Photosynthesis explained
What photosynthesis is, the word and balanced equations, how chlorophyll changes light energy into chemical energy, and what plants do with the glucose. With Vietnamese subtitles. A “Check yourself” section with typed questions is below the video on the site.
Practice
- Check yourself: Photosynthesis explained – Type the missing words, put the steps in order and write a short answer. No multiple choice: you have to remember it. Vietnamese help for every question.
Transcript
Photosynthesis is the process that plants use to make carbohydrates. The raw materials are carbon dioxide and water. The energy comes from light.
The light is absorbed by chlorophyll, inside the chloroplasts. The products are glucose and oxygen.
Here is the word equation. Carbon dioxide plus water, in the presence of light and chlorophyll, makes glucose plus oxygen.
Here is the balanced chemical equation. Six C O two, plus six H two O, makes C six H twelve O six, plus six O two.
Let us count the atoms. On the left, there are six carbon, twelve hydrogen, and eighteen oxygen. On the right, it is the same. So the equation is balanced.
Chlorophyll absorbs light energy. This light energy is transferred into chemical energy, which is stored in the glucose molecules.
What does the plant do with the glucose? It uses it for respiration, to release energy. It makes starch, to store food. And it makes cellulose, for the cell walls.
Glucose is also changed into sucrose, so that it can be transported around the plant. And with nitrate ions, the plant makes amino acids, to build proteins.
Remember. Carbon dioxide and water make glucose and oxygen, using light. Chlorophyll changes light energy into chemical energy. It happens in the chloroplasts. And glucose is used for respiration, starch, cellulose, sucrose, and amino acids.
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