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Sliding Filament Model

The muscle contracts when the actin and myosin filaments slide past each other. The myosin heads attach to the actin filaments and pull them towards the centre of the sarcomere. The H-zone and light band become narrower as the Z-lines move closer together. Lots of sarcomeres contract together to enable enough force to pull on bones and cause movement. The muscle relaxes as the sarcomeres return to their original position.

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Specification: AQA Biology (7402), A-level, 3.6.3 Skeletal muscles are stimulated to contract by nerves and act as. Topic: Muscles.

Key terms in this lesson

glycolysis: The first stage of respiration, occurring in the cytoplasm, in which glucose is split into two molecules of pyruvate with a net yield of 2 ATP and reduced NAD.
pyruvate: The three-carbon end product of glycolysis, which enters the mitochondrion for the link reaction in the presence of oxygen or is reduced to lactate or ethanol in its absence.
electron transport chain: A series of protein complexes in the inner mitochondrial (or thylakoid) membrane that pass electrons along a chain of redox reactions, pumping protons across the membrane to generate a proton gradient.

More in Muscles

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