(a)[1]
Explain the meaning of homeostasis.
(b(i))[1]
Insulin consists of two polypeptide chains that are produced in $\beta$ cells in the pancreas. State exactly where in $\beta$ cells polypeptide molecules are synthesised.
(b(ii))[1]
Name the process through which insulin is secreted from $\beta$ cells.
(b(iii))[3]
Describe the effects of insulin on muscle cells.
(c)[5]
During stress or very vigorous exercise, extra glucose must be released into the blood. The hormone adrenaline is secreted and binds to receptors on the cell surface membranes of liver cells. Describe how the effect of adrenaline on liver cells leads to an increase in blood glucose concentration.
(c(iii))[3]
Describe how insulin affects muscle cells.