Wednesday, 15 March 2017

The prokaryotic Cell

Species definition;
"population of cells with similar characteristics"

Cell wall;
- Peptidoglycan
- Outer membrane

The DNA of Bacteria is contained in a circular chromosome, folded into many loops

Bacteria have both a plasma membrane and cell wall

Bacteria often have a small circles of additional DNA called plasmids.

SHARED CHARACTERISTICS

  1. Plasma or cell membrane
  2. Nucleoid
  3. Cytoplasm; Cytosol + Insoluble Particles
  4. Ribosomes

DISTINCTIVE CHARACTERISTICS

  1. Cell walls
  2. Capsules
  3. Internal membranes
  4. Flagella
  5. Pili
  6. Fimbriae
  7. Cytoskeleton

PLASMA MEMBRANE;
is a selective barrier enclosing the cell that separates the interior and exterior of the cell from the environment. It is semi permeable, it allows gases, nutrients and waste in and out of the cell. (Bilayer of Phospholipids with proteins attached to or embedded in it)

NUCLEIOD;
The region in the prokaryotic cell where DNA is located

CYTOPLASM;
Composed of cytosol; mostly water and soluble particles

RIBOSOMES;
complex of RNA and proteins which function as sites for proteins synthesis (RNA-PROTIENS)

CELL WALL;
Outside the plasma membrane, bacteria contains peptidoglycan that covers the entire cell:
- gives rigidity
- Support and shape

CAPSULE;
layer of polysaccharides enclosing the cell wall.
protects the bacteria from the immune function and desiccation, also helps attachment

INTERNAL MEMBRANE;
A system of folded bilayer membrane that contains molecules needed for;
- Photosynthesis
- Cell division
- energy releasing reactions

FLAGELLA;
Corkscrew- like appendage used for movement.
composed of flagellin and protein ring structures anchored in plasma membrane forming a rotor

PILI;
Hair like structure, shorter then flagella.
Made of protein projecting from the surface of many bacteria
Used for adherence.

FIMBRIAE;
Shorter then the pili.
Used for adherence to animal cells, food and protection

CYTOSKELETON;
Network of filaments structures, extends length of cell.
Inside the plasma membrane. present in rod shape Bactria (E.Coli)

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