Eubacteria – Structure, Nutrition & MCQs for NEET | NCERT Class 11

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Introduction

Eubacteria are also known as true bacteria. They are the most common and widely distributed prokaryotic organisms found in soil, water, air and inside living organisms. This topic belongs to Class 11 Biology – Biological Classification and is extremely important for NEET, especially for MCQs based on structure, nutrition and examples.

Students who prefer video explanation can watch the lecture first. NCERT-based notes are given below.

📑 Table of Contents

What are Eubacteria?

Eubacteria are unicellular, prokaryotic organisms having a rigid cell wall made of peptidoglycan. They are called true bacteria because they show all typical bacterial features.

NCERT Line:
“Eubacteria are the true bacteria.”

General Characteristics of Eubacteria

1. Cellular Organisation

  • Unicellular
  • Prokaryotic
  • No true nucleus
  • Genetic material present as naked DNA

2. Cell Wall

  • Cell wall made of peptidoglycan
  • Provides shape and protection

3. Habitat

  • Soil
  • Water
  • Air
  • Inside plants and animals

4. Reproduction

  • Asexual reproduction
  • Main method: Binary fission

Structure of Eubacterial Cell

  • Cell wall (peptidoglycan)
  • Plasma membrane
  • Cytoplasm
  • Ribosomes (70S)
  • Nucleoid (DNA)
  • Flagella (in motile forms)

NEET Point: Eubacteria do not have membrane-bound organelles.

Mode of Nutrition in Eubacteria

1. Autotrophic Nutrition

  • Photosynthetic – Cyanobacteria
  • Chemosynthetic – Nitrosomonas, Nitrobacter

2. Heterotrophic Nutrition

  • Saprophytic
  • Parasitic
  • Symbiotic

Special Forms of Eubacteria (NCERT)

1. Cyanobacteria (Blue Green Algae)

  • Photosynthetic eubacteria
  • Contain chlorophyll-a
  • Fix atmospheric nitrogen

Examples: Nostoc, Anabaena

2. Chemosynthetic Bacteria

  • Oxidise inorganic substances
  • Release energy
  • Important in nutrient recycling

Examples: Nitrosomonas, Nitrobacter

Importance of Eubacteria

  • Decomposition of organic matter
  • Nitrogen fixation
  • Used in curd, cheese and antibiotics
  • Some cause diseases

MCQs on Eubacteria for NEET

Q1. Cell wall of eubacteria is made of:

A. Cellulose
B. Chitin
C. Peptidoglycan
D. Silica

Answer: C

Q2. Which bacteria perform photosynthesis?

A. Mycoplasma
B. Cyanobacteria
C. Methanogens
D. Halophiles

Answer: B

Q3. Chemosynthetic bacteria obtain energy from:

A. Sunlight
B. Organic food
C. Inorganic substances
D. Oxygen

Answer: C

Q4. Nitrogen fixation is performed by:

A. Virus
B. Fungi
C. Cyanobacteria
D. Protozoa

Answer: C

Quick Revision

  • Eubacteria → True bacteria
  • Cell wall → Peptidoglycan
  • Cyanobacteria → Photosynthetic
  • Reproduction → Binary fission
  • Ribosome → 70S

Conclusion

Eubacteria are the most widespread and diverse group of prokaryotes. For NEET aspirants, strict focus on NCERT keywords like peptidoglycan, cyanobacteria, chemosynthesis and examples can easily fetch marks from this topic.

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