MICR101A - General Veterinary Microbiology Week 1

Microbiology lecture notes covering the history, theories, fields of study, microscopy, and classification of microorganisms.

Microbiology

The study of microorganisms, which are tiny organisms that live around us and inside our body.

Organism

A living thing that ingests and breaks down food for energy and nutrients, excretes undigested food as waste, and is capable of reproduction.

Microorganism

A very, very small organism that you cannot see with your naked eye, but with a microscope.

Zacharias Janssen

Inventor of the first compound microscope in $1590$, which used two lenses inside a sliding tube.

Robert Hooke

Discovered cells in cork in $1665$ and published the book Micrographia.

Antonie van Leeuwenhoek

The first person to see living microorganisms in $1674$.

Edward Jenner

Developed the first vaccine, specifically for smallpox, in $1796$.

Louis Pasteur

Disproved spontaneous generation (biogenesis) in $1861$.

Robert Koch

Developed Germ Theory and Koch’s Postulates in the $1880\text{s}$.

Elie Metchnikoff

Discovered phagocytosis as an immune defense mechanism.

Paul Ehrlich

Proposed the "magic bullet" drug therapy concept in the $1900\text{s}$.

Alexander Fleming

Discovered penicillin, the first antibiotic, in $1929$.

Bacteriology

The study of bacteria, which are single-celled prokaryotes with no true nucleus.

Virology

The study of viruses, which are submicroscopic, non-cellular entities made of genetic material (DNA or RNA) inside a protein coat.

Mycology

The study of fungi, which are non-photosynthetic eukaryotes that include yeast and molds.

Phycology

The study of algae, which are eukaryotic, photosynthetic organisms found mostly in aquatic environments.

Protozoology

The study of protozoa, which are single-celled, animal-like microorganisms that obtain food by engulfing smaller organisms.

Big Bang Theory

The theory suggesting life developed from forces produced by the collision and explosion of celestial bodies.

Divine Creation Theory

The theory that a divine being created the universe and all living organisms based on religious beliefs.

Spontaneous Generation (Abiogenesis)

The idea that living organisms originated from non-living matter.

Biogenesis

The theory explaining that life can only come from pre-existing living organisms.

Chemical Evolution Theory

The theory that life began through chemical reactions where inorganic substances formed organic molecules like amino acids, peptides, and proteins.

Theurgical Theory of Disease

The belief that diseases are caused by the anger of divine spirits as punishment for human sins.

Miasmatic Theory of Disease

The theory that diseases come from harmful vapors or environmental factors and are associated with an imbalance in the body's four humors.

Pore Theory

The idea that disease occurs due to abnormal size or arrangement of body pores.

Germ Theory

The theory explaining that diseases are caused by microorganisms (germs).

Microscopy

The science of investigating small objects using an instrument called a microscope.

Max Knoll and Ernst Ruska

Developed the first electron microscope (TEM) in $1931$, which uses a beam of electrons to examine specimens.

Ocular Lens

The eyepiece of a microscope that usually magnifies the image $10 \times$.

Objective Lenses

Lenses on the rotating nosepiece providing different magnifications: $4 \times$, $10 \times$, $40 \times$, and $100 \times$.

Condenser

The part of a microscope that focuses and directs light onto the specimen.

Magnification

The process of making an object appear larger, with a maximum limit of approximately $2000 \times$ for light microscopes.

Total Magnification Formula

$$\text{Total magnification} = \text{ocular lens} \times \text{objective lens}$$

Resolution

The ability to see two close objects as separate.

Pathogens

Harmful microorganisms that enter the body and cause infection.

Flora

Helpful microbes in the intestines that aid in digestion by breaking down food.

Binomial Nomenclature

A two-part naming system developed by Carl Linnaeus in $1735$ consisting of a Genus and a specific epithet.

Peptidoglycan

The molecular structure of eubacteria cell walls consisting of N-acetylglucosamine, N-acetylmuramic acid, tetrapeptide, side chain, and murein.

Archaea

Prokaryotes that do not have peptidoglycan cell walls.

Three-Domain System

A classification system developed by Carl Woese in $1978$ that groups organisms into Eubacteria, Archaea, and Eukarya.