Bacterial Structure and Function Quiz

Study Notes

Glycocalyx is a thin deformed layer surrounding the bacterial cell wall.
Functions include cell binding, nutrient trapping, surface adhesion, and protection against desiccation.
Staphylococcus species are known to form slime layers, contributing to biofilm development.

Fimbriae are found in both Gram-positive and Gram-negative bacteria.
Typically, 300-400 fimbriae are present per cell, characterized by their shorter and narrower structure.
Primarily involved in adhesion formation, regulated by nucleoid gene expression.
Pili occur only in Gram-negative bacteria, with 1-4 present per cell.
Pili are longer and broader than fimbriae and are involved in conjugation processes, controlled by the fertility factor (F+).

Polyphosphate granules serve dual purposes: energy storage and phosphate storage.
Degraded polyphosphate is converted into nucleotide triphosphate (ATP).
Sulfur within cells comes from reduced sulfur sources; when limited, sulfur granules may be oxidized to sulfate.
Certain cyanobacteria, like Gleomargarita, form carbonate minerals such as benstonite on surfaces, with some forming them intracellularly.

Polyphosphate acts as a precursor for ATP production, aiding in phosphate storage and future conversion.
Sulfur is crucial for energy metabolism (chemolithotrophy) and CO2 fixation (autotrophy) within cells.
Carbonate plays a role in biomineralization, a process catalyzed by various prokaryotes, stabilizing cellular environments and aiding habitat maintenance.

Glycocalyx forms a thin deformed layer around the bacterial cell wall.
Functions include binding to cells, trapping nutrients, adhering to surfaces, and protecting against desiccation.
Staphylococcus species are known to form slime layers.

Biofilms consist of communities of bacteria encased in a protective layer, enhancing survival and resistance.

Fimbriae are found in both Gram-positive and Gram-negative bacteria; pili are exclusive to Gram-negative bacteria.
Average of 300-400 fimbriae per cell, whereas pili number ranges from 1-4 per cell.
Fimbriae are shorter and narrower; pili are longer and broader.
Fimbriae facilitate adhesion; pili are involved in bacterial conjugation.
Fimbriae formation is influenced by nucleoid gene expression; pili formation is controlled by the fertility factor (F+).

Polyphosphate granules serve varied roles, including energy and phosphate storage, and are degraded to produce ATP.
Sulfur primarily sourced from reduced sulfur; limited supply prompts oxidation of granule sulfur to sulfate.
Carbonate minerals, like benstonite, form on filamentous cyanobacteria such as Gleomargarita, with some forming minerals intracellularly.

Polyphosphate aids in ATP synthesis, enabling phosphate storage and energy production.
Sulfur plays critical roles in energy metabolism (chemolithotrophy) and carbon fixation (autotrophy).
Carbonate is significant for biomineralization, helping stabilize cells in their environments.