Eubacteria and Prokaryotes Vocabulary

Classification of Eubacteria

Classified by shape, configuration, respiration, and nutrition.

Bacterial Shapes

• Cocci (spherical): These bacteria can be found in various arrangements, including clusters and chains, greatly influencing their classification and interaction with hosts.
• Bacilli (rod-shaped): Often associated with different diseases and environmental roles, can occur singly or in pairs.
• Spirilla/Spirochetes (spiral): Characterized by their corkscrew motion which aids in mobility through viscous environments like mucus.

Bacterial Configurations

• Pairs: (diplococci, diplobacilli)
• Clusters: (staphylococci)
• Chains: (streptococci, streptobacilli)
• Others: Sarcina (cubical arrangement), Tetrad (groups of four), Palisades (side-by-side arrangement)

Bacteria Characteristics

• Unicellular: Although primarily unicellular, certain bacteria may exist in temporary colonies for cooperative behavior.
• Prokaryotic: Eubacteria lack a nucleus and membrane-bound organelles, making them fundamentally different from eukaryotes.
• Single chromosome: Typically composed of a single circular DNA loop or additional plasmids that can carry advantageous traits.
• Asexual reproduction: Primarily through binary fission, allowing rapid population growth, especially in favorable conditions.
• Moist environments: Most eubacteria thrive in environments with sufficient moisture as they rely on water for metabolic functions.

Classification of Prokaryotes

• Two kingdoms: Archaebacteria and Eubacteria, showcasing significant differences in genetics and cellular structures.

Archaebacteria

• Thrive in extreme environments: Display unique adaptations that allow survival in conditions inhospitable to other forms of life, such as high temperature or salinity.
  • Thermophiles: These organisms flourish in hot temperatures, such as hot springs.
  • Halophiles: Adapted to high saline environments, found in salt lakes and evaporation ponds.
  • Methanogens: Methane-producing organisms that can survive in environments devoid of oxygen, like swamps and the digestive systems of ruminants.
• No peptidoglycan in cell walls: The cell walls of Archaebacteria lack peptidoglycan, differing from Eubacteria.

Eubacteria

• All other bacteria: Represent the majority of bacterial species and exhibit diverse metabolic pathways.
• Peptidoglycan in cell walls: Provides structural support and is the target of certain antibiotics.
• Can be helpful or harmful: Some eubacteria are beneficial (e.g., E. coli aiding digestion), while others act as pathogens causing diseases.

Respiration Types

• Obligate Aerobe: Requires oxygen for growth and energy production.
• Obligate Anaerobe: Cannot survive in the presence of oxygen; oxygen is toxic to these organisms.
• Facultative Anaerobe: Capable of switching between aerobic and anaerobic respiration, allowing resilience in varying environments.

Nutrition Types

• Photoautotrophs: Utilize light energy and CO_2 as a carbon source, playing a critical role in ecosystems.
• Photoheterotrophs: Depend on light energy but require organic compounds for carbon, found in diverse environments such as coastal regions.
• Chemoautotrophs: Obtain energy from inorganic compounds and use CO_2 for carbon dioxide, often found in deep-sea vents.
• Chemoheterotrophs: Require organic compounds for both energy and carbon sources, a common strategy among eubacteria.

Bacterial Cell Structure

• Includes components such as plasmids for genetic variation, flagella for movement, and pili for adhesion and horizontal gene transfer.
• Do not possess a nucleus or membrane-bound organelles, contrasting sharply with eukaryotic cells that have distinct organelles.
• Contains ribosomes important for protein synthesis and a semi-fluid cytoplasm that aids metabolic processes.

Conjugation

• Process of genetic material transfer via pilus between donor and recipient cells, increasing genetic diversity and adaptability of bacteria.

Antibiotic Resistance (AMR)

• Germs (bacteria, fungi) develop the ability to defeat drugs designed to kill them, presenting a significant challenge in medical treatment.
• Mechanisms: Can include avoiding antibiotic targets, changing or destroying antibiotics