Course review
Review each learning objective in this topic, then open its concept explanation or question set.
Learning objective
• Receptor proteins have binding sites specific to signalling ligands • Ligand binding starts signal transduction in target cells
Start with the concept explanation, then practise to create mastery evidence.
Learning objective
• Autoinducers allow bacteria to detect population density thresholds • Vibrio fischeri bioluminescence and biofilm formation are key examples
Start with the concept explanation, then practise to create mastery evidence.
Learning objective
• Animal signals include hormones, neurotransmitters, cytokines, and Ca²⁺ ions • They differ in source, distance, speed, and target-cell response
Start with the concept explanation, then practise to create mastery evidence.
Learning objective
• Hormones include protein/peptide, steroid, and amine classes • Neurotransmitters include acetylcholine, amino acids, peptides, amines, and nitric oxide
Start with the concept explanation, then practise to create mastery evidence.
Learning objective
• Neurotransmitters act locally across narrow synaptic clefts • Hormones travel through blood to distant cells with matching receptors
Start with the concept explanation, then practise to create mastery evidence.
Learning objective
• Hydrophilic ligands bind transmembrane receptors and use intracellular relays • Steroid and thyroid hormones cross membranes and bind cytoplasmic or nuclear receptors
Start with the concept explanation, then practise to create mastery evidence.
Learning objective
• Signal transduction relays, amplifies, integrates, and distributes ligand signals • Pathways use relay proteins, second messengers, phosphorylation cascades, and effectors
Start with the concept explanation, then practise to create mastery evidence.
Learning objective
• Acetylcholine can bind ligand-gated sodium channels • Sodium influx changes membrane potential and can depolarize the postsynaptic membrane
Start with the concept explanation, then practise to create mastery evidence.
Learning objective
• GPCRs are seven-helix transmembrane receptors linked to G proteins • Ligand binding causes GDP-GTP exchange and activation of effector proteins
Start with the concept explanation, then practise to create mastery evidence.
Learning objective
• Epinephrine binds adrenergic GPCRs and activates G protein signalling • Adenylyl cyclase forms cAMP, activating kinase cascades for glycogen breakdown
Start with the concept explanation, then practise to create mastery evidence.
Learning objective
• RTK ligand binding causes dimerisation and autophosphorylation • Insulin signalling moves GLUT4 vesicles to membranes and promotes glycogenesis
Start with the concept explanation, then practise to create mastery evidence.
Learning objective
• Steroid and thyroid hormones bind intracellular receptor proteins • Hormone-receptor complexes enter or act in the nucleus as transcription factors
Start with the concept explanation, then practise to create mastery evidence.
Learning objective
• Oestradiol regulates female sex characteristics and hypothalamus-pituitary targets • Progesterone from corpus luteum or placenta maintains endometrium and pregnancy
Start with the concept explanation, then practise to create mastery evidence.
Learning objective
• Positive feedback amplifies responses, such as ethylene in fruit ripening • Negative feedback restores stability, such as insulin lowering blood glucose
Start with the concept explanation, then practise to create mastery evidence.