Where does this come from, and can I check it?

Mammalian red cells eject it to make room for more oxygen carrying protein. The figure is taken from Centers for Disease Control and Prevention, which is linked in full on this page. Every fact on Mondo Knows names its source rather than repeating an unsourced claim.

Is this really a science fact?

Yes. It sits on the Science shelf, one of 2,600 sourced facts grouped into space, animals, the human body, history, science and more. Category pages collect every fact in the same field.

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The links under the fact point to a quiz, game, puzzle or calculator on the same subject, and the shelf below shows related facts. The wording here is original, and quoted phrases are marked as quotations.

Mondo Knows Facts

Mature red blood cells have no nucleus

Mammalian red cells eject it to make room for more oxygen carrying protein During development a red blood cell expels its nucleus and most organelles, leaving a biconcave disc packed with haemoglobin. Without a nucleus it cannot repair itself, so it circulates for about 120 days before being broken down. The biconcave shape raises surface area for gas exchange and helps the cell squeeze through capillaries. It sits in Mondo's science collection, one of 200 facts that each trace back to the reference below.

Where this comes from

Centers for Disease Control and Prevention

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Tags: biology, cells, blood

Mature red blood cells have no nucleus: the short answers

Where does this come from, and can I check it?: Mammalian red cells eject it to make room for more oxygen carrying protein. The figure is taken from Centers for Disease Control and Prevention, which is linked in full on this page. Every fact on Mondo Knows names its source rather than repeating an unsourced claim.
Is this really a science fact?: Yes. It sits on the Science shelf, one of 2,600 sourced facts grouped into space, animals, the human body, history, science and more. Category pages collect every fact in the same field.
What else can I read about it?: The links under the fact point to a quiz, game, puzzle or calculator on the same subject, and the shelf below shows related facts. The wording here is original, and quoted phrases are marked as quotations.