Question

Can you please define the following terms in your own words, without changing the meaning of its original definition.

1. Exocytosis

2. Endocytosis

3. Pinocytosis

4. Fluid Mosaic model of cell membrane

5. Active transport

6. Passive transport

Answer 1

Exocytosis: Transport vesicles prescripted for the membrane of plasma or plasma membrane sustain fusion with the plasma membrane and salvation the contents outside the cell in the procedure called exocytosis. It is a carried out by specializedcell that called regulated secretory pathway or it may be a constitutive secretory pathway that called carried out by all cells. Antibodies released by the activated B-lymphocytes is an example of this.

Endocytosis:it is a process that eukaryotic cells are internalized the materials from their outsider environments. Scientist de Duve was coined the termed endocytosis in the year 1963. The outsider molecules are internalized by the formation of membrane bound vesicles at the plasma membrane of the cell surface. The internalized molecules are pinching off and release of free vesicles into the cytoplasm.

Pinocytosis: pinocytosis is also called cell drinking or fluid phase endocytosis. pinocytosis is a process where cell can internalized the fluid and solutes via small vesicles that diameter is less than 150nm.

Fluid Mosaic model of cell membrane: Plasma membrane are views as quasi fluid structures where proteins are injested or inserted into the lipid bilayer. it is prescribed that fluid are moved into the lipid and proteins and mosaic arrangement of proteins are embedded in to the lipid bi layer. this model was proposed by the Singer and Nicolson in the year 1972.

Active transport: it is mediated by the carrier proteins and occurs against the concentration gradient. in the process metabolic energy is used and accumulates the solutes on one side of membrane.

Passive transport: it is occurs along the concentration gradient and in the process no metabolic energy is used. it is two types one is simple diffusion and another is facilitated diffusion.