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Flip to reveal answersHow many different amino acids build human proteins?
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All 12 Flashcards — Essential amino acids and diet
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Question
How many different amino acids build human proteins?
Answer
**20** — about **nine** are essential and about **eleven** are non-essential.
Question
Define an essential amino acid.
Answer
An amino acid the body **cannot synthesise (make)**, so it **must be obtained from the diet**.
Question
Define a non-essential amino acid.
Answer
An amino acid the body **can synthesise (make)** for itself, so it **does not have to be supplied by the diet**.
Question
Does 'non-essential' mean an amino acid is unimportant?
Answer
**No** — every amino acid is needed to build proteins. 'Non-essential' only means it is **not required in the diet**, because the body can make it.
Question
What does 'synthesise' mean here?
Answer
To **make / build** a molecule inside the body from simpler materials.
Question
Which type of amino acid must come from food?
Answer
**Essential** amino acids — the body cannot make them.
Question
How do you distinguish essential from non-essential amino acids?
Answer
**Essential = cannot be made by the body → must be eaten**; **non-essential = can be made by the body → need not be eaten**.
Question
Why can most animal proteins supply protein needs in one food?
Answer
They contain **all nine essential amino acids** in a single source (meat, fish, eggs, dairy).
Question
Why is a single plant protein sometimes not enough?
Answer
A single plant protein often **lacks one or more essential amino acids**.
Question
What must a vegan / plant-based eater do for protein?
Answer
**Combine different plant proteins** (e.g. rice + beans) so that **all nine essential amino acids** are supplied.
Question
What happens if an essential amino acid is missing from the diet?
Answer
The body has **no source** of it, so it **cannot build the proteins** that contain it (a protein deficiency).
Question
A table marks an amino acid 'essential' — what can you conclude about how to get it?
Answer
It **cannot be synthesised by the body**, so it **must be obtained from the diet**.
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Full study notes for Essential amino acids and diet
Topic 2.2 hub
Proteins
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