Author: Dr. Rachana Choudhary
Volume: 01
First Online: 2026
Pages: 65-112
DOI:

This unit focuses on the structure, classification, physiology, and biological importance of bacteria and cyanobacteria. It discusses bacterial morphology, cell organization, cell wall structure, flagella, pili, capsule, reproduction, nutrition, and
classification, along with their ecological, industrial, and medical significance. The unit also explains Gram-positive and Gram-negative bacteria, bacterial growth, and genetic recombination. In addition, it introduces cyanobacteria as photosynthetic
prokaryotes, describing their cellular organization, pigments, reproduction, classification, nitrogen fixation, and ecological role. Special emphasis is placed on the contribution of cyanobacteria to soil fertility, oxygen production, and sustainable agriculture through biofertilization. The unit provides essential knowledge of prokaryotic microorganisms and their applications in agriculture, biotechnology, environmental management, and public health, enabling students to understand their diversity, physiology, and significance in natural ecosystems.