Microbiology Midterm Review: Pathogens, Evolution, and Nutrient Acquisition

Vocabulary flashcards covering microbial communication, evolution, antibiotic resistance, symbiotic relationships, and nutrient acquisition based on the lecture transcript.

Quorum sensing

The process by which bacteria detect a threshold of population density using secreted proteins to coordinate the release of virulence factors.

Virulence factors

Molecules or traits produced by bacteria that enable them to colonize a host, evade the immune system, and cause disease.

Toxic shock syndrome

A condition resulting from a high number of bacteria (such as those in the vaginal tract) attaching to a substrate like a tampon and releasing virulence factors.

Polymicrobial

A term describing biofilms or infections that consist of more than one type of microbe, making them difficult to treat with a single antibiotic.

Nosocomial

A term for a hospital-acquired infection that occurs because of clinical procedures or the hospital environment.

Conjugation

A mechanism of genetic transfer where a plasmid is passed from one gram-negative cell to another via a pilus, often spreading antibiotic resistance genes.

Plasmid

A circular structure of genetic information that can be transferred between bacteria.

Binary fission

A form of rapid asexual reproduction in bacteria where one cell divides into two, leading to exponential population growth ($2, 4, 8, 16, 32, 64...$).

Selective pressure

Environmental factors, such as the presence of antibiotics or diseases like malaria, that allow specific beneficial mutations to be retained in a population while others die off.

C. difficile (C. diff)

An endospore-forming bacteria in the intestine that can cause diarrhea when antibiotics wipe out normal flora, removing competition and allowing it to proliferate.

Opportunistic infection

An infection that takes advantage of an opportunity not normally available, such as a host with a weakened immune system or a disrupted microbiome.

Mutualistic relationship

A symbiotic relationship in which both the microbe and the host benefit from the interaction.

Commensal relationship

A relationship where a microbe lives on or in a host without causing harm, but the host receives no significant benefit.

Parasite

An organism that lives in or on a host and causes harm while benefiting from the relationship.

Synergism

A non-symbiotic relationship where free-living organisms cooperate and share nutrients to grow better together, such as orchids thriving with certain fungi.

Antagonism

A relationship between free-living organisms where they compete and cause harm to one another, such as Penicillium mold secreting penicillin to kill bacteria.

Heterotroph

An organism that must acquire carbon in organic form by eating other animals or plants.

Autotroph

An organism that acquires carbon from inorganic sources, specifically $CO_2$.

Chemotroph

An organism that gains its energy from chemical compounds.

Phototroph

An organism that obtains its energy from light via photosynthesis.

Chemoheterotroph

Organisms, including humans and all mammals, that degrade large organic molecules to obtain both carbon and energy.

Solute

The substance that is dissolved in a solvent to form a solution, such as glucose, salt, or potassium.

Solvent

The dissolving medium in a solution; water is considered the universal solvent.

Osmosis

The passive movement of water across a membrane from an area of high water concentration to an area of low water concentration.

Hypertonic

A solution state characterized by having a higher concentration of solute compared to another solution.

Hypotonic

A solution state characterized by having a lower concentration of solute compared to another solution.

Isotonic

A condition where two solutions have an equal concentration of solutes.