Final answer:
The removal of water from cells in a scanning electron microscope can destroy cell structure because water is crucial for maintaining cell shape, and is associated with every macromolecule in the cell, stabilizing their structures and functions.
Step-by-step explanation:
The removal of water from a specimen to be observed in a scanning electron microscope (SEM) can have a destructive effect on cell structure for several reasons, but primarily because of two key factors. Firstly, water constitutes a very high percentage of the weight of living cells, playing a crucial role in maintaining the shape and structure of the cells.
When water is removed, it can lead to collapse and distortion of these structures. Secondly, water is present in association with virtually every macromolecule in the cell, including proteins, nucleic acids, and carbohydrates. This association is essential for the stability and function of these macromolecules, and its removal can disrupt their native conformations, leading to structural damage at the molecular level.