{Prokcell } Cell Envelope and its Modification Flashcards
(17 cards)
What is the structure of the cell envelope in prokaryotic cells?
The cell envelope consists of a tightly bound three-layered structure: the outermost glycocalyx, followed by the cell wall, and then the plasma membrane.
How are bacteria classified based on their cell envelopes?
Bacteria are classified into Gram positive (those that take up the gram stain) and Gram negative (those that do not take up the gram stain).
What are the two forms of glycocalyx found in bacteria?
Glycocalyx can be a loose sheath called the slime layer or a thick and tough structure called the capsule.
What is the function of the cell wall in bacteria?
The cell wall determines the shape of the cell and provides strong structural support to prevent bursting or collapsing.
What is the nature of the plasma membrane in prokaryotic cells?
The plasma membrane is selectively permeable and interacts with the outside world.
What is a mesosome?
A mesosome is a special membranous structure formed by extensions of the plasma membrane into the cell.
What functions do mesosomes serve?
Mesosomes help in cell wall formation, DNA replication, distribution to daughter cells, respiration, secretion processes, and increasing the surface area of the plasma membrane and enzymatic content.
What are chromatophores in some prokaryotes?
Chromatophores are membranous extensions into the cytoplasm that contain pigments, found in some prokaryotes like cyanobacteria.
What are flagella and their role in bacteria?
Flagella are thin filamentous extensions from the cell wall that enable motility in bacteria.
What are the three parts of a bacterial flagellum?
A bacterial flagellum is composed of three parts: filament, hook, and basal body.
What are pili and fimbriae?
Pili are elongated tubular structures made of a special protein, while fimbriae are small bristle-like fibers sprouting from the cell.
What role do fimbriae play in bacteria?
Fimbriae help attach bacteria to surfaces, such as rocks in streams and host tissues.
What is a mesosome?
A special membranous structure formed by extensions of the plasma membrane into the cell.
What forms the extensions of the mesosome?
Extensions are in the form of vesicles, tubules, and lamellae.
What functions do mesosomes serve?
They help in cell wall formation, DNA replication, distribution to daughter cells, respiration, secretion processes, and increasing the surface area of the plasma membrane and enzymatic content.
What are chromatophores?
Membranous extensions into the cytoplasm found in some prokaryotes like cyanobacteria, which contain pigments.
