GCSE Biology: Blood


Plasma is a straw coloured fluid. It contains dissolves glucose, hormones, urea and dissolved gases. Plasma is the liquid which blood cells travel in.


The platelets are small fragments of dead cells that help the blood to clot. They have no nucleus and are made in bone marrow.

White blood cells

White blood cells are the bodies defence system. They produce anti-bodies and engulf incoming bacteria. This is why you do not get ill very often.

Red blood cells

The red blood cells contain haemoglobin. They are dougnut shaped with a large surface area and have no nucleus. They are the ideal transport system for oxygen around the body.