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How Do Plants ‘Eat’?

In one of our favourite Disney classics, ‘The Lion King’, King Mufasa talks to his son, Simba.

“Everything you see exists together in a delicate balance,” he says.

“As king, you need to understand that balance and respect all the creatures, from the crawling ant to the leaping antelope.”

“But, dad, don’t we eat the antelope?” Simba asks, confused.

“Yes, Simba.” Mufasa responds, “but let me explain. When we die, our bodies become the grass, and the antelope eat the grass, and so we are all connected in the great Circle of Life.”

This is an excellent lesson for all of us and it helps us to understand our place in the great ‘circle of life.’ Because we are just a cog in the wheel of this great, huge universe, it’s important for us to understand how everything works and how it all fits together. Even the tiniest details are important for our survival. For example, how does a tiny little seed get nourished and grow into a delicious pumpkin that we can eat?

In order for us to eat, we have to understand how plants ‘eat?’

How DO plants ‘eat?’

Is that a question you have ever pondered? Can you imagine a garden flower tying a napkin around their little stem and tucking into a Sunday Roast?

Plant nutrition is not as literal as that, but plants do have to ‘eat’ and it’s important that we understand how.

We rely on plants for so much including fruits, vegetables, grains, potatoes and even the air we breathe. If we understand how plants eat, we can ensure they continue to receive the nourishment THEY need, in order to provide us with the nourishment WE need.

In order to understand basic plant nutrition, we need to understand an important term:


Photosynthesis is the process by which plants manufacture carbohydrates from raw materials using energy from light. Through a long series of chemical reactions, plants will create the energy they need from air (C02), water (H20) and light.

To simplify the process, it can be summarised like this:

Carbon dioxide, water and light go in.

Glucose, water and oxygen come out.


There is an important green pigment in the structure of the leaf that allows for the process of ‘photosynthesis’ to take place. Without it, it would not be possible. We call this pigment Chlorophyll and it can be found in the membranes of leaves. Chlorophyll helps the plants to absorb energy from light. You will find Chlorophyll in all green plants and algae.

Limiting Factors

Just as we need to keep warm in the winter and cool in the summer, and have enough air to breathe, plants need the conditions to be just right if they are to survive optimally and photosynthesize.

There are three main factors which limit the rate of photosynthesis, thereby limiting the plants ability to nourish itself.

These are:

  1. Temperature.

  2. Light intensity.

  3. Carbon dioxide concentration.

We call these ‘Limiting Factors’ and its important we understand them so we can ensure they are controlled so the plants can survive. A limiting factor can be defined as ‘something present in the environment in such short supply that it restricts life processes.’

Because of the study of Biology, we now understand how to control these limiting factors. Farmers use this knowledge to help them grow better crops. By controlling these factors, they do not have to be at their mercy to keep produce healthy. They can control each factor by growing their plants in greenhouses to maximise efficiency. This means a better harvest for the farmers which also means more food for us!

Inside a greenhouse (a glass house), conditions can be manipulated to increase the rate of photosynthesis.

This is done through:

  1. Temperature: Artificial heating

  2. Light Intensity: Artificial lighting

  3. Carbon Dioxide Concentration: Because plants are not limited to the cycle of the sun, they can photosynthesise for longer, thereby increasing the carbon dioxide content of the air inside the greenhouse.


When it comes to our nutrition, we need minerals in our foods to keep us healthy. Plants need them too. They need them to germinate, grow, fight off diseases and pests and to reproduce.

Studying Biology at ME Education

At ME Education, we follow the Cambridge IGCSE™ Syllabus, where we teach students all about Biology and important concepts such as plant nutrition.

It’s not about studying for the sake of it. The Cambridge system prepares students for life. Learning about these important concepts arms them with the knowledge they need to understand the world around them and helps them develop an informed curiosity and a lasting passion for learning.

To find out more about our approach to learning, contact our admissions team at +852 2383 0300 or on WhatsApp: +852 9866 6265 for more information.


"ME Education has helped immeasurably with the transition of my daughter coming from an overseas school to get her levels up to a Hong Kong standard. They have been very flexible in creating a suitable program that suits all involved, and the one on one training has been excellent! With special thanks to Mr. Adeel, her Biology assessment scores have been greatly improved!”

— Mrs. Chan


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