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Describe the roles of calcium ions, ATP and phosphocreatine in producing contraction of S (b) a muscle fibre.

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BF
Answered by Bertie F. • Biology tutor
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Can you describe the path of electrical conduction through the human heart?

Special cells make a patch in the right atrium known as the sino-atrial node (SA node), these cells can depolarise themselves! When these cells depolarise, they cause depolarisation of cells nearby, these si...
AE
Answered by Alex E. • Biology tutor
3996 Views

Describe how a healthy kidney produces urine

At the Bowman's Capsule, the blood undergoes ultrafiltration. This is when the smaller molecules in the blood are forced through the partially permeable membrane of the Bowman's Capsule. This is because the ...
JJ
Answered by Jacob J. • Biology tutor
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What specialised structures do the lungs have to allow diffusion of gases?

The lungs are highly specialised. They have alveoli which are small air sacs. Alveoli give the lungs a big surface area, meaning that more oxygen can diffuse from the lungs into the blood stream, and more wa...
BH
Answered by Bethany H. • Biology tutor
15058 Views

What is a cytoskeleton? What are its main components in animal cells?

A cytoskeleton is a structure that acts as a support for the cell. It also maintains the cell shape, holds and moves organelles. It is made from a fibre network dispered in the cell cytoplasm, attached in th...
BH
Answered by Bethany H. • Biology tutor
11096 Views