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How do nerve impulses travel within a nerve cell?

The membrane of all nerve cells maintains a potential difference of -70mV by pumping positive Na+ ions out of the cell. This is called the resting potential. A nerve impulse is a change in this potential - a...
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Answered by Felix W. • Biology tutor
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Describe the control of heart rate

1.) First starts in the sino-atrial node. 2.) Sino-atrial node sends out regular waves of electricity to the atrial walls in order to initiate heart beat.3.) This leads to contraction of right and left atria...
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Answered by Cian T. • Biology tutor
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Explain how an electrochemical gradient is formed in the mitochondria, and how this gradient is used to synthesise ATP.

At the first proton pump and associated electron carrier of the inner mitochondrial membrane reduced NAD releases two H + ions and two electrons. An electron travels down a series of electron carriers, each ...
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Answered by Laurence Z. • Biology tutor
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Explain why multicellular organisms needs to develop a specialised exchange system and transport system, yet unicellular organisms do not

Unicellular organisms have a large surface area to volume that is one cell thick, therefore they have a short diffusion distance and are metabolically inactive. Therefore, they can obtain sufficient oxygen a...
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Answered by Deepika K. • Biology tutor
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State 3 organelles found in a Eukaryotic cell and the functions of each organelle.

The organelles present in a Eukaryotic cell and there functions are the following: The Nucleus - the nucleus controls all the cells activities, it houses the DNA. Rough Endoplasmic Reticulum - The Rough Endo...
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Answered by Katrina B. • Biology tutor
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