What is a staple food?

It is a food eaten regularly and in large enough quantity to supply a major part of a population's energy and nutrient intake.

Why are cereals used as staple crops throughout the world?

They give a high yield of energy per hectare, the grain dries to a low water content so it can be stored for months without refrigeration and transported easily, and between them the species grow in climates ranging from the wet tropics to cool temperate regions.

Which nutrient makes up most of a cereal grain, and in which tissue is it stored?

Starch, stored in the endosperm.

Why does the tonnage of maize grown greatly exceed the amount people eat?

A large share of the crop is used for animal feed and for industrial products such as biofuel and sweeteners, and that demand competes directly with its use as human food.

OCR A-Level Biology B H422

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Plant Reproduction

Cereals as staple foods

3 things to know
Components 01, 02 and 03

Overview

Recall questions on staple foods and why rice, wheat and maize dominate, starch in the endosperm, the nutritional risks of a single-cereal diet and milling, combining cereals with legumes, threats to cereal-based food security, the environmental costs of intensive growing, seed banks, and sustainable practices.

What you need to know

Answer each one before you reveal it.

Your recallNot started

Key term

Why is a diet based almost entirely on one cereal nutritionally risky?

Key term

What is removed when wheat is milled into white flour or rice is polished, and why does it matter?

Key term

Which three cereals dominate the world food supply, and where is each the main staple?

Questions from this subtopic

Each one with the model answer underneath.

1
What is a staple food?
Model answer
It is a food eaten regularly and in large enough quantity to supply a major part of a population's energy and nutrient intake.
2
Which three cereals dominate the world food supply, and where is each the main staple?
Model answer
Rice across much of Asia, wheat in Europe, North America and western Asia, and maize in the Americas and much of sub-Saharan Africa.
3
Why are cereals used as staple crops throughout the world?
Model answer
They give a high yield of energy per hectare, the grain dries to a low water content so it can be stored for months without refrigeration and transported easily, and between them the species grow in climates ranging from the wet tropics to cool temperate regions.
4
Which nutrient makes up most of a cereal grain, and in which tissue is it stored?
Model answer
Starch, stored in the endosperm.
5
Why does the tonnage of maize grown greatly exceed the amount people eat?
Model answer
A large share of the crop is used for animal feed and for industrial products such as biofuel and sweeteners, and that demand competes directly with its use as human food.
6
Why is a diet based almost entirely on one cereal nutritionally risky?
Model answer
Cereal protein is low in some essential amino acids such as lysine, and the grain is low in vitamin A, iron and zinc, so deficiency diseases appear unless other foods are eaten alongside it.

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