Cells: The Building Blocks of Life
All living things are made of cells — the smallest unit of life. Plant cells and animal cells share some features but also have important differences.
What You Need to Know
Key Concept Diagram
The cell membrane controls what enters and leaves the cell; it is present in all cells
The nucleus contains DNA (genetic instructions) that controls the cell's activities
Plant cells have a cell wall (rigid support), chloroplasts (for photosynthesis), and a large vacuole
Animal cells have no cell wall or chloroplasts, but have many small vacuoles and lysosomes
Key Vocabulary
Cell membrane
A thin, flexible layer surrounding all cells that controls the movement of substances in and out
Nucleus
The control centre of a cell, containing DNA that directs cell activities
Chloroplast
A structure in plant cells that contains chlorophyll and carries out photosynthesis
Cell wall
A rigid outer layer made of cellulose, found in plant cells but not animal cells
Knowledge Check
Select the correct answer for each question. Click "Check Answer" to see if you are right.
Question 1
Which structure is found in plant cells but NOT in animal cells?
Question 2
What is the function of the nucleus in a cell?
Question 3
Which structure carries out photosynthesis in plant cells?
Key Concepts Summary
- ●The cell membrane controls what enters and leaves the cell; it is present in all cells
- ●The nucleus contains DNA (genetic instructions) that controls the cell's activities
- ●Plant cells have a cell wall (rigid support), chloroplasts (for photosynthesis), and a large vacuole
- ●Animal cells have no cell wall or chloroplasts, but have many small vacuoles and lysosomes