In cells that are constantly involved in secretion, an equivalent amount of membrane must be returned to the interior of the cell for each vesicle that fuses with the plasma membrane; if this does not occur, then what would happen?

       The cell membrane would keep expanding in a way that could lead into a process called apoptosis.

Explanation:

       As said on the question, in secretion, the same amount of membrane must return to the cell, because, when a cell wants to send something to outside of it, it needs to have a membrane involving it for protection, and the organelle that does that is the Golgi Apparatus.

      Once it involves this thing that needs to go outside the cell, this Golgi will be less larger than before, and the plasmatic membrane will be bigger once the exocytosis happen, and if it keeps expanding and not going back, the golgi apparatus would stop working and this cell would program its own death by the apoptosis process.

hydroxyl -oh

alcohols, always polar, can form hydrogen bonds with h2o molecules

carboxyl -cooh  

cargoxylic acids, has acidic properties which is a source of hydrogen ions, found in cells in ionized for with a charge of oh-1

carbonyl > co

ketone if within skeleton, aldehyde if group is at the end of skeleton, k & a may be structural isomers, it determines 2 sugars (ketose & aldose)

amino -nh2

amines, acts as a base, it can pick up h+ ions from surrounding solution, ionized with charge of 1+

methyl ch2

addition to rna/dna affects and gene expression

phosphate -opo3 ²⁻

organic phosphates, contributes to negative charge to, molecule that it is a part of, and potential to react with h20

sulfhydryl -sh

thiols, cross-linking stabilize the protein, and it is structure

it cools slower in the earth meaning the crystals have more time to form than lava on the surface