Place the events listed below in the chronological order as they occur in the co
ID: 3483619 • Letter: P
Question
Place the events listed below in the chronological order as they occur in the contraction of a sarcomere according to the "sliding filament" model. ATP binds to myosin activating the myosin [Choose ] Ca+ binds to the thin filament IChoose ] actin binding sites exposed Choose ] myosin binds to actin Choose ] myosin "heads" pull thin filament toward center of sarcomere Choose ] ATP on myosin converted to ADP ADP stays bound to myosin. Choose ] new ATP binds to myosin released an·myosin activated. Choose] If Cat still present cycle starts again Choose 4Explanation / Answer
A nerve impulse arrive at a neuromuscular junction which causes release of chemical called acetylcholine.The presence of acetylcholine causes depolarisation of motor- end plate which travel throughout the muscle causing transverse tubule, causing calcium to be released from sarcoplasmic reticulum that is calcium bimds to thin filament.
In presence if high concentration of calcium, calcium binds to troponin and also changes its shape and so moving tropomyosin from active site of Actin. The myosin now attach to actin and forming a cross bridge.
The breakdown of ATP releases energy which enable myosin to pull the actin filaments inwards and so shortening the muscle.This occur along entire length of myofibril in the muscle cell.
The myosin detaches from the actin and the crossbridge is broken when the ATP molecules binds to myosin head.When the ATP is broken down the myosin head can attach to actin binding site further along actin filament and further along the actin filament and repeat the powerstroke.
This process of muscular contraction can last for as long as their is adequate ATP and calcium stores.Once the impulse stops the calcium ions is pumped back to sarcoplasmic reticulum and actin returns to its resting position causing muscle to lengthen and relax.