Red blood cell Carry oxygen. Contain haemoglobin (rich in iron) to carry oxygen. Biconcave shape to provide a large surface area for the diffusion of oxygen. No nucleus to provide more space for ...

Healthy fresh red blood cells have a distinctive biconcave – or dumbbell – shape for efficient oxygen release. During refrigerated storage, red cells become energetically stressed and more ...

Red blood cells for example, have no nucleus, so they can hold more oxygen. They're also biconcave or disc-shaped to absorb oxygen more quickly and rounded to flow easily through tiny capillaries.