AQA · GCSE · Biology
Course version: 8461 · Version from Sept 2018
Some animals are fed high protein foods to increase growth.
Full specification wording
Farming techniques: Some animals are fed high protein foods to increase growth.
Protein is needed for growth and repair because it provides amino acids used to build new cells and tissues.
Checked against the AQA 8461 specification (opens in a new tab) on .
- Point 3 of 3
- 4 key terms
Study notes
From the checked teaching notes for this specification point.
The idea
Protein is needed for growth and repair because it provides amino acids used to build new cells and tissues. Feeding food animals a diet rich in protein supplies the amino acids needed to synthesise muscle and other body proteins, so the animals grow larger and faster. Faster growth means meat, milk or eggs can be produced sooner, which can improve the efficiency of food production. They should also note that high-protein feed can be costly and may compete with human food production, so its use involves trade-offs.
What earns the marks
- State that protein is broken down into amino acids during digestion.
- Explain that amino acids are used to build new cells and tissues for growth and repair.
- Link a high-protein diet to faster growth and greater biomass in food animals.
- Explain that faster growth can improve the efficiency of food production.
- Recognise a limitation, such as the cost of high-protein feed or competition with human food supply.
Common mistakes and how to put them right
Saying protein is used for energy rather than growth.
Put it right: Amino acids are mainly used to build new tissue, though excess protein can be respired.
Confusing growth with respiration.
Put it right: Growth involves building biomass, while respiration releases energy.
Claiming high-protein food makes animals grow without limit.
Put it right: Growth also depends on genetics, health and other dietary factors.
Exam tips
- Link protein to amino acids and then to building new tissue in a clear chain.
- Use the phrase increases growth rate and biomass when explaining the effect on food production.
- Add a balanced point about cost or sustainability if the question asks for evaluation.
Try the lesson
The start of the Farming techniques: Some animals are fed high protein foods to increase growth. lesson, made from checked teaching notes for this specification point.
Have a go first
Why are some farm animals given food that is high in protein?
Listen
Protein is needed for growth and repair because it provides amino acids used to build new cells and tissues. Feeding food animals a diet rich in protein supplies the amino acids needed to synthesise muscle and other body proteins, so the animals grow larger and faster. Faster growth means meat, milk or eggs can be produced sooner, which can improve the efficiency of food production. They should also note that high-protein feed can be costly and may compete with human food production, so its use involves trade-offs. A strong answer earns marks for these points. State that protein is broken down into amino acids during digestion. Explain that amino acids are used to build new cells and tissues for growth and repair. Link a high-protein diet to faster growth and greater biomass in food animals. Explain that faster growth can improve the efficiency of food production. A common slip: Saying protein is used for energy rather than growth. Instead, amino acids are mainly used to build new tissue, though excess protein can be respired. Exam tip: Link protein to amino acids and then to building new tissue in a clear chain.
See it
Key words
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Diet and nutrition
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Growth and biomass
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Efficiency of food production
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Sustainability trade-offs
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See every definition
- Diet and nutrition
- Protein is needed for growth and repair because it provides amino acids used to build new cells and tissues.
- Growth and biomass
- Amino acids are used to build new cells and tissues for growth and repair, and growth involves building biomass.
- Efficiency of food production
- Faster growth means meat, milk or eggs can be produced sooner, which can improve the efficiency of food production.
- Sustainability trade-offs
- High-protein feed can be costly and may compete with human food production, so its use involves trade-offs.
Label the diagram
Some boxes have lost their names. Pick the right name for each number.
1Box 1
2Box 2
3Box 3
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