AQA · GCSE · Biology
Course version: 8461 · Version from Sept 2018
Organs are aggregations of tissues performing specific functions.
Full specification wording
Principles of organisation: Organs are aggregations of tissues performing specific functions.
An organ is a structure made from several different tissues that work together to carry out a particular function.
Checked against the AQA 8461 specification (opens in a new tab) on .
- Point 3 of 4
- 4 key terms
Study notes
From the checked teaching notes for this specification point.
The idea
An organ is a structure made from several different tissues that work together to carry out a particular function. Because each tissue contributes a different job, the organ can perform a task that no single tissue could achieve alone. For example, the stomach contains muscular tissue to churn food, glandular tissue to secrete digestive juices, and epithelial tissue to line its inner and outer surfaces. In plants, a leaf is an organ containing palisade mesophyll tissue for photosynthesis, xylem and phloem for transport, and epidermal tissue for protection. Organs are themselves grouped into organ systems, such as the digestive system or the transport system in plants, so understanding organs helps explain how whole organisms function.
What earns the marks
- Define an organ as an aggregation of different tissues performing a specific function.
- Give named examples of organs, such as the stomach, heart, leaf or root, and state their functions.
- Identify at least two different tissues within a named organ and describe the contribution of each.
- Explain that the combination of tissues allows the organ to carry out a function that individual tissues could not perform alone.
- Place organs correctly in the hierarchy: cells form tissues, tissues form organs, organs form organ systems.
- Link organ function to the needs of the whole organism, for example the heart pumping blood to deliver oxygen and glucose.
Common mistakes and how to put them right
Describing an organ as a group of identical cells.
Put it right: An organ contains several different tissues.
Confusing an organ with an organ system.
Put it right: An organ system is a group of organs working together.
Listing tissues without linking them to the organ's function.
Put it right: Explain how each tissue contributes to the overall job of the organ.
Exam tips
- When asked about an organ, name at least two tissues and explain the role of each in the organ's function.
- Use the stomach or leaf as a prepared example, since both contain several clearly different tissues.
- Keep the hierarchy in order and use it to check that your answer places the organ at the correct level.
Try the lesson
The start of the Principles of organisation: Organs are aggregations of tissues performing specific functions. lesson, made from checked teaching notes for this specification point.
Have a go first
What is an organ? Select the correct answer.
Listen
An organ is a structure made from several different tissues that work together to carry out a particular function. Because each tissue contributes a different job, the organ can perform a task that no single tissue could achieve alone. For example, the stomach contains muscular tissue to churn food, glandular tissue to secrete digestive juices, and epithelial tissue to line its inner and outer surfaces. In plants, a leaf is an organ containing palisade mesophyll tissue for photosynthesis, xylem and phloem for transport, and epidermal tissue for protection. Organs are themselves grouped into organ systems, such as the digestive system or the transport system in plants, so understanding organs helps explain how whole organisms function. A strong answer earns marks for these points. Define an organ as an aggregation of different tissues performing a specific function. Give named examples of organs, such as the stomach, heart, leaf or root, and state their functions. Identify at least two different tissues within a named organ and describe the contribution of each. Explain that the combination of tissues allows the organ to carry out a function that individual tissues could not perform alone. A common slip: Describing an organ as a group of identical cells. Instead, an organ contains several different tissues. Exam tip: When asked about an organ, name at least two tissues and explain the role of each in the organ's function.
See it
Key words
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Organ
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Cooperation of tissues within organs
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Structure and function of animal organs
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Structure and function of plant organs
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See every definition
- Organ
- An aggregation of tissues performing specific functions, made from several different tissues that work together to carry out a particular function.
- Cooperation of tissues within organs
- Each tissue contributes a different job, so the organ can perform a task that no single tissue could achieve alone.
- Structure and function of animal organs
- The stomach contains muscular tissue to churn food, glandular tissue to secrete digestive juices, and epithelial tissue to line its inner and outer surfaces.
- Structure and function of plant organs
- A leaf contains palisade mesophyll tissue for photosynthesis, xylem and phloem for transport, and epidermal tissue for protection.
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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