Mycoplasma are the smallest living cells known so far and are unique among bacteria because they lack a cell wall. According to NCERT Class 11 Biology (Biological Classification), mycoplasma are pleomorphic organisms capable of surviving without a rigid cell wall. This topic is highly important for NEET, especially for direct MCQs.
Students who prefer video explanation can watch the lecture first. NCERT-based notes are given below.
📑 Table of Contents
- What is Mycoplasma?
- General Characteristics of Mycoplasma
- Structure of Mycoplasma
- Mode of Nutrition
- Reproduction in Mycoplasma
- Importance of Mycoplasma
- MCQs on Mycoplasma for NEET
- Quick Revision
- Conclusion
What is Mycoplasma?
Mycoplasma are a group of prokaryotic organisms that belong to Kingdom Monera. They are characterised by the absence of a cell wall and are capable of surviving in a wide range of environments.
NCERT Line:
“Mycoplasma are the smallest living cells known and can survive without a cell wall.”
General Characteristics of Mycoplasma
1. Size and Shape
- Smallest living cells
- Pleomorphic (variable shape)
- Size ranges from 0.1–0.3 µm
2. Cell Wall (Most Important)
- Cell wall absent
- Hence resistant to antibiotics like penicillin
NEET Point: Absence of cell wall is the most important identifying feature.
3. Cellular Organisation
- Unicellular
- Prokaryotic
- No true nucleus
- No membrane-bound organelles
4. Habitat
- Soil
- Sewage
- Plants and animals
- Some are pathogenic
Structure of Mycoplasma
- Plasma membrane (rich in sterols)
- Cytoplasm
- Ribosomes (70S)
- Nucleoid (DNA)
NEET Tip: Presence of sterols in plasma membrane provides strength.
Mode of Nutrition
- Mostly heterotrophic
- Parasitic or saprophytic
- Absorb nutrients directly from host
Reproduction in Mycoplasma
- Asexual reproduction
- Binary fission
- Sometimes by fragmentation
Importance of Mycoplasma
- Cause diseases in plants and animals
- Responsible for plant diseases like little leaf of brinjal
- Used in biological research
MCQs on Mycoplasma for NEET
Q1. Mycoplasma are known as:
A. Largest cells
B. Smallest living cells
C. Eukaryotic cells
D. Multicellular organisms
Answer: B
Q2. Which structure is absent in Mycoplasma?
A. Plasma membrane
B. Ribosomes
C. Cell wall
D. DNA
Answer: C
Q3. Mycoplasma show resistance to penicillin because:
A. Thick cell wall
B. Absence of nucleus
C. Absence of cell wall
D. Presence of sterols
Answer: C
Q4. Shape of Mycoplasma is:
A. Rod shaped
B. Spherical
C. Spiral
D. Pleomorphic
Answer: D
Quick Revision
- Mycoplasma → Smallest living cell
- Cell wall → Absent
- Shape → Pleomorphic
- Nutrition → Heterotrophic
- Reproduction → Binary fission
Conclusion
Mycoplasma are unique prokaryotes that lack a cell wall and show pleomorphism. For NEET aspirants, remembering keywords like smallest living cell, no cell wall, pleomorphic and penicillin resistance is extremely important for scoring questions from Biological Classification.