Prokaryotes and the Origins of Metabolic Diversity

These flashcards cover key concepts about prokaryotes, their structure, metabolism, symbiosis, and ecological impacts.

Prokaryotes

Single-celled organisms that lack a nucleus and membrane-bound organelles.

Domain Bacteria

The majority of prokaryotes, characterized by cell walls that contain peptidoglycan.

Peptidoglycan

A polymer consisting of sugars and amino acids that forms a mesh-like layer outside the plasma membrane of bacteria.

Domain Archaea

Prokaryotes that lack peptidoglycan in their cell walls and possess unique lipids in their plasma membranes.

Methanogens

Archaea that produce methane by reducing CO2 in anaerobic conditions.

Extreme halophiles

Organisms that thrive in high-salinity environments, using pigments like bacteriorhodopsin for light absorption.

Extreme thermophiles

Organisms that grow at very high temperatures, often found in geothermal locations.

Bioremediation

The process of using organisms, like bacteria, to remove or neutralize contaminants from an environment.

Cyanobacteria

Photosynthetic bacteria that can produce oxygen as a byproduct and played a crucial role in the oxygen revolution.

Nitrogen fixation

The conversion of atmospheric nitrogen (N2) into a form usable by organisms, primarily carried out by cyanobacteria and some archaea.

Photoautotrophs

Organisms that synthesize organic compounds from CO2 using light energy.

Chemotrophs

Organisms that obtain energy from chemical sources found in their environment.

Autotrophs

Organisms that utilize CO2 as a primary carbon source to produce organic molecules.

Heterotrophs

Organisms that require at least one organic nutrient as a carbon source for growth.

Saprobes

Decomposers that absorb nutrients from dead organic matter.

Obligate aerobes

Prokaryotes that require oxygen for cellular respiration.

Facultative anaerobes

Prokaryotes that can grow in the presence or absence of oxygen.

Obligate anaerobes

Prokaryotes that are poisoned by oxygen and must use alternative electron acceptors.

cocci

spherical

diplococci

paired

streptococci

chains

staphylococci

bunch of grapes

bacilli

rod shaped

spirilla

helical

spirochetes

corkscrew

Transformation

process by which external DNA is incorporated by bacterial cells

Conjugation

direct transfer of genes from one bacterium to another

Transduction

transfer of genes between bacteria by viruses (bacteriophages)