Microbiology - Intro Flashcards

Microbiology Test 1 - Flashcards - Group 3

Microorganism

A living organism that is too small to be seen with the unaided human eye.

Anabolic Reactions

Metabolic reactions that build large, complex molecules from smaller, simpler parts.

Catabolic Reactions

Metabolic reactions that break down complex molecules into simpler ones, releasing energy (e.g., cellular respiration).

Cellular Respiration

A catabolic process involving $4$ metabolic pathways (Glycolysis, synthesis of acetyl-CoA, Krebs cycle, and Electron Transport Chain) yielding a net total of $36\text{ ATP}$ molecules.

Fermentation

An anaerobic metabolic process that generates ATP without oxygen, producing a net yield of $2\text{ ATP}$ molecules per glucose molecule.

Microbial Growth

An exponential increase in the total number of microbial cells/reproduction rather than an increase in individual cell size.

Generation Time

The doubling time required for a microbial population to reproduce and double in cell number, defined by the formula $N_{\text{final}} = N_{\text{initial}} \times 2^n$.

Bacterial Colony

An aggregation of microbial cells that stemmed from a single parent cell.

Bacterial Growth Curve

A graphic representation of bacterial growth over time, divided into lag phase, exponential (log) phase, stationary phase, and death phase.

Lag Phase

The initial period on a bacterial growth curve where cells prepare for growth but do not yet divide.

Exponential Phase

The phase of rapid cell division and growth on a bacterial growth curve, also known as the log phase.

Stationary Phase

The phase on a bacterial growth curve where the rate of new cell production equals the rate of cell death.

Death Phase

The final phase of a bacterial growth curve where cells die at an exponential rate.

Catalase

An enzyme present in aerobic organisms that splits hydrogen peroxide into water and oxygen.

Peroxidase

An enzyme present in aerobic organisms that breaks down hydrogen peroxide using a reducing agent.

Glycocalyx

An additional outer layer (such as a slime layer) composed of glycoproteins outside the bacterial cell wall that helps prevent drying out in halophilic conditions.

Obligate Aerobes

Organisms that strictly require oxygen to undergo metabolism and survive.

Obligate Anaerobes

Organisms that cannot survive in the presence of oxygen and are killed by it.

Facultative Anaerobes

Organisms that can metabolize and grow with oxygen or switch to anaerobic pathways in its absence (e.g., yeasts and enteric bacteria).

Microaerophiles

Organisms that require oxygen for growth, but at concentrations lower than normal atmospheric oxygen levels.

Aerotolerant Anaerobes

Organisms that do not utilize oxygen for metabolism, but are unaffected by its presence.

Neutrophiles

Organisms, including most bacteria and protozoa, that grow best in neutral pH environments ranging from $6.5\text{--}7.5$.

Acidophiles

Organisms, including most fungi and certain bacteria, that grow optimally in acidic environments.

Alkaliphiles

Organisms that thrive in alkaline environments with an optimal pH of approximately $10$.

Obligate Halophiles

Organisms requiring high salt environments (up to $300\text{g/L}$ or $300\text{g/kg}$ / $30\text{\%}$ salt) that die in freshwater.

Facultative Halophiles

Organisms that do not require high salt concentrations to survive, but are able to tolerate high salt environments.

Thermal Classification of Microorganisms

The grouping of microbes based on growth temperatures: psychrophiles ($-10\text{--}20\text{ }^\text{o}\text{C}$), mesophiles ($10\text{--}45\text{ }^\text{o}\text{C}$), thermophiles ($40\text{--}80\text{ }^\text{o}\text{C}$), and hyperthermophiles ($65\text{--}105\text{ }^\text{o}\text{C}$).

Bacteria

Unicellular prokaryotic organisms that typically possess peptidoglycan cell walls and exist in shapes such as bacillus, coccus, and spiral.

Archaea

Unicellular prokaryotic organisms whose cell walls lack peptidoglycan; includes methanogens, halophiles, and extreme thermophiles.

Fungi

Eukaryotic organisms that are usually multicellular and reproduce sexually or asexually.

Algae

Unicellular or multicellular photosynthetic protists that generate oxygen and carbohydrates utilized by other organisms.

Protozoa

Unicellular eukaryotic protists that absorb or ingest nutrients and can move using pseudopods, flagella, or cilia.

Viruses

Acellular parasitic entities consisting of nucleic acid inside a protein coat (and sometimes an envelope) that replicate only within a host cell.

Helminths

Multicellular animal parasites, specifically flatworms and roundworms, identified in microbiological procedures via microscopic life cycle stages.

Spontaneous Generation

The historical belief that living organisms could arise spontaneously from non-living matter.

Biogenesis

The concept, popularized by Rudolf Virchow, that living cells arise only from pre-existing living cells.

Golden Age of Microbiology

The period from $1857\text{--}1914$ characterized by rapid advancements in germ theory, vaccinations, culturing techniques, and immunology.

Germ Theory of Disease

The principle that microorganisms can invade other organisms and cause infectious diseases.

Pasteurization

The process of heating food or liquid for a specific time to destroy harmful microbes without spoiling the product.

Normal Flora

Microorganisms naturally residing in and on the human body that typically maintain a mutualistic relationship with the host.

Nosocomial Infection

An infection acquired by a patient during a stay or procedure in a healthcare facility.

Lactic Acid Fermentation

A metabolic pathway converting pyruvic acid into lactic acid, carried out by bacteria, fungi, and animal cells.

Alcoholic Fermentation

A metabolic pathway converting pyruvic acid into ethyl alcohol and carbon dioxide, carried out by yeasts and plants.

Robert Hooke

Scientist who observed cell structures using an improved compound microscope and coined the term 'cell'.

Antonie van Leeuwenhoek

Pioneer known as the father of microbiology who first observed living microorganisms using a single-lens microscope.

Francesco Redi

Scientist who challenged spontaneous generation by showing maggots arose from fly eggs on meat rather than the meat itself.

John Needham

Scientist who argued in favor of spontaneous generation after observing microbial growth in boiled broths.

Lazzaro Spallanzani

Scientist who refuted Needham's claims by heating broth in sealed flasks, showing no microbial growth occurred without air entry.

Louis Pasteur

Scientist who disproved spontaneous generation using S-necked flasks, showed microbes are present in the air, and developed pasteurization.

Robert Koch

Scientist who formulated Koch's postulates to establish specific microorganisms as the causative agents of specific diseases.

Edward Jenner

Scientist who developed the first smallpox vaccine by inoculating individuals with the cowpox virus.

Alexander Fleming

Scientist who discovered the antibiotic penicillin produced by the fungus Penicillium.