It looks correct to me. Good job
Answer:
But what does “waxing and waning gibbous” mean? Rob says crescent is when you can see less than half of the moon illuminated. “Gibbous, you attach that to either waxing or waning when you see more than half of the moon illuminated,” he said. Waxing means it's getting bigger while waning means it's getting smaller.
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.
Answer: The lock-and-key mechanism is usually associated with the complementary shapes of an enzyme with a single substrate wherein the lock that is being referred to is the enzyme and the substrate is the key. One right sized substrate (key) fits into the active site (key hole) of the enzyme (lock).
