. I hope you've enjoyed this brief description of photosynthesis. And I hope to see you again soon. Good-bye!

c) Answer these questions:

1.- Where do plants get water, minerals and carbon dioxide?

2.- Which is the missing ingredient for photosynthesis in this list? Carbon dioxide, water, minerals.

3.- Where does photosynthesis take place?

4.- Can you explain the most important chemical reaction in photosynthesis?

5.- Complete the following sentences:

a) The products derived from photosynthesis are .............................. and .............................. .
b) How do plants use them?