Microbiology Lecture Notes Practice Flashcards

Flashcards covering key microbiology lecture topics including microbial classification, cell structures, major historical milestones, Koch's postulates, and industrial/agricultural applications.

What term is used to describe microorganisms that cause infectious diseases?

Pathogens (or pathogenic microorganisms)

Which two groups of microbes are classified as prokaryotes?

Bacteria and Archaea

Which three groups of microbes are classified as eukaryotes?

Algae, Fungi, and Protozoa

What are the structural characteristics and size range of prokaryotic cells?

They have a super simple cellular structure with no true nucleus and no membrane-bound organelles, range from $0.1{-}5\,\mu m$ in size, contain DNA, ribosomes, cell membrane, and cytoplasm, and reproduce asexually.

What are the structural characteristics and size range of eukaryotic cells?

They have a complex cellular structure containing a true nucleus and membrane-bound organelles, range from $10{-}100\,\mu m$ in size, can be unicellular or multicellular, and reproduce sexually or asexually.

What component composes bacterial cell walls and determines their shape?

Peptidoglycan

What are the three basic shapes of bacteria?

Rod-shaped, spherical-shaped, and spiral-shaped.

By what process do bacteria reproduce?

Binary fission

What are the three ways bacteria can obtain energy or nutrients?

1. Photosynthesis (e.g., cyanobacteria), 2. Consuming organic molecules (containing Carbon), and 3. Consuming inorganic molecules (containing Nitrogen and/or Phosphorus).

How do the cell walls of Archaea differ from those of bacteria?

Archaea cell walls lack peptidoglycan.

Are Archaea pathogenic to humans?

No, Archaea are not pathogenic to humans.

What are the three types of Archaea and their environmental habitats?

Methanogens (live in anaerobic habitats and produce methane), Thermophiles (live in extremely hot environments), and Halophiles (live in extremely salty environments).

What material composes the cell walls of Algae?

Cellulose

What material composes the cell walls of Fungi?

Chitin

How do fungi obtain energy since they are non-photosynthetic?

They obtain energy by feeding off the organic decomposition of dead organisms.

What are the three types of fungi described in the lecture notes?

Mushrooms (multicellular, produce microscopic infectious spores), Yeast (unicellular), and Mold (multicellular, composed of long filaments that form colonies).

What three structures can Protozoa use for locomotion?

Cilia, flagella, or pseudopodia ("fake feet").

Which protozoan genus is an exception for being photosynthetic?

Genus Euglena

Why are viruses considered acellular, and how can they be visualized?

Viruses are not made of cells (referred to as viral particles) and cannot be seen with a regular light microscope; they can only be seen with an electron microscope.

What type of genetic material is contained in the core of a virus?

Either DNA or RNA (not both), surrounded by a protein coat.

What are the two subtypes of Helminths and examples of each?

Flatworms (subtypes Cestoda and Trematoda; e.g., tapeworms in intestines from raw meat) and Roundworms (subtypes Ascarids, Pinworms; e.g., hookworms from walking barefoot).

According to the Binomial System of Nomenclature, how is a scientific name written?

The Genus name is capitalized, the species name is not capitalized, and both names are italicized or underlined.

Who was the first person to observe living microorganisms?

Antonie van Leeuwenhoek

What is spontaneous generation, and who disproved it?

Spontaneous generation was the incorrect 1600s belief that nonliving things can generate living things; it was disproved by Louis Pasteur, who proved microorganisms only originate from pre-existing live microorganisms.

What is pasteurization and who invented it?

Invented by Louis Pasteur, pasteurization is a mild heating process that inhibits the growth of bacteria causing spoilage and kills potential human pathogens to elongate shelf life.

What is the Germ Theory of Disease, and who developed it?

Developed by Robert Koch, it is the concept that specific infectious diseases are caused by specific microorganisms.

Which specific bacterium and disease were used to prove the Germ Theory of Disease?

Bacillus anthracis, which causes Anthrax.

What are Koch's 4 Postulates in sequential order?

1. The suspected microorganism must be present in every sick person and absent from healthy people. 2. Isolate and grow the suspected microorganism in a laboratory culture. 3. Introduce the cultured microorganism into a healthy experimental animal, which must develop the same disease/symptoms. 4. Re-isolate the microorganism from the newly sick animal, confirming it is the same original microorganism.

Who created the first vaccine, in what year, and for what disease?

Edward Jenner created the smallpox vaccine in $1796$ by exposing a child to cowpox blister material to trigger immunity.

Who discovered Penicillin, in what year, and from what microorganism?

Alexander Fleming discovered Penicillin by accident in $1929$ when a mold of the genus Penicillium produced an inhibitory chemical that prevented the growth of Staphylococcus aureus.

Which bacterial genus produces most of the natural antibiotics used today?

Genus Streptomyces

What occurs during lactic acid fermentation by lactic acid bacteria?

Lactic acid bacteria ferment sugar in the absence of oxygen to produce lactic acid, creating an acidic environment that inhibits bacterial growth and contributes a sour taste.

What process occurs during alcoholic fermentation by yeast?

Yeast metabolizes sugar without oxygen to produce ethanol and $CO_2$.

What is mineralization in agricultural microbiology?

The process by which microorganisms (usually bacteria) convert organic nutrients into inorganic nutrients to improve soil fertility.

How are bacteria from the Genus Bacillus used in agriculture?

They are used as bioinsecticides because they are natural insect pathogens that only harm insects.

How do beneficial microorganisms assist in sewage treatment and water recycling?

They oxidize biodegradable organic matter in sewage, breaking it down with oxygen into safe water and $CO_2$.