In phospholipids, one of the fatty acids of a triglyceride is substituted by a phosphate-containing group
A phospholipid looks like a triglyceride, but with one fatty acid swapped out for a phosphate-containing group. This swap gives the molecule a water-attracting head and two water-repelling tails.
Real World
Every cell in your body — including the neurons firing as you revise — is enclosed in a phospholipid bilayer; without the phosphate head group substitution, no cell membrane could form.
Exam Focus
Use the word 'substituted' to match mark-scheme language — a fatty acid is replaced by a phosphate group, not 'added'.
Evaluation Scaffold
A four-step framework for high-quality evaluation. Use this for 'assess', 'evaluate', and 'to what extent' questions.
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