Prokaryotic Structure and Cell Wall

The outer boundary of a prokaryotic cell, composed of a phospholipid bilayer with embedded proteins. It acts as a selective barrier, controlling what enters and exits the cell.

The process by which water moves across a semi-permeable membrane from an area of high water concentration to an area of low water concentration.

A potential energy source for prokaryotic cells. It arises from a difference in concentration of hydrogen ions (protons) across the cell membrane. This gradient is used to drive ATP production and other metabolic processes.

Movement of molecules across a cell membrane without requiring energy. This happens when molecules move from an area of high concentration to an area of low concentration.

Movement of molecules across a cell membrane that requires the help of transport proteins. These proteins facilitate the movement of molecules across the membrane, either down or against their concentration gradient.

A solution with a lower solute concentration compared to the cell. Water moves into the cell.

A solution with a higher solute concentration compared to the cell. Water moves out of the cell.

A solution with the same solute concentration as the cell. No net water movement occurs.

A rigid structure outside the bacterial cell membrane that provides shape and protects against osmotic pressure. Comprised of peptidoglycan.

The main structural component of bacterial cell walls. Provides rigidity, helps resist osmotic stress, and gives shape.

A differential staining process that classifies bacteria into Gram-positive and Gram-negative based on cell wall structure.

Bacteria with a thick layer of peptidoglycan that retains the crystal violet stain. Usually susceptible to penicillin.

Bacteria with a thinner layer of peptidoglycan and an outer membrane, which prevents the crystal violet stain from being retained. Usually resistant to penicillin.

A type of lipopolysaccharide (LPS) found in E. coli bacteria, known for causing severe food poisoning and diarrheal illness.

A complex molecule found in the outer membrane of Gram-negative bacteria. It triggers a strong immune response in humans, leading to various inflammatory and toxic effects.

Severe, life-threatening condition caused by an overwhelming immune response, often triggered by bacterial infections. It leads to dangerously low blood pressure and widespread inflammation throughout the body.

A protein layer found on the surface of some bacteria. It provides structural integrity, offers protection against environmental challenges, and helps bacteria resist antibiotics.

Capsules, slime layers, and films are protective layers outside the bacterial cell wall, primarily composed of polysaccharides. They help bacteria evade the immune system, adhere to surfaces, and facilitate communication.

Bacteria that possess a unique cell wall structure with a high content of mycolic acid, a waxy lipid. This makes them resistant to many antibiotics and staining techniques.

Bacteria that lack a peptidoglycan cell wall and instead rely on a membrane containing sterols for structural support. They are typically small and pleomorphic, meaning they vary in shape.

The region within a bacterial cell where the DNA is located, but not enclosed by a membrane like in eukaryotic cells.

Storage structures within bacteria that accumulate various materials such as energy substrates, metabolic precursors, and even orientation markers. These inclusions can be characteristic of specific bacterial species, aiding in identification.

Microscopic filament-like structures extending from the bacterial cell surface, often involved in attaching to surfaces, a crucial step in colonization and disease development. Certain pili (sex pili) play a role in transferring genetic information between bacteria.

Resistant, dormant forms of certain bacteria, capable of surviving harsh environmental conditions. They are formed inside bacterial cells and are highly resistant to disinfection methods. Endospore formation poses a significant medical challenge, as these structures can persist even in the human body.

A survival mechanism employed by some bacteria, involving encapsulation within a protective, dormant form. These spores are highly resistant to heat, radiation, and chemicals.

Long whip-like appendages that propel bacteria through their surroundings. Flagellar rotation is driven by a proton motive force (PMF), a source of potential energy in bacteria.

A group of photosynthetic bacteria that utilize chlorophyll a and produce oxygen. These bacteria are often found in aquatic environments and possess thylakoids, similar to those found in plant cells.

A diverse group of photosynthetic bacteria that rely on bacteriochlorophyll for energy capture. They typically inhabit anaerobic environments, those lacking oxygen, and utilize sulfur in their energy processes.

A unique domain of life, separate from both bacteria and eukaryotes, with distinct evolutionary origins. Archaea are often found in extreme environments and possess unique adaptations that distinguish them from other living organisms.