Question

Write definitions of the following:
1 Osmosis
2 Diffusion
3 Membrane biogenesis
4 Facilitated diffusion

Answer 1

Dear Student

1. The movement of water molecules from a region of high concentration to a region of low concentration through a selectively permeable membrane is called osmosis.

2. Diffusion is the movement of particles from a region of higher concentration to a region of lower concentration.

3. Membrane biogenesis can be defined as the process of synthesis of cell membrane or plasma membrane of the cell. The cell membrane is synthesised using proteins and lipids produced in the cell. Endoplasmic reticulum plays a major role in membrane biogenesis.

4. Facilitated diffusion is a form of facilitated transport involving the passive movement of molecules along their concentration gradient, guided by the presence of another molecule – usually an integral membrane protein forming a pore or channel. Facilitated diffusion does not directly involve high-energy molecules like adenosine triphosphate (ATP) or guanosine triphosphate (GTP) since the molecules are moving along their concentration gradient.

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