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:
c. Proteins
Explanation:
A stretch of DNA that code for specific proteins is said to be a gene. A gene is transcribed into mRNA. The mRNA has a nucleotide sequence complementary to the corresponding gene. The nucleotide sequence of mRNA is read in the form of genetic codes during the process of protein synthesis to specify the amino acid sequence of proteins. Therefore, genes carry the genetic information for the assembly of proteins and the processes of transcription and translation deliver the stored genetic information.
Answer:
B. phagocytes
Explanation:
Phagocytosis is a process wherein a cell binds to the item it wants to engulf on the cell surface and draws the item inward while engulfing around it. The process of phagocytosis often happens when the cell is trying to destroy something, like a virus or an infected cell, and is often used by immune system cells.
The answer is (B. levothyroxine)
That would be called evolution or in more scientific terms: T<span>he change in the inherited characteristics of biological populations over successive generations. :p
Hope this helps!
</span>
