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Why is ATP required for skeletal muscle contraction?

When muscles contract, the length of the sarcomere (distance between the Z-lines*) shortens. ATP is required for the process of cross-bridge cycling which enables the sarcomere to shorten. The steps of cross...
SF
Answered by Surina F. • Biology tutor
39617 Views

What is diffusion and why is it important in both animals and plants?

Diffusion is a passive process involving the movement of molecules from a region of a higher concentration to one of a lower concentration (the term passive means that the process does not require an input o...
MC
Answered by Mathew C. • Biology tutor
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Where is DNA found in a human cell? What is a gene?

DNA is a long molecule found in the nucleus (or more specifically the nucleolus) of a human cell. When it is condensed and shortened it appears, under a microscope, as 23 pairs of chromosomes. A gene is a lo...
RM
Answered by Ryan M. • Biology tutor
18754 Views

Describe the passive movement through diffusion and explain Fick's Law

Diffusion is the net passive movement of particles (atoms, ions or molecules) from a region in which they are in higher concentration to regions of lower concentration. It continues until the concentration o...
ZB
Answered by Zuzana B. • Biology tutor
48804 Views

How do muscle fibres contract?

Contraction occurs when an impulse from a motor neurone reaches the synapse at the junction with the muscle, the neuromuscular junction (NMJ). At the presynaptic membrane of the NMJ, depolarisation results i...
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Answered by Emily B. • Biology tutor
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