When I think of a biological cell, as a farmgirl who raises birds, I naturally think of something really small. You can't blame me because a cell's own definition specifies that it is the smallest unit capable of performing all of life's activities! An egg definitely doesn't come to mind at first thought.
I've learned that cells don't have to be small all of the time! A Xenophyophore is a single-celled organism that can grow to be nearly as big as a volleyball. It's just one cell with only one membrane!
A large 20-cm wide Xenophyophore. Xenophyophores are single cell animals called protists Source
A giraffe's nerve cell connecting its larynx to its brain can be several meters long! The egg, on the other hand, is today's largest cell on our globe!
Yes, the egg is the biggest cell produced by an organism, and it is the cell that sperm fertilizes to form a baby. And this makes perfect sense!
In animals that develop their young internally, the egg must give everything the embryo requires to nourish and energize it before it implants and begins to draw resources from its mother. As a result, that egg must be quite large!
The eggs of animals that develop into infants outside of their mothers, such as chickens and other birds, must be significantly larger since they must contain virtually everything needed to develop into a kid from beginning to end.
When an egg encounters sperm, it begins to divide, dividing one giant cell into many smaller cells, while an egg that is never fertilized does not divide. In most animals, an unfertilized egg is simply reabsorbed by the mother's body, but for species that produce large egg cells, such as birds, it's easier to simply lay an unfertilized egg rather than reabsorb the entire thing. It becomes a single cell in a shell, which is fantastic because, while it may not produce a baby, it does produce an egg-cellent breakfast!
Keep in mind that the next time you eat eggs, you're eating the largest cell on the planet! Cheers!
Posted from HypeTurf