Question

Which one is not connected with transport across the cell membrane?
A) Osmosis
B) Active transport
C) Diffusion
D) Surface tension

Answer 1

Hint: Cell membrane helps to control the concentration of materials inside the cell. These materials include Calcium, potassium, sodium, fatty acids, sugars and carbon dioxide which need to leave the cell.

Complete Solution:
The cell membrane is a flexible structure with back to back phospholipids present. A single phospholipid molecule contains phosphate group at the end called head and two side by side fatty acids which makes the lipid tail. Cholesterol is also present in the cell membrane which denotes the fluidity of membrane. The phospholipids are strongly packed and the membrane has a hydrophobic centre which causes the membrane to be selectively permeable. The semi permeable membrane allows the non -polar resources to move through the lipid layer. Materials like lipids, amino acids, and carbon dioxide need some help to transport across membranes. Some materials require energy, some do not. There are different techniques which help in movement of materials across membranes. Active transport is the movement of molecules like water, oxygen across the membrane against the concentration channel with the usage of energy. It is required for the gathering of molecules like glucose, ions inside the cell in high concentration. Osmosis helps in the movement of water and other solute through the semipermeable membrane. The factors which affect osmosis are the pressure potential of cell membrane and solute potential of a molecule. Diffusion is the transport of molecules from high to low concentration across a semipermeable membrane. Mainly non polar molecules are transported by simple diffusion. Surface tension is the tendency of fluid surface to maintain the possible surface area it is not connected with transport mechanism across cell membrane.

Therefore the correct answer is option D.

Note:
There are generally two types of active transport: Primary Active transport uses the energy to push molecules. Here pumps are used for molecule transfer whereas secondary active transport uses the electromagnetic gradient to move across the membrane. Here channels are made up of pore forming proteins.