BIOL120 - Introduction to Microbiology, Chemistry, and Prokaryotes

Flashcards covering the history of microbiology, basic chemistry, macromolecule structures, and the anatomy and growth patterns of prokaryotic cells.

What is the scientific method?

A systematic process for studying natural phenomena that involves asking questions, proposing a hypothesis, gathering information, evaluating results, and communicating findings.

Who was Antonie van Leeuwenhoek and what was his contribution to microbiology?

A Dutch draper in the late 1600s who invented one of the first effective microscopes and discovered an invisible world of microorganisms he called 'animalcules'.

What is spontaneous generation?

An early explanation for the origins of small organisms which suggested they could arise from non-living or rotting material under the right conditions.

How did Francesco Redi's experiment challenge spontaneous generation?

He showed that if meat was protected with a mesh barrier, maggots did not appear because flies could not come into contact with the meat.

How did Louis Pasteur's swan-necked flask experiment disprove spontaneous generation for microbes?

The flask allowed air to pass through but trapped dust-containing microbes in the bend of the neck, preventing broth contamination without needing to seal out oxygen.

Who discovered the first vaccine and for which disease?

Edward Jenner, who used cowpox to inoculate a boy against smallpox after observing that milkmaids who caught cowpox were immune to smallpox.

What contributions did Oliver Wendell Holmes and Ignaz Semmelweis make to medical hygiene?

They identified that childbed fever was being transferred between patients; Semmelweis specifically instituted handwashing protocols to reduce mortality rates.

Who pioneered the use of carbolic acid as an antiseptic in surgery?

Joseph Lister.

What is the Germ Theory of Disease?

The theory that microorganisms invade the human body and cause disease, a concept developed through the work of Louis Pasteur and others.

What are Koch’s Postulates?

A series of testing steps used to determine the specific organism responsible for a disease, requiring the organism to be present in all cases, isolated in pure culture, and capable of causing disease in a healthy individual.

What contribution did Ferdinand Cohn make to microbiology?

He recognized that some bacterial species could form endospores, which are highly resistant structures that cannot be destroyed by simple boiling.

Who discovered penicillin and how was it discovered?

Alexander Fleming discovered it accidentally when he returned from vacation to find that a mold contaminant on his agar plates was inhibiting the growth of bacteria.

What are the three components of an atom?

Protons (positive charge), Electrons (negative charge), and Neutrons (no charge).

What is the difference between a covalent bond and an ionic bond?

Covalent bonds occur when atoms share electrons, while ionic bonds result from the attraction between ions with opposite charges.

What are the four types of macromolecules vital to all organisms?

Carbohydrates, lipids, proteins, and nucleic acids.

What are the structural components of a phospholipid?

A triglyceride where one fatty acid is replaced by a negatively charged, polar phosphate head group, creating a molecule with a hydrophilic head and hydrophobic tails.

What are the four levels of protein structure?

Primary (sequence of amino acids), Secondary (helices or sheets), Tertiary (3D shape), and Quaternary (multiple 3D subunits clustered together).

What is the difference between DNA and RNA sugars?

DNA contains deoxyribose, while RNA contains ribose.

What is adenosine triphosphate (ATP)?

A nucleotide used to store energy; energy is released when the bond holding the third phosphate is broken, turning $ATP$ into $ADP$.

What are the three common shapes of bacteria?

Cocci (round), bacilli (rod-shaped), and spirillum (spiral-shaped).

What is binomial nomenclature?

A naming system for organisms using two levels of classification: the Genus (capitalized) and the species (lowercase), both of which are italicized or underlined.

What is the difference between monotrichous and peritrichous flagella arrangements?

Monotrichous refers to a single flagellum at one end, while peritrichous refers to flagella randomly spread over the entire surface of the cell.

What is chemotaxis?

The movement of bacteria in response to chemical signals, characterized by a 'random walk' or zig-zag motion to follow concentration gradients.

What is the difference between a slime layer and a capsule in the glycocalyx?

A slime layer is loosely constructed, while a capsule is a more structured, organized, and dense layer that often contributes to bacterial virulence.

How do Gram-positive and Gram-negative cell walls differ?

Gram-positive cells have a thick layer of peptidoglycan, while Gram-negative cells have a thin layer of peptidoglycan and an outer membrane containing lipopolysaccharide (LPS).

What is an endotoxin?

Lipopolysaccharide (LPS) found in the outer membrane of Gram-negative bacteria that is released when the cell is destroyed, potentially causing serious complications in blood infections.

What is a plasmid?

Small, circular DNA molecules in the cytoplasm that contain genes independent of the main chromosome, often carrying genes for antibiotic resistance or special metabolism.

What is the function of a bacterial endospore?

It is a dormant, non-reproductive structure that allows a cell to survive extreme conditions like high heat ($121^{\circ}\text{C}$), radiation, and chemicals for long periods.

By what process do bacteria reproduce?

Binary fission, which is a form of asexual reproduction where one cell becomes two identical cells.

What are the four phases of the bacterial growth curve in a closed system?

Lag phase (preparation), Exponential growth phase (maximum division), Stationary phase (birth rate equals death rate), and Death phase (nutrients depleted, waste accumulated).

How many generations are required for a single bacterial cell to reach a population of one million?

Approximately $20$ generations ($2^{20} \approx 1,048,576$).