Question
Draw neat labelled diagrams of a plant cell and an animal cell. State the major differences between the two.
Solution — Step by Step
Both plant and animal cells are eukaryotic cells — they have a membrane-bound nucleus and organelles.
Structures present in BOTH:
- Cell membrane (plasma membrane) — controls what enters and exits the cell
- Nucleus — contains DNA; directs all cell activities
- Cytoplasm — gel-like fluid filling the cell; site of many chemical reactions
- Mitochondria — site of aerobic respiration; produces ATP (energy)
- Endoplasmic reticulum (ER) — rough ER (ribosomes attached; protein synthesis) and smooth ER (lipid synthesis)
- Ribosomes — site of protein synthesis
- Golgi apparatus — packaging and shipping of proteins and lipids
- Lysosomes — digestion of waste material and cellular debris
- Vacuoles — storage organelles (small and many in animal cells)
Cell wall — rigid outer layer outside the cell membrane; made of cellulose. Provides structural support and shape. Absent in animal cells.
Chloroplasts — contain chlorophyll; site of photosynthesis. Convert light energy to chemical energy (glucose). Absent in animal cells.
Large central vacuole — usually one large vacuole occupying up to 90% of cell volume in mature plant cells. Maintains turgor pressure. Animal cells have small, multiple vacuoles.
Plastids — chloroplasts (green, photosynthesis), chromoplasts (coloured, pigments), leucoplasts (white/colourless, storage). Only in plant cells.
No centrioles in most plant cells (plant cells use other structures for spindle formation in cell division).
Centrioles — cylindrical structures involved in forming the spindle fibres during cell division. Absent in most plant cells.
Lysosomes — more prominent in animal cells; contain digestive enzymes.
Small, multiple vacuoles — unlike the large central vacuole of plant cells.
No cell wall — just the flexible cell membrane, allowing various shapes.
| Feature | Plant Cell | Animal Cell |
|---|---|---|
| Cell wall | Present (cellulose) | Absent |
| Chloroplasts | Present | Absent |
| Central vacuole | Large, one (fully mature) | Small, multiple |
| Plastids | Present | Absent |
| Centrioles | Absent (most plants) | Present |
| Shape | Fixed, rectangular (due to cell wall) | Irregular, variable |
| Energy source | Can make own food (autotrophic) | Cannot; must consume food (heterotrophic) |
| Glycogen | Absent (stores starch instead) | Present |
For the animal cell diagram:
- Draw an irregular round/oval shape (cell membrane)
- Inside: large oval nucleus with nucleolus
- Mitochondria (bean-shaped) scattered throughout cytoplasm
- Small vacuoles
- ER network near nucleus
- Centrioles (two small cylinders) near nucleus
For the plant cell diagram:
- Draw a regular rectangular shape (to show cell wall)
- Cell wall (thick outer boundary) + cell membrane (inner line)
- Large central vacuole (taking up most of the space)
- Nucleus pressed to one side (by large vacuole)
- Chloroplasts (oval with inner structure) in cytoplasm
- Mitochondria present but smaller/fewer visible
- No centrioles
Labelling required for full marks: Cell wall, cell membrane, nucleus, nucleolus, mitochondria, vacuole, chloroplast (plant), centriole (animal), cytoplasm, ER (rough and smooth if possible).
Why This Works
The differences between plant and animal cells directly reflect their different lifestyles:
Plant cells have cell walls because plants don’t move — the rigid wall provides structural support that replaces the animal’s skeletal system.
Plant cells have chloroplasts because plants are autotrophs — they make their own food using light energy. Animal cells get energy by consuming other organisms.
Plant cells have large vacuoles to maintain turgor pressure (like an internal “water balloon”), keeping the plant firm and upright. When vacuoles lose water, the plant wilts.
Animal cells have centrioles because they use a different mechanism for organising the mitotic spindle during cell division.
Alternative Method — Functional Grouping of Differences
Group differences by function:
Energy/Nutrition differences:
- Chloroplasts (plant): photosynthesis
- Glycogen (animal): energy storage
- Starch (plant): energy storage
Structural differences:
- Cell wall (plant): structural rigidity
- Centrioles (animal): cell division support
Storage/regulation differences:
- Large central vacuole (plant): turgor, storage
CBSE Class 8 board exams almost always include one diagram question from this chapter — either plant cell or animal cell or both. The most commonly missed labels: nucleolus (dot inside nucleus), tonoplast (membrane around vacuole in plant cells), and plasma membrane vs cell wall in plant cell diagrams. Draw both boundary lines for the plant cell clearly.
Common Mistake
Students often draw chloroplasts in animal cells or forget to draw the cell wall in plant cells — then draw only the cell membrane. For plant cells: draw TWO boundary lines — the outer thicker one is the cell wall, the inner one is the cell membrane. For animal cells: draw ONE boundary — only the cell membrane. Mixing these up loses diagram marks.