Microbiology is the scientific study of microorganisms, which are organisms and infectious agents that are too small to be seen clearly without the aid of microscopes or other magnification tool

Prions are infectious agents composed solely of misfolded proteins, lacking DNA or RNA. They cause neurodegenerative diseases by inducing normally folded host proteins to adopt the abnormal prion conformation, leading to protein aggregation and neuronal damage. This mechanism results in progressive, fatal disorders affecting the brain and nervous system. In humans, Creutzfeldt-Jakob Disease (CJD) is a key example, while in animals, scrapie in sheep and bovine spongiform encephalopathy (“mad cow disease”) are notable prion diseases. Prions are resistant to standard sterilization procedures, making them particularly challenging to control in medical and agricultural settings.

Yeasts are unicellular fungi that reproduce primarily through a process called budding, in which a small daughter cell forms as an outgrowth of the parent cell and eventually detaches. Some yeasts can also reproduce by fission, but budding is the most common method. Yeasts differ from molds, which are multicellular and form filamentous hyphae. As unicellular organisms, yeasts are capable of rapid growth in nutrient-rich environments and are responsible for both beneficial processes, such as fermentation in food and beverage production, and pathogenic infections in humans.