Biology
How does iron influence cellular function?
Quick fact
Human blood is red because haemoglobin uses iron to transport oxygen.
Why this is interesting
Humans and octopuses solve the same problem — carrying oxygen — using completely different chemistry.
Read the full explanation
Understanding How does iron influence cellular function?
Haemoglobin contains iron atoms that bind with oxygen. When oxygen attaches, it changes the way the molecule absorbs and reflects light, creating the familiar red colour.
A deeper explanation
Iron-based haemoglobin is highly efficient in the conditions where humans evolved, especially warm, oxygen-rich environments. Different environments favour different biological solutions.