Which of the following, A to D, is not an example of cell signalling?
The release of histamine by mast cells, which binds to H1H_1H1 receptors on nearby capillary endothelial cells to increase vascular permeability.
The passive diffusion of carbon dioxide from respiring muscle cells into the blood plasma.
Thyroxine binding to intracellular receptors in target tissues to increase the transcription of genes regulating basal metabolic rate.
Acetylcholine binding to nicotinic receptors on the sarcolemma of a skeletal muscle fibre at a neuromuscular junction.
19 exam-style questions on OCR A A Level Biology Communication and homeostasis. Each one has a worked solution and a mark scheme showing where the marks go.