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Comment by socalgal2 | Hacker News Reader

Cells are small? compared to what? An ostrich egg is a single cell

I never bought into the egg thing. There’s clearly a distinct cell in the center that’s going to divide and grow inside the egg. The egg itself isn’t undergoing mitosis.

The yolk is an energy/vitamin source, not a 'cell'. The division happens outside the yolk.

From Wikipedia:

> The yolk is not living cell material like protoplasm, but largely passive material

I had to go look this up, as I had heard the egg thing my whole life and just accepted it.

It turns out the oocyte is the single cell inside the egg, which for birds is significantly larger than a typical cell. So in that respect, the cell in a bird egg is very large. However, compared to the egg itself, it's tiny. The yolk and whites in the egg are all to provide nutrients as it grows, if fertilized.

One of the fascinating things about biology I think is this - that if the cells of your body were the size of an egg, they'd be way, way too big and you'd probably die.

I also find it interesting that if your spleen were to go prompt critical, it would irradiate you and you'd probably die. That is my favorite fact about nuclear physics.

What does that even mean? :D

Wouldn't this be true about any organ?

Another fun fact: if your ears were tomatoes, you'd be deaf.

For sure. You should definitely avoid bioaccumulating fissionable radionuclides in your spleen, not even a tiny amount if you can help it.

I don't know for sure here, but isn't the ostrich IN the egg a multicellular animal? I would assume the first point where the egg contains anything that will become the ostrich, mitosis is happening to make more ostrich cells. I'm assuming there's always cell walls and nucleuses every step of the way here, and the egg and ostrich are never just one big cell.

I could be off base here though, I'm really channeling grade 9 bio class from decades ago!

You're correct, but only for fertilized eggs. Unfertilized eggs are single cells.

Surrounded by a bunch of stuff that isn’t the ovum. “There is at most one cell in an unfertilized bird egg” is not the same as “an unfertilized bird egg is one cell and nothing more”.

The trick is that the egg is a ball with one small cell (the ovum) that happens to have also a huge reservoir of food for the future ostrich. There is a moment when there is only once cell in the egg, just after the fussion of the ovum and the sperm cell.

Unfertilized bird eggs are single cells, fertilized eggs should be multicellular by the time they are laid.

skeletal muscle cells can be many cm in length

A neuron can be more than 1 meter long in humans, more than 20 meter in a whale.

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