Table of Contents
What part of a bacterial cell allows cells to move?
Flagella – Flagella (singular, flagellum) are hairlike structures that provide a means of locomotion for those bacteria that have them. They can be found at either or both ends of a bacterium or all over its surface.
What protects the cell from lysis?
A wall located outside the cell membrane provides the cell support, and protection against mechanical stress or damage from osmotic rupture and lysis. The major component of the bacterial cell wall is peptidoglycan or murein.
How does capsule protect the bacteria?
Capsules can protect a bacterial cell from ingestion and destruction by white blood cells (phagocytosis). While the exact mechanism for escaping phagocytosis is unclear, it may occur because capsules make bacterial surface components more slippery, helping the bacterium to escape engulfment by phagocytic cells.
What does the cell envelope of a bacteria consist of?
There are three principal layers in the envelope; the outer membrane (OM), the peptidoglycan cell wall, and the cytoplasmic or inner membrane (IM). The two concentric membrane layers delimit an aqueous cellular compartment that Peter Mitchell (1961) first termed the periplasm.
What are the two major types of bacterial cell walls?
There are two main types of bacterial cell walls, those of gram-positive bacteria and those of gram-negative bacteria, which are differentiated by their Gram staining characteristics. For both these types of bacteria, particles of approximately 2 nm can pass through the peptidoglycan.
What happens to a bacterial cell in a hypertonic solution?
Bacteria and fungi are dehydrated by hypertonic solutions, causing cell functions to shut down. A hypertonic solution has a higher solute concentration and a lower water concentration than the cell. This will cause the process of osmosis to cause a net movement of water out of the cell and into the solution.
Which cell has no nucleus?
Prokaryotes are organisms whose cells lack a nucleus and other organelles. Prokaryotes are divided into two distinct groups: the bacteria and the archaea, which scientists believe have unique evolutionary lineages. Most prokaryotes are small, single-celled organisms that have a relatively simple structure.
Which bacteria are spore forming?
Spore-forming bacteria include Bacillus (aerobic) and Clostridium (anaerobic) species. The spores of these species are dormant bodies that carry all the genetic material as is found in the vegetative form, but do not have an active metabolism.
Is capsule present in all bacteria?
Not all bacterial species produce capsules; however, the capsules of encapsulated pathogens are often important determinants of virulence. Encapsulated species are found among both Gram-positive and Gram-negative bacteria.
Is capsule part of cell envelope?
Cellular component – Cell envelope In bacteria with 1 membrane (Gram-positive) the cell envelope consists of the cytoplasmic membrane, cell wall and capsule. In bacteria with 2 membranes (Gram-negative) the envelope consists of the cytoplasmic membrane, cell wall, periplasmic space, outer membrane and capsule.
What are the main components of the cell envelope?
Cell envelope consists of 3 components— glycocalyx, cell wall and cell membrane.