Organs are made up of many tissues
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.
Answer:
1. Fossil evidence
2. Homologous similarities.
3. Molecular evidence
Answer:
Phenotypic plasticity in yeast cells is beneficial because this allows the yeast to change its phenotype of being a male or female. This plasticity depends on the type of pheromone exposure. The ability to change phenotype increases the reproductive success of yeast cells. This condition is useful for yeast, especially if they must adapt to changes affecting their reproduction and survival. By having phenotypic plasticity, the yeast can continue to grow its population size.
