Hey Taonga! Tropism involves an organism (mainly plant) growing toward or away from a stimulus. Taxis involves an organism (protist or animal) moving toward a stimulus.
Answer:
1. Survivors of the pesticide have a gene that protects them from it.
2. Then the survivors pass on the gene to their offspring,
3. Each time the pesticide is sprayed, the insects have a greater chance of survival.
Photosynthetic organisms, also known as photoautotrophs, are organisms that are capable of photosynthesis. Some of these organisms include higher plants, some protists (algae and euglena), and bacteria.
Answer:
Facilitated diffusion involves transport protein
Explanation:
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.
