Question

Active transport across bio membrane involves
A. Production of ATP
B. Requirement of energy
C. Production of toxins
D. Release of energy

Answer 1

Bio membranes are the biological membranes that are present in our body within the cell. We have several bio membranes in our cell through which transfer of molecules takes place and have the ability to select the molecules that pass through the membrane.

Complete Answer:
- We know that cell membrane is an example for a biological membrane. It is made up of a phospholipid bilayer along with some sugars and proteins. It is also called a selectively permeable membrane as it can select the molecules to pass through the cell membrane. Transport of substances can occur in many ways. They are diffusion, facilitated transport and active transport.
- In simple diffusion, note that special membrane proteins are not required. Here, movement of substances is completely passive in nature as it requires no energy. It is purely based on the concentration gradient of the substances.
- Active transport is the mode of transport in which molecules are transported through the bio membranes against the concentration gradient. It occurs by consuming ATP and hence the name active transport. Protein pumps present in the membranes pump the molecules against the concentration gradient.
- As it has the involvement of proteins, the process is highly selective and also it can be saturated. Saturation occurs when all of the proteins are used for transporting and the rate reaches the maximum value.

Hence the correct option is B.

Note: Note that in facilitated diffusion, no energy is consumed although transport is done by special proteins present in the membrane. Here the process is downhill as the transport occurs only down the concentration gradient of the molecules. But as protein pumps are involved, the process is highly selective.