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socalgal2 5 hours ago

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

bilsbie 4 hours ago | parent | next [-]

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.

al_borland 4 hours ago | parent | next [-]

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.

saulpw 4 hours ago | parent | prev | next [-]

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

ErroneousBosh 4 hours ago | parent | prev [-]

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.

graypegg 5 hours ago | parent | prev | next [-]

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!

knappa 4 hours ago | parent | next [-]

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

otherme123 5 hours ago | parent | prev | next [-]

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.

limbero 5 hours ago | parent | prev [-]

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

jackmalpo 4 hours ago | parent | prev [-]

skeletal muscle cells can be many cm in length

otherme123 4 hours ago | parent [-]

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