Lecture on Microorganisms: Friend and Foe

Introduction

Lecturer: Aishwarya
Chapter: Microorganisms: Friend and Foe
Goal: Cover entire chapter in one go as part of a 45-day mission for midterms
Notable points:
- Recap of previous champion series on microorganisms
- Encouragement to check previous detailed sessions
- Encouragement to register for Akash National Talent Hunt Exam (ANTHE)
- Mention of Baiju's Mini Learning Program and Worksheet Series

Microorganisms are tiny organisms not visible to the naked eye; hence, 'micro'
Require a microscope to observe
Found everywhere: air, water, soil, extreme conditions (hot springs, snowy mountains, salty lakes)
Termed as cosmopolitan due to their omnipresence
Definition: Microscopic organisms or tiny organisms

Four major groups:
- Bacteria: Unicellular, different shapes (bacilli, cocci, vibrio, spirula)
- Fungi: Found on dead/decaying matter (e.g., yeast, mushroom)
- Protozoa: E.g., amoeba, paramecium
- Algae: Aquatic (e.g., chlamydomonas, giant kelp)
Viruses:
- Not considered true living organisms
- Have both living and non-living characteristics
- Depend on host cells to reproduce

Curd Formation:
- Involves lactobacillus bacteria converting lactose in milk to lactic acid
- Lactic acid acts on milk proteins, leading to curd formation
Fermentation:
- Yeast breaks down sugars anaerobically to produce alcohol and CO2
- Used in bread making (rising of dough), wine production
- Definition: Conversion of sugar into alcohol

Antibiotics:
- Chemical substances obtained from microorganisms that kill/inhibit other microbes
- Examples: Penicillin, streptomycin, tetracycline, erythromycin
- Discovered by Alexander Fleming in 1929 (penicillin)
- Ineffective against viral diseases
- Precautions: Take under medical supervision, complete course, avoid overuse
Vaccines:
- Biological preparation of dead/weakened microbes stimulating immune response
- Examples: BCG, polio, tetanus vaccines
- Antibodies produced by the body to fight pathogens

Decomposition:
- Soil microbes decompose dead and decaying matter into soluble forms
Nitrogen Fixation:
- Soil microbes like rhizobium convert atmospheric nitrogen into usable forms
- Found in leguminous plant root nodules (symbiotic), also free-living (e.g., nostoc, anabaena)

Pathogens: Microorganisms causing diseases
Communicable Diseases: Spread from infected to healthy individuals
- Examples: Typhoid, tuberculosis
Non-Communicable Diseases: Do not spread between individuals
- Examples: Deficiency diseases, heart diseases
Modes of Transmission:
- Airborne, contaminated water, vectors (e.g., mosquitoes), direct contact
Examples:
- Bacterial: Typhoid, cholera, tuberculosis
- Viral: Hepatitis, chickenpox, polio
- Protozoan: Malaria
- Vector-borne: Malaria (Plasmodium via female Anopheles), Dengue (virus via female Aedes)
Diseases in Animals: Anthrax (bacteria), foot and mouth disease (virus)
Diseases in Plants: Citrus canker (bacteria), rust of wheat (fungi), yellow vein mosaic of bhindi (virus)

Chemical Methods: Use of sodium metabisulfite
Salt and Sugar: Drains moisture from microbes
Oil and Vinegar: Acts as barrier, used in pickling
Hot and Cold Treatment: Pasteurization (heating and immediately cooling milk)
Proper Storage and Packaging: Enhances shelf life
Refrigeration and Freezing: Low temperatures to inactivate microbes

78% of atmosphere is nitrogen (unusable form)
Nitrogen Fixation: Conversion of atmospheric nitrogen to soluble forms
- Carried out by lightening, biological nitrogen fixers
Process:
- Plants absorb nitrogenous compounds -> Animals consume plants -> Decomposition -> Soil bacteria convert compounds back to gaseous nitrogen

Recap of important points
Encouragement to fill worksheet, join telegram for PDFs
Reminder of the importance of staying subscribed to the channel for more educational content