Microorganisms: Friend and Foe - III

Louis Pasteur discovered fermentation - the process by which microorganisms break down sugars without oxygen (anaerobic respiration). He disproved spontaneous generation and established germ theory.

Fermentation is a beneficial microbial process used in making bread, yogurt, cheese, and alcoholic beverages. Pasteurization and sterilization kill microbes, while emulsification is a physical process, not microbial.

Alexander Fleming discovered penicillin in 1928 from the Penicillium mold. This was the first true antibiotic and revolutionized medicine by treating bacterial infections.

The Gram staining technique was developed by Hans Christian Gram in 1884. This differential staining technique separates bacteria into Gram-positive and Gram-negative based on cell wall composition. Koch developed postulates, Hook worked on cells, and Leeuwenhoek was the first to observe microorganisms.

Vibrio bacteria are characterized by their distinctive comma or curved rod shape. Lactobacillus is rod-shaped, Streptococcus is spherical (cocci), and Sarcina forms cube-like clusters of 8 cells.

The female Anopheles mosquito is the biological vector or carrier that transmits Plasmodium vivax, the parasite causing one type of malaria. The mosquito picks up the parasite from an infected human and injects it into a healthy person during feeding.

Saccharomyces cerevisiae (spelled with 'cerevisiae' not 'crevisae') is a yeast fungus used in baking and brewing. Mucor, Penicillium, and Aspergillus are all molds (filamentous fungi), not yeasts which are unicellular.

Fungi, like animals, store their food reserves as glycogen. Plants store starch, while proteins and fats are not primary storage molecules in fungi. This is one of the characteristics that distinguishes fungi from plants.

Anton van Leeuwenhoek is known as the Father of Microscopy for his pioneering work in making high-quality single-lens microscopes and being the first to observe and document microorganisms like bacteria and protozoa in the 1670s.

Potato Dextrose Agar (PDA) is a standard culture medium used to grow fungi and some bacteria in Petri dishes. It provides nutrients from potato infusion and dextrose (sugar). Glucose alone lacks other nutrients, while bone marrow and blood serum are not standard solid media for Petri dish cultures.

Blue-green algae (cyanobacteria) are prokaryotes and lack membrane-bound organelles like mitochondria. Green algae, fungi, and angiosperms are all eukaryotes possessing mitochondria for cellular respiration.

Lactobacillus is a rod-shaped bacterium, as indicated by the suffix 'bacillus' which means rod. Spherical bacteria are called cocci (like Streptococcus), spiral shapes are spirochetes or spirilla, and Vibrio has a comma shape.

Blue-green algae are called cyanobacteria because they are photosynthetic bacteria containing blue-green pigments. Red algae have phycoerythrin, brown algae have fucoxanthin, and green algae have chlorophyll like plants.

Bacteriophages are viruses that specifically infect and replicate within bacteria. The word literally means 'bacteria-eater'. They are not bacteria themselves, and they target bacterial cells, not plants or insects.

Plasmodium is a protozoan parasite that causes malaria in humans. Salmonella causes food poisoning, Mycobacterium tuberculosis causes tuberculosis, and Escherichia coli can cause various infections but not malaria.

Cyanobacteria (blue-green algae) were the first organisms to perform oxygenic photosynthesis, gradually converting Earth's reducing atmosphere to an oxygen-rich one over billions of years. Monocotyledons are plants that evolved much later, while filamentous algae and mycoplasma do not produce oxygen through photosynthesis.

Spirogyra is a filamentous green alga that is multicellular, consisting of chains of cylindrical cells arranged in a filament. Chlamydomonas and Chlorella are unicellular green algae, while cyanobacteria (though they can form colonies) are fundamentally unicellular prokaryotes.

Mycoplasma are bacteria that lack a cell wall, which is their distinguishing feature. Despite this difference, they share fundamental characteristics with bacteria: they are prokaryotic, have small cells, divide by binary fission, and are susceptible to many antibiotics that target bacterial processes. They are not viruses, fungi, or protozoa.

Amoeba moves and feeds using temporary extensions of its cell membrane and cytoplasm called pseudopodia ('false feet'). Paramecium uses cilia (tiny hair-like structures) for movement, Euglena uses a flagellum (whip-like tail), and 'Algal' is not a specific organism.

Yeast (Saccharomyces cerevisiae) are fungi that ferment sugars to produce ethanol and carbon dioxide - the process used in baking, brewing, and winemaking. Amoeba and Paramecium are protists that do not perform fermentation, and Euglena is a photosynthetic/flagellated protist.