What are living things made of, and how do animal and plant cells differ?
Identify the parts of animal and plant cells and their functions, compare the two cell types, and describe how cells are organised into tissues, organs and systems
A focused N(A)-Level answer on cells. The parts of animal and plant cells and their jobs, the differences between them, and how cells build up into tissues, organs and systems.
Reviewed by: AI editorial process; not yet individually human-reviewed
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What this dot point is asking
SEAB wants you to identify the main parts of animal and plant cells and their functions, to compare the two cell types, and to describe how cells are organised into tissues, organs and organ systems. The central idea is that the cell is the basic building block of all living things, and many cells working together make a whole organism.
The answer
Parts of an animal cell
All animal cells share these parts:
- cell membrane: a thin layer that controls what enters and leaves the cell,
- cytoplasm: a jelly-like substance where chemical reactions happen,
- nucleus: controls the cell's activities and contains the genetic information (DNA),
- mitochondria: where respiration releases energy.
Parts of a plant cell
Plant cells have all the animal-cell parts plus three extra structures:
- cell wall: a tough outer layer made of cellulose that supports and shapes the cell,
- chloroplasts: contain chlorophyll and carry out photosynthesis,
- large permanent vacuole: a fluid-filled space that keeps the cell firm.
Comparing the two cell types
The key differences are that plant cells have a cell wall, chloroplasts and a large permanent vacuole, while animal cells do not. Both have a cell membrane, cytoplasm, a nucleus and mitochondria.
Levels of organisation
In larger living things, cells are organised into bigger structures:
- cells: the basic unit (for example a muscle cell),
- tissues: groups of similar cells working together (for example muscle tissue),
- organs: groups of tissues working together (for example the heart),
- organ systems: groups of organs working together (for example the circulatory system),
- organism: all the systems together make a complete living thing.
Examples in context
Example 1. Why a leaf is green but a root is not. Leaf cells are packed with chloroplasts to carry out photosynthesis, which makes them green. Root cells have no chloroplasts because they are underground and receive no light, so roots are usually pale.
Example 2. How the stomach fits the levels of organisation. The stomach is an organ made of several tissues, including muscle tissue that churns food and lining tissue that releases digestive juices. The stomach works with other organs as part of the digestive system.
Try this
- Cue. Name the part of the cell that controls what enters and leaves. The cell membrane.
- Cue. State one structure found in plant cells but not animal cells. The cell wall (or chloroplast, or large vacuole).
- Cue. Put in order from smallest: organ, cell, organ system, tissue. Cell, tissue, organ, organ system.
Exam-style practice questions
Practice questions written in the style of SEAB exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.
Original4 marks(a) Name two parts found in a plant cell but not in an animal cell. (b) State the function of the cell membrane and the nucleus.Show worked answer →
(a) Any two of: cell wall, chloroplast, large permanent vacuole.
(b) The cell membrane controls what substances enter and leave the cell. The nucleus controls the activities of the cell and contains the genetic information (DNA).
What markers reward: two correct plant-only structures, the membrane controlling entry and exit, and the nucleus controlling the cell and holding the genetic material.
Original3 marksPut these in order from smallest to largest: organ, cell, tissue, organ system. Then define a tissue.Show worked answer →
Order from smallest to largest: cell, tissue, organ, organ system.
A tissue is a group of similar cells working together to carry out a particular job.
What markers reward: the correct order of organisation, and a tissue defined as a group of similar cells with a shared function.
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