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Stem cells are human or plant cells which can turn into (differentiate) other cell types, more specialised for their job. They often help with growth of tissues and development of embryos. Human stem cell...

An action potential depolarises the sarcoma and depolarisation travels down the T-tubules to the sarcoplasmic reticulum, which releases Ca²⁺ (calcium ions) to the sarcoplasm. Ca²⁺ ca...

Ultrafiltration occurs in the nephron, the functional unit of the kidney. Blood enters a coiled network of vessels called the glomerulus from the afferent arteriole at a high hydrostatic pressure. The glo...

There are 4 levels of structure associated with a globular protein; primary, secondary, tertiary and quarternary. The primary structure is the organisation of amino acids, bonded by peptide bonds. The sec...

How I would explain to the student:pollution of streams and rivers because of fertiliser use, open sewers into water courseexcess nutrients get washed up in water courseplants flourish using these mineral...