Answer:
Explanation:
The cell membrane separates the cell from the outer environment. The extracellular fluid contains the sodium ions (Na+), chloride ions (Cl-), while intracellular fluid contains potassium (K +) and negative anions.
The potential difference arises when the membrane is selectively permeable to some ions. The resting potential is -70mV.
When the neurons get excited, the sodium ions start to enter by sodium channels.
Now there are more positive ions inside the cell membrane. It disturbs the resting potential i.e. -70mV. This stage is known as depolarization.
When the inside environment of the cell is more positively charged, the potassium ions start to move out of the cell. It goes out by the voltage-gated channels. Thus resting stage is maintained and it is known as repolarization.
But the initial stability of the cell membrane has to be maintained. To restore the resting stage, the sodium ions start to move out of the membrane and potassium ions enter into the cells again. This is an active transport and has done by the Na+ - K+ pump. Here 3 sodium ions move out and 2 potassium ions pumped into the cell through the plasma membrane.
Thus the resting potential regains. The potassium ions come back into the cells against the concentration gradient and ATP provides the energy for this phenomena.
the three kinds of nitrogenous wastes based on the energy required to synthesize them are arranged; Ammonia < urea < uric acid.
Nitrogenous wastes are the nitrogen compounds that organisms use to get rid of excess nitrogen. Ammonia, urea, and uric acid are the most common nitrogenous wastes that animals excrete. Protein metabolism generates all of these nitrogenous wastes.
Ammonia is the most toxic of these nitrogenous wastes, and it is the most common but requires the least energy. Urea is more harmful than uric acid, but it is less harmful than ammonia, reducing the amount of energy required to synthesize it. Uric acid is the least harmful, a non-poisonous particle with four nitrogen molecules. This is useful for birds and reptiles that lay hard eggs because it eliminates the most nitrogen, uses the least amount of water, and is not toxic. It also takes the most energy input.
Know more about urea here: brainly.com/question/14453829
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