Introduction to Microbiology — Maharashtra (SSC) Class 10 Science Solutions (Free)

Microorganisms are living organisms too small to be seen by naked eye, visible only under a microscope. Four types: (1) Bacteria - single-celled prokaryotes, cell wall contains peptidoglycan, found everywhere. (2) Fungi - eukaryotic, absorb nutrients by secreting enzymes outside cells, includes molds and yeasts. (3) Protozoa - single-celled eukaryotes, can be parasitic, move using cilia or flagella. (4) Viruses - non-living, contain only DNA or RNA, replicate inside host cells.

Industrial uses of microorganisms: (1) Fermentation - bacteria and yeast produce yogurt, cheese, bread, beer, wine, vinegar by breaking down sugars. (2) Antibiotic production - fungi like Penicillium produce penicillin and other antibiotics. (3) Enzyme production - microbes produce cellulase, amylase, protease for detergents and food processing. (4) Biofuel generation - bacteria convert organic matter to biogas and ethanol. (5) Food processing - used in soy sauce, miso, tempeh production. (6) Ph…

Fermentation is anaerobic respiration by microorganisms: (1) Occurs without oxygen. (2) Glucose is broken down into pyruvate in glycolysis. (3) Pyruvate is converted to either lactate or ethanol. (4) NAD+ is regenerated to continue glycolysis. (5) Example: Lactobacillus bacteria ferment milk lactose to lactic acid, causing curdling and yogurt formation. (6) Another example: Yeast ferments glucose to ethanol and CO2 in beer and wine production. (7) Products depend on the microorganism type used.

Bacterial characteristics: (1) Prokaryotic - no nucleus or membrane-bound organelles. (2) Unicellular organisms. (3) Cell wall with peptidoglycan. (4) Reproduce asexually by binary fission (splitting into two identical cells). (5) Rapid reproduction - can divide every 20 minutes under ideal conditions. (6) Found in diverse environments - soil, water, air, organisms. (7) Beneficial in nitrogen fixation, decomposition, and disease treatment. (8) Some are pathogenic causing diseases.

Virus differences: (1) Non-living - lack cellular structure and metabolism. (2) Cannot reproduce independently outside host cells. (3) Contain only genetic material (DNA or RNA) surrounded by protein coat. (4) Much smaller than bacteria. (5) Obligate intracellular parasites - must hijack host cell machinery to replicate. (6) Cannot be treated with antibiotics. (7) Can only be eliminated through vaccines or immune response. (8) Cause diseases like influenza, measles, COVID-19.