AQA · GCSE · Biology
Course version: 8461 · Version from Sept 2018
Active transport: This requires energy from respiration.
Active transport requires energy because substances are moved against a concentration gradient, from a more dilute solution to a more concentrated solution.
Checked against the AQA 8461 specification (opens in a new tab) on .
- Point 2 of 6
- 4 key terms
Study notes
From the checked teaching notes for this specification point.
The idea
Active transport requires energy because substances are moved against a concentration gradient, from a more dilute solution to a more concentrated solution. The energy comes from respiration, which releases energy from glucose in cells. This energy is used by carrier proteins in the cell membrane to change shape and transport specific substances across the membrane. Without respiration, active transport stops. This explains why cells that carry out a lot of active transport, such as root hair cells and cells lining the small intestine, have many mitochondria to release energy by aerobic respiration. It also explains why active transport is affected by factors that affect respiration, such as oxygen availability and temperature, within limits.
What earns the marks
- State that active transport requires energy released by respiration.
- Explain that energy is needed because substances are moved against a concentration gradient.
- Link the energy to carrier proteins in the membrane, which use energy to transport specific substances.
- Describe how cells specialised for active transport, such as root hair cells, contain many mitochondria to supply energy.
- Explain that if respiration is inhibited, active transport cannot continue.
- Relate energy demand to factors affecting respiration, such as oxygen supply and temperature.
Common mistakes and how to put them right
Saying active transport uses energy from photosynthesis.
Put it right by stating that respiration releases the energy used by cells for active transport.
Thinking energy is used to make substances move faster by diffusion.
Put it right by explaining that energy is used to move substances against a concentration gradient via carrier proteins.
Ignoring the role of mitochondria.
Put it right by linking cells with high active transport demands to a high number of mitochondria.
Exam tips
- When explaining why active transport needs energy, always refer to movement against a concentration gradient.
- Link energy to respiration and mitochondria, as this shows understanding of cellular energy supply.
- If asked about adaptations, mention that cells with high active transport have many mitochondria to release more energy.
Try the lesson
The start of the Active transport: This requires energy from respiration. lesson, made from checked teaching notes for this specification point.
Have a go first
Which process supplies the energy needed for active transport in a cell?
Listen
Active transport requires energy because substances are moved against a concentration gradient, from a more dilute solution to a more concentrated solution. The energy comes from respiration, which releases energy from glucose in cells. This energy is used by carrier proteins in the cell membrane to change shape and transport specific substances across the membrane. Without respiration, active transport stops. This explains why cells that carry out a lot of active transport, such as root hair cells and cells lining the small intestine, have many mitochondria to release energy by aerobic respiration. It also explains why active transport is affected by factors that affect respiration, such as oxygen availability and temperature, within limits. A strong answer earns marks for these points. State that active transport requires energy released by respiration. Explain that energy is needed because substances are moved against a concentration gradient. Link the energy to carrier proteins in the membrane, which use energy to transport specific substances. Describe how cells specialised for active transport, such as root hair cells, contain many mitochondria to supply energy. A common slip: Saying active transport uses energy from photosynthesis. Instead, stating that respiration releases the energy used by cells for active transport. Exam tip: When explaining why active transport needs energy, always refer to movement against a concentration gradient.
Key words
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Respiration and energy transfer
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Carrier proteins and membrane transport
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Concentration gradients
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Cell specialisation and mitochondria
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See every definition
- Respiration and energy transfer
- The process that releases energy from glucose in cells, and this energy is required for active transport.
- Carrier proteins and membrane transport
- Proteins in the cell membrane that use energy to change shape and transport specific substances across the membrane.
- Concentration gradients
- Substances are moved against a concentration gradient, from a more dilute solution to a more concentrated solution.
- Cell specialisation and mitochondria
- Cells that carry out a lot of active transport have many mitochondria to release energy by aerobic respiration.
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