Cytoplasmic Membrane Structure and Transport

A biological membrane that encloses the cytoplasm of a cell, separating it from the external environment. It acts as a barrier, controlling what enters and exits the cell.

The fluid, gel-like substance within the cell membrane, containing all the organelles and other cellular components.

Specialized fatty molecules that form the structural basis of the cytoplasmic membrane. They have a unique structure consisting of a hydrophilic head and a hydrophobic tail.

A property of the cytoplasmic membrane that allows it to control the passage of molecules in and out of the cell. The membrane lets some substances pass through easily, while others are blocked.

Proteins embedded within the cytoplasmic membrane, crucial for various cellular processes such as transport, signaling, and adhesion.

Membrane proteins that facilitate the movement of specific molecules across the membrane.

A type of transport protein that creates a hydrophilic channel allowing water and small polar molecules to pass through the membrane.

Specialized lipids that increase the stability of bacterial membranes. Think of them as structural reinforcements.

Unique lipids found in hyperthermophilic Archaea. They contain cyclopentyl and cyclohexyl rings, making them more rigid.

The membrane acts as a barrier, maintaining a stable internal environment despite external fluctuations. It prevents unrestricted diffusion of substances, ensuring a controlled environment for cell processes.

The gel-like space between the inner and outer membranes of Gram-negative bacteria, containing enzymes and proteins.

Specialized proteins in the outer membrane of Gram-negative bacteria that allow the passage of small molecules and nutrients into the periplasm; they can be specific or non-specific.

A type of active transport system found in bacteria, consisting of periplasmic binding proteins, membrane transporters, and ATP-hydrolyzing proteins to efficiently transport substances across the membrane.

A major component of bacterial cell walls, made of alternating units of N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM). It provides structural integrity, rigidity, and shape to bacterial cells.

A staining technique that differentiates bacteria based on their cell wall structure. Gram-positive bacteria retain the crystal violet stain, appearing purple, while Gram-negative bacteria lose the stain and take up the counterstain, appearing pink or red.

A type of cell wall found in some Archaea, containing N-acetylglucosamine and N-acetyltalosaminuronic acid instead of N-acetylmuramic acid. It provides structural support similar to peptidoglycan.

Hair-like appendages found only in Gram-negative bacteria, typically 1-4 per cell. They are involved in conjugation processes, where genetic material is transferred between bacteria.

Short, bristle-like appendages found in both Gram-positive and Gram-negative bacteria. They help bacteria adhere to surfaces, form biofilms, and sometimes contribute to virulence.

A protective layer surrounding bacterial cells that enhances survival, resistance, and biofilm formation.

A complex process where bacteria use flagella to move through their environment.

These structures, 15-20 nm in size, enable bacteria to move through their environment by 'swimming'.

A paracrystalline layer of interlocking proteins or glycoproteins that acts as a selective sieve, retaining proteins close to the cell surface and providing structural support.

A thin, deformed layer surrounding bacterial cell walls, composed of polysaccharides and glycoproteins. It helps with cell binding, nutrient trapping, surface adhesion, and protection against desiccation.

Short, bristle-like appendages found on bacterial surfaces, involved in adhesion to surfaces and other cells. They are essential for biofilm formation and colonization.

A unique cell wall polymer found in Archaea, differing from peptidoglycan in glycosidic bond structure and stereochemistry. It provides strength and rigidity to the cell wall.

A type of polysaccharide found in bacteria and some eukaryotes, serving as an energy storage and phosphate reservoir. It can be converted to ATP, providing energy for various cellular processes.

The process by which prokaryotes utilize sulfur for energy metabolism, often in environments lacking oxygen.

The process by which organisms use carbon dioxide as their primary carbon source to produce organic compounds. It is often coupled with chemolithotrophy in sulfur-oxidizing bacteria.

A process involving the formation of mineral structures, often catalyzed by prokaryotes. It plays a significant role in stabilizing cellular environments and shaping habitats.

A type of mineral, often formed by prokaryotes, that is important for maintaining cellular environments and providing a stable habitat.

A process by which bacteria use sulfur as an electron donor for energy generation. It is a crucial step in the sulfur cycle, playing a significant role in ecosystems.

Polyphosphate granules store energy and phosphate, releasing ATP when broken down.

Sulfur is primarily sourced from reduced sulfur. When limited, the cell oxidizes sulfur granules to sulfate.

Filamentous cyanobacteria like Gleomargarita form carbonate minerals like benstonite.

Flagella are helical structures found over the entire surface of the cell, propelling bacterial movement.

Flagella are composed of a filament, hook, and motor, powered by the proton motive force.

Flagella act like a motor, rotating to propel the cell forward or backward.

Bacteria move towards attractants and away from repellents using flagellar motion.

Peritrichous flagellated bacteria move forward in runs and tumble when they stop and jiggle.

Polar flagellated bacteria can reverse flagellar rotation to change movement direction.

Archaeal flagella are composed of different flagellin proteins and powered directly by ATP.