Assimilation
Exam-ready definition
The movement of digested food molecules into the cells of the body where they are used, becoming part of the cells.
How this is marked
The paying idea is that absorbed molecules are taken into cells and used or built into the cell, not simply absorbed across the gut wall (that is absorption). A classic mark point: amino acids are assimilated and used to build proteins, and glucose is assimilated and used in respiration. Drop a mark by treating assimilation as a synonym for absorption.
In an exam answer
On protein in the diet: 'After absorption, amino acids are assimilated into the cells where they are built up into new proteins for growth and repair.'
Full topic guide: Human nutrition