describe the principles of cell signalling using the example of the control of blood glucose concentration by glucagon, limited to: • binding of hormone to cell surface receptor causing conformational change • activation of G-protein leading to stimulation of adenylyl cyclase • formation of the second messenger, cyclic AMP (cAMP) • activation of protein kinase A by cAMP leading to initiation of an enzyme cascade • amplification of the signal through the enzyme cascade as a result of activation of more and more enzymes by phosphorylation • cellular response in which the final enzyme in the pathway is activated, catalysing the breakdown of glycogen

describe the role of red blood cells in transporting oxygen and carbon dioxide with reference to the roles of: • haemoglobin • carbonic anhydrase • the formation of haemoglobinic acid • the formation of carbaminohaemoglobin

recognise and draw red blood cells, monocytes, neutrophils and lymphocytes from microscope slides, photomicrographs and electron micrographs