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Year 8 Photosynthesis

Photosynthesis is one of the most important processes on earth. Without it, life as we know it wouldn’t exists. Every green plant and algae do this.

Photosynthesis is used by plants and some unicellular organisms to create their own food source.

This means they are Autotrophic.


An interesting plant that you may come across is the Venus fly trap. These are carnivorous plants and although this plant eats insects, it still undergoes photosynthesis.

The insects it eats are used for nitrogen, as these plants often grow in nitrogen poor soil

Overall they are still considered autotrophs


The over all equation for photosynthesis is

Click here for more information on the requirements for photosynthesis

But where does this whole process happen? Does it happen in the whole plant? In specific cells?

It actually occurs in organelles call chloroplast. These chloroplast are found in cells, and are responsible for the plants green appearance.

Click here for more information on chloroplast

Now that you know the equation, you should understand the requirements for it.


Carbon dioxide



With out any one of these a plant can’t undergo photosynthesis

So, how does a plant get light, carbon dioxide and water?  

Click here to learn about the adaptations of a plant

Its important to understand that even though plants undergo photosynthesis, they still go through aerobic respiration.

Photosynthesis only produces glucose. Glucose is packed full of energy, but cells cant access the energy quickly from a glucose molecule. So we break down glucose through respiration into ATP.

A usable energy source.

Plants are always going through respiration, but only doing photosynthesis during the light. This means at different times of the day the plant may be producing more oxygen or Carbon dioxide.

Click here for a test on photosynthesis

Copy and complete the sentences below in your book

1. Plants use ________ to make their own food. This means they are _________. The reactants are __________ and Water. Combined with light energy this produces __________ and oxygen.

2. Explain why photosynthesis is important for all life? (2 marks)

3. What is chloroplast and what is its role in photosynthesis (3 marks)

4. Copy the image into your book and fill in the blanks


Continue bellow for some basic questions

5. Oxygen is a ________ product of photosynthesis

6. Some plants, algae and bacteria create their own food through photosynthesis or chemosynthesis. This means they are ______________ .

7. Humans get their energy by eating other animals. This mean we are __________.

teacher answers photo.doc Carbon dioxide + Water                      Glucose + Oxygen




Click here for worksheet 1

Click here for worksheet 2