AS and A Level Biology

Describe the role of gibberellin in the germination of barley

Explain the role of auxin in elongation growth by stimulating proton pumping to acidify cell walls

Describe the rapid response of the Venus fly trap to stimulation of hairs on the lobes of modified leaves and explain how the closure of the trap is achieved

Explain the sliding filament model of muscular contraction including the roles of troponin, tropomyosin, calcium ions and ATP

Describe the ultrastructure of striated muscle with reference to sarcomere structure using electron micrographs and diagrams

Describe the roles of neuromuscular junctions, the T-tubule system and sarcoplasmic reticulum in stimulating contraction in striated muscle

Describe the structure of a cholinergic synapse and explain how it functions, including the role of calcium ions

Explain the importance of the refractory period in determining the frequency of impulses

Describe and explain the rapid transmission of an impulse in a myelinated neurone with reference to saltatory conduction

Describe and explain changes to the membrane potential of neurones, including: • how the resting potential is maintained • the events that occur during an action potential • how the resting potential is restored during the refractory period