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Explain how an action potential is generated

At rest the neuron has a charge of -70mV, this is called the resting membrane potential and is caused by different concentrations of ions inside and out of the cell. At rest, potassium ions accumulate ins...

Answered by Charlotte S. Biology tutor
2660 Views

What is the difference between xylem and phloem tubes?

Xylem passively and unidirectionally transports water (by osmosis) from the roots to the leaves of a plant, whereas phloem uses active transport to bidirectionally transport food from the leaves to growin...

Answered by Taha S. Biology tutor
4334 Views

Describe and explain how cell fractionation and ultracentrifugation can be used to isolate mitochondria from a suspension of animal cells.

It is possible to separate out the different organelles of a cell by spinning a homogenised solution of them at different speeds using an ultracentrifuge. The cells must first be placed in a cold, isotoni...

Answered by Kate W. Biology tutor
30385 Views

Explain how blood glucose levels are controlled in the body of someone who does not have diabetes.

If blood sugar levels are too high insulin is released from the pancreas so glucose is moved into cells. If blood sugar levels are too low glucagon is released and stimulates conversion of glycogen to glu...

Answered by Isabelle L. Biology tutor
10089 Views

What is the significance of performing mouth-to-mouth breaths during CPR?

Exhaled air contains a higher percentage of CO2 than inhaled air, due to it being a waste product of respiration. By breathing excess CO2 into the patient, the blood acidity will decrease and will be dete...

Answered by Phoebe D. Biology tutor
1975 Views

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