BIO201 Prokaryotes, Eukaryotes, and Endosymbiosis Flashcards

Vocabulary flashcards covering core terms related to prokaryotes, eukaryotes, endosymbiosis, and key cycles and structures from the notes.

Prokaryotes

Organisms whose cells lack a nucleus; include Bacteria and Archaea; typically unicellular with circular DNA.

Eukaryotes

Organisms whose cells have a nucleus and membrane-bound organelles; can be single- or multi-celled.

Archaea

A domain of prokaryotes with unique membrane lipids and no peptidoglycan; many extremophiles.

Bacteria

A domain of prokaryotes with peptidoglycan in cell walls; diverse morphologies and metabolisms.

Peptidoglycan

A polymer that forms a rigid cell wall in most bacteria.

Gram-positive

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

Gram-negative

Bacteria with a thin peptidoglycan layer and an outer membrane; stains pink in Gram stain.

Archaea membrane lipids

Archaeal lipids are branched and ether-linked, unlike the ester-linked lipids of bacteria and eukaryotes.

Mitochondrion

Eukaryotic organelle for aerobic respiration; contains its own circular DNA and ribosomes; double membrane.

Chloroplast

Plant/algae organelle for photosynthesis; likely originated from cyanobacteria; has its own DNA.

Endosymbiosis

Evolutionary theory that organelles like mitochondria and chloroplasts originated as symbiotic bacteria.

Endosymbiotic theory

Proposal that eukaryotic organelles arose from engulfed prokaryotes; supported by multiple bacterial traits in organelles.

Cyanobacteria

Photosynthetic prokaryotes capable of oxygenic photosynthesis; major early source of atmospheric O2.

Oxygen Revolution

Rise of atmospheric oxygen due to cyanobacteria, enabling aerobic respiration and the evolution of eukaryotes.

Nitrogen cycle

Biogeochemical cycling of nitrogen through fixation, ammonification, nitrification, and denitrification.

Nitrogen-fixing bacteria

Bacteria that convert atmospheric N2 into ammonia/NH4+; often live in root nodules of legumes.

Anabaena

Genus of cyanobacteria that can fix nitrogen in specialized cells called heterocysts.

Mycoplasma

Very small bacteria lacking a cell wall.

Endospores

Durable, dormant structures formed by some Gram-positive bacteria to survive harsh conditions.

Capsule

A protective outer layer around some bacteria that aids in protection and adherence.

Fimbriae

Hair-like appendages used by bacteria for attachment to surfaces.

Biofilm

A structured community of microorganisms embedded in a matrix on a surface.

Flagella

Motility machinery in bacteria; structurally different and smaller than eukaryotic flagella.

Conjugation

DNA transfer between bacteria through direct cell-to-cell contact.

Transformation

Uptake of free DNA from the environment by bacteria.

Transduction

DNA transfer between bacteria mediated by bacteriophages.

Nucleoid

Region in a prokaryotic cell where the chromosome is located; not enclosed by a membrane.

Operon

A cluster of functionally related genes under a single promoter in prokaryotes.

Methionine

Amino acid that initiates protein synthesis in eukaryotes.

Formylmethionine (fMet)

First amino acid incorporated at the start of bacterial protein synthesis.

Extremophile

Organism, often an archaeon, thriving in extreme environmental conditions.