<prompt> Secretory vesicles are transported -Along concentration gradientAgainst concentration gradientMay be along or against concentration gradientHave no relation with concentration gradient  <response>: Ans. is d i.e., Have no relation with concentration gradientExoevtosiso Exoevtosis is a reverse of endocytosis. This process is involved when secretory granules are extruded from the cell. When secretory vesicle comes in contact with inside of cell membrane, the membrane of the vesicle fuses with cell membrane and then there is extrusion of the contents of vesicle from the cells as secretory granules. Similar to endocytosis exoevtosis requires Ca and energy. Exoevtosis is also called emiocytosis or reverse pinoevtosis.o Exoevtosis secretion from the cell occurs via two pathways : -Non-constitutivepathway:- Proteins from the Golgi apparatus initially enter secretory granules, where processing of prohormones to mature hormones occurs before exocytosis. This pathway is sometimes called regulated pathway.Constitutive pathway :- Involves the prompt transport of proteins to the cell membrane in vesicles, with little or no processing or storage.Types of transport across cell membrane Carrier protein involvedEnergy requiredConcentration gradientSimple diffusionNoNoAlong Down hillOsmosis Diffusion of H.ONoNoAlong Down hillFacilitated diffusionYesNoAlong Down hillActive transportYesYesAgainst UphillExocytosisNoYesNA not applicableEndocytosisy Pinocytosis Phagocytosisy Receptor mediated endocytosisNoYesYesYesNANA 