Useful and Harmful Microbes
Maharashtra Board · Class 9 · Science
Quick revision notes for Useful and Harmful Microbes — Maharashtra Board Class 9 Science. Key concepts, formulas, and definitions for last-minute revision.
Key Topics to Revise
Useful Microorganisms - Lactobacilli
- Lactobacilli are rod-shaped, anaerobic bacteria that can produce energy without oxygen
- They convert lactose (milk sugar) into lactic acid through fermentation process
- Fermentation decreases milk pH, causing protein coagulation and milk transformation into yogurt
Rhizobium - Symbiotic Bacteria
- Rhizobium bacteria live in root nodules of leguminous plants (beans, groundnut, fenugreek)
- They have a symbiotic relationship with plants - both organisms benefit
- Rhizobia convert atmospheric nitrogen into nitrates, nitrites, and amino acids for plants
Yeast - Unicellular Fungus
- Yeast is a unicellular, eukaryotic fungus with oval-shaped cells
- It reproduces asexually through budding process
- Yeast converts carbohydrates into alcohol and carbon dioxide through fermentation
Antibiotics and Their Importance
- Antibiotics are compounds from bacteria/fungi that destroy or prevent growth of harmful microorganisms
- They mainly act against bacteria, some work against protozoa
- Broad-spectrum antibiotics work against many bacteria types (ampicillin, tetracycline)
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