Whether or not a molecule can pass through the cell membrane is determined by….

Some molecules can diffuse through the cell membrane without any assistance from the cell. Others require the help of transmembrane proteins to move into or out of the cell. Three primary factors determine whether a molecule will diffuse across a cell membrane: concentration, charge and size.

Explanation:

Some molecules can diffuse through the cell membrane without any assistance from the cell. Others require the help of transmembrane proteins to move into or out of the cell. Three primary factors determine whether a molecule will diffuse across a cell membrane: concentration, charge and size.

stress fractures occur largely in the feet and legs and are common in sports that require repetitive impact, primarily running/jumping sports such as gymnastics or track and field.

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