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Outline the "Sliding Filament Theory" of muscle contraction.

In the resting state, the myosin heads have a partially hydrolysed ATP molecule (ADP + Pi) giving them potential energy. When there is an influx of calcium ions as a result of sarcolemma depolarisation, the ...
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Answered by Sohail M. • Biology tutor
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How do alveoli create a surface for efficient gas exchange?

This kind of question is extremely common in A level biology, they want you to explain a system and apply your knowledge of biological principals to it. To understand alveoli we need to understand the concep...
MC
Answered by Matthew C. • Biology tutor
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Explain how the human eye has both high sensitivity and high acuity.

The human eye has high sensitivity because many rods connect to a singular neurone, so many weak generator potentials combine to reach the threshold and trigger an action potential. The human eye has a high ...
AM
Answered by Anna M. • Biology tutor
4638 Views

What is the difference between the lock-and-key model and the induced-fit hypothesis of enzyme action?

The lock-and-key model and the induced-fit hypothesis are two potential models for how substrates may bind in the active site of an enzyme. The lock-and-key model suggests that the substrate is completely co...
PJ
Answered by Prachy J. • Biology tutor
99023 Views

How does ATP store energy?

ATP has 3 phosphate groups. Their bonds are unstable and so have a low activation energy, which means they are easily broken. When they break by the addition of water during a hydrolysis reaction, they relea...
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Answered by Lara I. • Biology tutor
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