Chapter 26 Bacteria and Archaea

Bacteria

Unicellular prokaryotes lacking membrane-bound nucleus.

Archaea

Prokaryotes with distinct plasma membranes and cell walls.

Prokaryotes

Organisms without a membrane-bound nucleus.

Microbiome

Community of microbes inhabiting a specific area.

Extremophiles

Prokaryotes thriving in extreme environments.

Koch's Postulates

Criteria linking specific microbes to specific diseases.

Germ Theory

Theory stating some diseases are caused by microbes.

Pathogens

Bacteria causing illness in humans.

Bioremediation

Use of microbes to clean up environmental contaminants.

Habitat Diversity

Variety of environments where bacteria and archaea thrive.

Marine Archaea

Over 10,000 individuals per mL in seawater.

Microbiology

Study of microbes including bacteria and archaea.

Antibiotics

Substances that inhibit bacterial ribosome function.

Human Microbiome

Microbes residing on and within the human body.

Fossil Record

Oldest fossils are 3.5 billion years old.

Eukarya

Third major domain of life, includes multicellular organisms.

Hydrothermal Vents

Extreme habitats where some extremophiles are found.

Phytophthora infestans

Pathogen responsible for potato famine.

Infectious Diseases

Diseases spread by microbes through various transmission methods.

Microbial Abundance

Bacteria and archaea dominate total life-form volume.

Enzymes

Proteins used in industrial processes at extreme conditions.

Transmission Methods

Ways infectious diseases spread among hosts.

Virulence

Ability of an organism to cause disease.

Heritable trait

Characteristic that can be passed to offspring.

Pathogenic strains

Bacteria capable of causing disease.

Escherichia coli

Bacteria with both pathogenic and harmless strains.

Virulence genes

Genes that enhance pathogenicity in bacteria.

E. coli O157:H7

Pathogenic strain harmful to humans.

Endospores

Dormant structures formed under environmental stress.

Thick-walled structure

Characteristic of endospores for protection.

Resistant to stressors

Endospores withstand heat, UV, and antibiotics.

Resume growth

Endospores reactivate in favorable conditions.

Antibiotics

Molecules that kill or inhibit bacterial growth.

Natural production

Antibiotics produced by soil bacteria and fungi.

Drug resistance

Bacteria evolve to survive antibiotic treatment.

Biofilms

Bacterial colonies protected by a polysaccharide matrix.

Bioremediation

Use of microbes to clean polluted environments.

Water pollutants

Toxic substances that do not dissolve in water.

Fertilizing contaminated sites

Encouraging growth of bacteria in polluted areas.

Seeding

Adding specific bacteria to enhance bioremediation.

Clostridium difficile

Bacteria known for endospore formation.

Enrichment Cultures

Isolate cells growing under specific laboratory conditions.

Thermophiles

Microbes that thrive in high-temperature environments.

Metagenomics

Environmental sequencing to identify species via DNA.

Prokaryotic Diversity

Variety of prokaryotic organisms in different habitats.

Human Microbiome

Community of microbes inhabiting the human body.

Gut Microbiome

100 trillion bacteria and archaea in the gut.

Symbiotic Prokaryotes

Prokaryotes that benefit human health and function.

Inflammatory Bowel Disease

Condition linked to changes in gut microbiome.

Obesity

Health issue associated with gut microbiome alterations.

Molecular Phylogenetics

Study of evolutionary relationships using molecular data.

16S rRNA

RNA used to study bacterial phylogenetics.

18S rRNA

RNA used to study eukaryotic phylogenetics.

Tree of Life

Phylogenetic tree representing evolutionary relationships.

Carl Woese

Scientist who analyzed rRNA for phylogenetic studies.

Monophyletic Groups

Clades representing a common ancestor in phylogeny.

Clades

Lineages derived from a common ancestor.

Three Domains Hypothesis

Life divided into Bacteria, Archaea, and Eukarya.

Prokaryotes

Single-celled organisms without a nucleus.

Eukaryotes

Organisms with complex cells containing a nucleus.

Morphological Characteristics

Physical traits used in phylogenetic analysis.

Molecular Characteristics

Genetic traits used in phylogenetic analysis.

Genetic Variation

Diversity in genetic traits among organisms.

Gene Transfer

Movement of genetic material between organisms.

Lateral Gene Transfer

Acquisition of traits not via reproduction.

Transformation

DNA uptake from environment by bacteria.

Transduction

DNA transfer via viruses between prokaryotes.

Conjugation

Direct transfer of genetic material between cells.

Plasmid Transfer

Transfer of plasmids during conjugation.

Morphological Diversity

Variation in size, shape, and arrangement of bacteria.

Gram Stain

Dyeing technique to classify bacterial cell walls.

Gram-positive Cells

Bacteria with thick peptidoglycan layers, appear purple.

Gram-negative Cells

Bacteria with thin peptidoglycan, appear pink.

Metabolic Diversity

Variety of metabolic pathways in bacteria and archaea.

Phototrophs

Organisms using light for ATP production.

Chemoorganotrophs

Organisms oxidizing organic molecules for energy.

Chemolithotrophs

Organisms oxidizing inorganic molecules for energy.

Autotrophs

Organisms synthesizing compounds from simple materials.

Heterotrophs

Organisms obtaining compounds from their environment.

Cellular Respiration

Process of generating ATP through electron transport.

Fermentation

ATP production without electron transport chains.

Photophosphorylation

ATP synthesis using light energy.

Oxygenic Photosynthesis

Photosynthesis using water as electron source.

Anoxygenic Photosynthesis

Photosynthesis without producing oxygen.

Nitrogen Fixation

Conversion of atmospheric nitrogen into usable forms.

Nitrogen Cycle

Movement of nitrogen through ecosystems.

Nitrate Pollution

Environmental impact from excess nitrates in water.

Actinobacteria

Filamentous bacteria important for decomposition.

Chlamydiae

Least diverse bacteria, live as parasites.

Cyanobacteria

Photosynthetic bacteria producing oxygen and organic matter.

Firmicutes

Bacteria aiding digestion and causing diseases.

Proteobacteria

Diverse bacteria involved in nitrogen cycling.

Spirochaetes

Corkscrew-shaped bacteria, some are pathogens.

Crenarchaeota

Archaea thriving in extreme environments.

Euryarchaeota

Archaea living in diverse habitats.

Thaumarchaeota

Ancient archaeal lineage abundant in various environments.