Bacterial Cells, Plasmids, and Motility (Video Notes)

Vocabulary flashcards covering key terms about bacterial cell structure, plasmids, and bacterial motility as described in the video notes.

Bacteria

A domain of prokaryotic organisms with simple cell organization; typically have a circular chromosome in a nucleoid and may carry plasmids.

Archaea

A separate domain of prokaryotes distinct from bacteria, with differences in membrane lipids and genetics.

Bacillus

Rod-shaped (rod-like) bacterium.

Coccus

Spherical (round) bacterium.

Spirillum

Spiral-shaped bacterium.

Nucleoid

Region in a bacterial cell where the main circular chromosome is located, not enclosed by a membrane.

Plasmid

Small, circular DNA molecule that is self-replicating and carries extra genes; can be transferred between bacteria.

Chromosome

Main genetic material in bacteria; typically a single circular chromosome located in the nucleoid.

R plasmid

A plasmid carrying genes that confer resistance to antibiotics, aiding survival in the presence of antibiotics.

Efflux pump

Protein that pumps antibiotics out of the cell, contributing to antibiotic resistance.

Antibiotic-degrading enzyme

Enzyme that degrades antibiotics, reducing their effectiveness.

Antibiotic-modifying enzyme

Enzyme that chemically alters an antibiotic to inactivate it.

Col plasmid

Colicin-producing plasmid found in coliform bacteria; encodes proteins that kill related bacterial strains.

Bacteriocins

Antimicrobial compounds produced by bacteria that inhibit or kill closely related bacteria.

F plasmid

Fertility plasmid that enables DNA transfer via conjugation by encoding transfer machinery.

Sex pilus

A pilus used to connect donor and recipient bacteria during conjugation for DNA transfer.

Conjugation

Transfer of genetic material between bacteria through the sex pilus; not the production of a new organism.

T plasmid

Toxin plasmid carrying genes that enable production of toxins affecting a host.

Toxin

Protein produced by bacteria that can damage host tissues or interfere with host biology.

Coliform bacteria

Group of Gram-negative, lactose-fermenting bacteria (e.g., E. coli) used in studying plasmids.

Flagellum

Rotating, whip-like appendage that provides bacterial motility; composed of flagellin subunits.

Flagellin

Protein subunits that polymerize to form the bacterial flagellum.

Motility

Ability of bacteria to move; often achieved by flagella.

Run and tumble

Movement pattern where runs (forward motion) are interspersed with tumbles (reorientation); driven by rotation of the flagellum.

Chemotaxis

Directed movement toward a positive stimulus (e.g., nutrients) or away from a negative one.

Fimbriae

Short, numerous appendages that help bacteria attach to surfaces.

Gram-positive

Bacteria with a thick peptidoglycan cell wall and no outer membrane; stains purple in Gram staining.

Peptidoglycan

Rigid polymer forming the bacterial cell wall; thickness varies between Gram-positive and Gram-negative.

Ribosome

Molecular complex responsible for protein synthesis; bacteria have 70S ribosomes.

Cytoplasm

Internal, aqueous content of the cell where metabolism and growth occur (contains ribosomes and other components).

monotrichous

one flagellum

amphitricous

flagella on both ends

lophotricous

tuft of flagellalocated at one end of the cell

peritrichous

flagella surrounding cell