Seeds come in different shapes and sizes but how do they know what kind of plant to grow into? The answer to this fantastic question about plants actually tells us about how all life on Earth works.
Inside all living creatures there is information that tells their bodies how to grow, develop and work. But what is this information and how does it create life?
The cells of all living creatures contain a biological molecule called ‘deoxyribonucleic acid’ or DNA. DNA contains a kind of code that gives living things the information they need to be alive. It is made up of chemical building blocks called nucleotides and the order in which these nucelotides join up makes the code.
The nucleotides in DNA are called adenine, thymine, cytosine and guanine (A, T, C and G for short). They link up in long chains or ‘strands’, and when two matching strands join together and twist around each other, they make a DNA molecule. You can find out more about the structure and discovery of DNA here.
But how does DNA tell a seed what to grow into? Well, the cells inside a seed all contain DNA. The code in that DNA tells the seed’s cells what to do.
When the seed is planted in the ground, its DNA will tell it how to grow into a plant. It tells it what type of plant it comes from and gives it instructions about when to grow, how to develop and how to carry out all the chemical reactions and biological processes it needs to become a plant and stay alive. Watch this short video to see how a seed germinates and grows into a plant.
Did you know that the DNA code for each type of creature is different? The four nucleotide building blocks can link up in lots of different combinations to make millions of different codes. So the code for a human isn’t the same as the code for an oak tree or a jaguar or a mushroom! There are millions of different species of living creatures on Earth and each one has its own unique DNA code.