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.
<h2>B) option is correct </h2>
Explanation:
Natural selection is a selection pressure which operates in a population and allow the best fitted genotype to survive in changing environmental conditions and eliminate the other genotype which are not fit
In artificial selection, breeders select superior breed for the breeding purpose so that this type of selection favors the superior genotype and eliminates inferior genotype, thus leading to genetic drift
Stabilizing selection is a type of natural selection in which intermediate genotype is favored but extreme genotypes (inferior and superior) are eliminated
In the given example of pigmentation in pigeons, breeding is selectively done with intermediate pigmentation hence intermediate genotypes will be favored
Answer:
The correct answer is cholesterol is nonpolar.
Explanation:
Cholesterol is a complex lipid is synthesized from acetyl CoA.cholesterol is an important constituent of plasma membrane.
Cholesterol is non polar in nature.As a result cholesterol is repelled by water and can be found between the layers of the phospholipid in the plasma membrane.
As cholesterol is non polar it is also hydrophobic in nature.
The answer would be the hippocampus it is responsible for the formation of the nerves to make long-term memories.
The answer is; Beads of different color joined together on a piece of string
Primary structure of a protein is right after it has been translated from an mRNA by a ribosome. It is linear and has not yet been folded into a functional protein. The beads in the item represent amino acids joined together by peptide bonds.
