Microbiology Lecture Flashcards

Flashcards covering microbiology concepts including bacterial structure, pathogens, metabolism, genetics, and domain characteristics.

Prokaryotes

Organisms that have no true nucleus ($Pro$ = NO; $Kary$ = true).

Gram-Positive

Bacteria characterized by a thick peptidoglycan cell wall and the presence of lipoteichoic acid.

Gram-Negative

Bacteria with a thin peptidoglycan layer, an outer lipid membrane, and lipopolysaccharides ($LPS$).

Spirochete

A bacterium with a corkscrew shape, such as $Borrelia$ $burgdorferi$.

Granuloma

The hallmark pathology of Tuberculosis ($TB$) where macrophages and T cells wall off an infection or foreign object.

Acid-Fast

A characteristic of $Mycobacterium$ due to a waxy layer that makes them unable to be stained by traditional methods.

Opportunistic Pathogen

A microbe that typically does not cause disease unless the host is immunocompromised, such as $Pseudomonas$ $aeruginosa$.

Exopolysaccharide

Structures on the outside of many bacteria, such as $psl$, $pel$, and $alginate$, that help form biofilms and protect against desiccation.

Biofilm

A collection of cells in a self-produced matrix that helps microbes prevent drying and provides resistance to toxins and predators.

Spores

A dormant state formed by bacteria like $Bacillus$ and $Clostridium$ that is resistant to heat, desiccation, and disinfectants.

Archaea

A domain of life often found in harsh environments characterized by cell membranes with ether linkages and branched hydrocarbons.

Planktonic

Free-floating bacterial cells that do not express the genes required to form exopolysaccharides.

Peptidoglycan

An alternating copolymer of $\beta(1-4)$-N-acetyl-D-glucosamine and N-acetylmuramic acid that provides structural support to bacterial cell walls.

Dysbiosis

An imbalance in the relationship between the host's epithelial cells and the microbiota.

Zoonotic

Pathogens or diseases that reside in animal populations and can be transmitted to humans.

Substrate-level Phosphorylation

A method of making $ATP$ involving the direct transfer of a $PO_4$ group from one molecule to another.

Oxidative Phosphorylation

The generation of $ATP$ via the Electron Transport Chain ($ETC$) using a series of redox reactions.

Glycolysis

The process occurring in the cytoplasm that breaks down a $6C$ sugar into two molecules of pyruvate, yielding a net of $2$ $ATP$ and $2$ $NADH$ molecules.

Quorum Sensing

Chemical communication between bacteria using signaling molecules like Acyl-homoserine lactones ($AHLs$) to coordinate population activities.

Semiconservative Replication

The process of copying $DNA$ where each resulting double-stranded molecule contains one original strand and one newly synthesized strand.

Horizontal Gene Transfer

The movement of genetic material between bacteria through transformation, transduction, or conjugation.

Transformation

The process where a bacterium takes up naked $DNA$ from its environment.

Transduction

The transfer of genetic material from one bacterium to another by a virus or bacteriophage.

Conjugation

A process of exchanging $DNA$ between bacterial cells involving the use of a pilus.

Operon

A group of genes in prokaryotes organized together with a single regulatory sequence or promoter, such as the $lac$ operon.

Codon

A sequence of three nucleotides in $mRNA$ that corresponds to a specific amino acid during translation.

Prophage

Viral nucleic acid that has been inserted into a bacterial genome during the lysogenic cycle.

Capsule

An anti-phagocytic structure that prevents bacterial cells like $Streptococcus$ $pneumoniae$ from being engulfed by the immune system.

Lipid Rafts

Rigid areas of the cell membrane containing high levels of cholesterol and sphingolipids that help organize protein interactions.