Plant, Animal and Bacterial Cells
~8 min read
- Plant vs animal: Plants have cell wall, chloroplast and large central vacuole. Animals have centrosome and lysosomes.
- Bacterial cell: Prokaryote — no nucleus, no membrane-bound organelles, peptidoglycan cell wall.
- Antibiotics: Penicillin blocks bacterial cell wall synthesis — does not harm animal cells.
This topic builds on cell biology by contrasting the three major cell types. CDS/OTA frequently asks what is and isn't present in each — especially regarding the cell wall and antibiotics.
Three Cell Types Compared
| Feature | Plant | Animal | Bacterial |
|---|---|---|---|
| Nucleus | Yes (membrane-bound) | Yes (membrane-bound) | No — nucleoid only |
| Cell wall | Cellulose | Absent | Peptidoglycan |
| Chloroplast | Yes | No | No (photosynthetic bacteria use membranous vesicles) |
| Central vacuole | Large | Small or absent | Absent |
| Mitochondria | Yes | Yes | No |
| Lysosome | Rare | Yes | No |
| Centrosome | No | Yes | No |
| Storage carbohydrate | Starch | Glycogen | Glycogen (some) |
| Ribosome size | 80S | 80S | 70S |
Antibiotics and Bacterial Targets
- Antibiotics exploit features unique to bacterial cells that animal cells lack.
- Penicillin blocks synthesis of the peptidoglycan cell wall — bacterium bursts under osmotic pressure. Safe for humans because our cells have no cell wall.
- Other antibiotics target bacterial protein synthesis at 70S ribosome (e.g. streptomycin, tetracycline) — our 80S ribosomes are unaffected.
- Some block bacterial DNA replication or folate metabolism (sulfa drugs).
- Animal viruses (influenza, HIV) are not affected by antibiotics — they lack cell walls and ribosomes.
Important Variations
- Fungi: have cell walls but made of chitin, not cellulose.
- Mycoplasma: smallest known bacteria; lack a cell wall — unaffected by penicillin.
- Photosynthetic prokaryotes (cyanobacteria): chlorophyll lies on membranous vesicles, not plastids.
- Starch vs glycogen: starch stored in plant cells; glycogen in animal liver and muscle.
CDS/OTA PYQ Examples
Q: Which one is correct?
(a) Prokaryotic cells possess nucleus (b) Cell membrane present in both plant and animal cells (c) Mitochondria and chloroplasts not found in eukaryotic cells (d) Ribosomes are in eukaryotic cells only
Answer: (b) Cell membrane is present in all cells. [CDS-I 2015]
Q: Penicillin inhibits synthesis of bacterial:
(a) cell wall (b) protein (c) RNA (d) DNA
Answer: (a) Cell wall (peptidoglycan layer). [CDS-II 2015]
Q: Cell wall is not present in cells of:
(a) Bacteria (b) Plants (c) Fungi (d) Humans
Answer: (d) Humans — no animal cell has a cell wall. [CDS-I 2021]
Q: Cell wall is absent in which organism?
(a) Bacteria (b) Diatom (c) Mushroom (d) Tapeworm
Answer: (d) Tapeworm — it's an animal. [CDS-II 2023]
Q: Which one of the following statements about starch and glycogen is correct?
(a) Both in plant cells (b) Both in animal cells (c) Starch in plant, glycogen in animal (d) Both in plant and animal
Answer: (c) Starch in plant cells; glycogen in animal cells. [CDS-II 2022]
Q: Chlorophyll in photosynthetic prokaryotic bacteria is associated with:
(a) plastids (b) membranous vesicles (c) nucleoids (d) chromosomes
Answer: (b) Membranous vesicles — prokaryotes have no plastids. [CDS-II 2019]
Drill Plant, Animal and Bacterial Cells for CDS/OTA
CDS/OTA-pattern items on Plant, Animal and Bacterial Cells with answer keys and explanations.
Start Free Mock TestFrequently Asked Questions
Why don't antibiotics work against viruses?
Viruses are not cells — they lack the cell wall, ribosomes and metabolic machinery that antibiotics target. Antiviral drugs are different in mechanism.
What makes fungi different from plants?
Fungi have chitin (not cellulose) in their cell walls, lack chloroplasts, and obtain food by absorbing organic matter — they are heterotrophs.
Which cell organelle is found in plant cells but not animals?
Chloroplast and large central vacuole. Plant cells also have a cellulose cell wall; animal cells have a centrosome that plants lack.