Answer:
enzyme are protein that speed chemical reaction ..
In the DNA, that is why they are called the building blocks of life.
Answer:
option B) intracellular receptors are present only in target cells.
Explanation:
The cell membrane or plasma membrane is composed of phospholipids and thus hydrophobic in nature, this allows the lipid soluble signaling molecules to cross the membrane. The cell membrane of all cells consist of phospholipids thus hydrophobicity of each cell membrane allows lipid soluble signaling molecules to pass through the plasma membrane. The testosterone cross the membranes of all cells but affect only target cells because of intracellular recepters that are located in target cell. The binding of signaling molecules to recepter generates a response. Thus, option B is correct.
