Photsynthesis to make food
Answer:
Active transport requires energy from ATP while facilitated diffusion does not
Explanation:
Active transport and facilitated diffusion with the use of channel and carrier proteins are both ways by which ions, polar and large molecules cross a selectively permeable membrane.
The major difference is that; Active transport transport these particles from a low to high concentration, which is against concentration gradient and hence, energy is required to perform the task
Facilitated diffusion transport from a high to low concentration, which is through a concentration gradient and hence, no energy is required to perform the task.
Answer:
The membrane potential of a nerve cell will depolarize if there is an increase in the positive ions inside the cell.
Explanation:
When nerves are in resting potential it is -70mV. In this stage interior of the cell is negatively charged and outside is more positive. When depolarization occurs the inside cell becomes positive.
This is due to the rush of sodium ions into the cell by voltage-gated channels. Now the inside charge is more positive and the chloride ions move out of the cell. Thus outside becomes more negative.
After some time of depolarization stage, potassium ions move out of the cell making the nerve cell again negative. Now the depolarized stage becomes repolarized by the entry of potassium ions.
During depolarization, the potential of the cell is -55mV. When repolarization occurs, it is again -70mV. But the potassium channels are open and some of the potassium ions move out of the cell making the inside environment more negative. This is known as hyperpolarization condition.
This hyperpolarization remains for a short period where action potential can't occur. This period is called the refractory period. Again potassium ions enter into the cell. This results in the resting potential of the neuron again.
