Nonspecific permeases
allow only water to cross the cytoplasmic membrane.
allow a variety of molecules to cross the cytoplasmic membrane.
allow only one type of solute to pass through the membrane.
are not used for passive transport.
The Correct Answer and Explanation is :
The correct answer is: allow a variety of molecules to cross the cytoplasmic membrane.
Explanation:
Nonspecific permeases are proteins embedded in the cytoplasmic membrane of cells that facilitate the transport of a variety of molecules across the membrane. These permeases are involved in passive transport, meaning they allow molecules to pass through the membrane down their concentration gradient (from high concentration to low concentration) without the need for energy expenditure.
These permeases differ from specific permeases in that they do not select for just one particular molecule or ion. Instead, they are capable of transporting a broad range of molecules, typically small, polar, or uncharged molecules like sugars, amino acids, and ions. The primary function of nonspecific permeases is to enhance the permeability of the membrane to a variety of molecules, which helps the cell maintain homeostasis by facilitating the exchange of substances between the internal and external environments.
An important characteristic of nonspecific permeases is that they are integral membrane proteins, often forming channels or carriers that provide a pathway for molecules to pass through the hydrophobic core of the lipid bilayer. These permeases do not require the energy of ATP, as they work by diffusion, a process that depends on the concentration gradient of the molecule being transported.
For example, some nonspecific permeases in bacteria and eukaryotic cells can allow small molecules like water, glycerol, or various ions to diffuse through the membrane. The fact that they do not specifically bind to one molecule but allow a range of substances makes them crucial for various physiological processes, like nutrient uptake and waste removal in cells.
Now, I will generate an image to visually represent how nonspecific permeases work in a membrane.
Here is the diagram of a cytoplasmic membrane with nonspecific permeases, showing how various molecules like water, glucose, and ions move through the membrane. The permeases are represented as protein channels or carriers, facilitating the movement of these molecules.
