PROKARYOTIC CELLS NASAD TANGINA

Prokaryotic Cells

Are single-celled organism lacking a membrane-bound nucleus and other membrane-bound organelles

Bacteria & Archae

The Prokaryotic Cells belong to?

Coccus

Sphericaal or oval-shapes cells

Bacillus

Rod-shaped cells

Vibrio

Curved, comma-shaped cells

Spirochete

Flexible, corkscrew-shaped cells

Pleomorphic

Bacteria that can naturally alter their shape due to environmenta conditions or lack of a rigid cell wall

Mycoplasma

Example of a pleomorphic bacteria

Diplococci

Pairs of cells

Streptococci

Chains of cells

Tetrads

Packets of 4 cells dividing into two planes

Sarcinae

Cubical packets of eight cells dividing in 3 planes

Staphylococci

Irregular, grape-like clusters dividing in random places

Single Bacillus

Solitary rods

Diplobacilli

Pairs of rods end-to-end

Streptobacilli

Chains of rods

Coccobacillus

Oval-shaped rods that closely resemble cocci

Palisades

Cells lined up side-by-side like a picket fence

Cell Envelope

Multi-layered protective barrier that encloses the cytoplasm. It typically consists of a plasma mebrane, cell wall, and outer membrane in some bacyerias

Plasma Membrane

A phospholipid bilayer embedded with proteins. Unlike eukaryotes, bacteria membranes lack sterols like cholesterol, using hopanoids for stability

Cell Wal

It prevents osmotic lysis and maintains cell shape.

Hans Christian Gram

He discovered the cell wall in prokaryotic cells

Lipid A

This lipid acts as an endotoxin, triggering severe immune responses (like spetic chock)

Porins

This is from Lipid A, which form channels to regulate the entry of chemicals

Pseudomonas Aeruginosa

A notorious hospital-acquired pathogen taht causes severe lung and urinary tract infection. It is inherently resistant to many common antibiotics due to its incredibly selective outer membrane and efflux pumps

Acinetobacter Baumannii

Often called “Iraqibacter”, this multi-drug resistant Gram-negative bacterium is highly difficult to eradicate in ICU settings

Staphylococcus Pyogenes

Easily eliminated by standard beta-acta antibiotics (though mutated strains like MRSA gave developed specific resistance mechanism)

Streptococcus Pneumoniae

The primary cause of bacterial pnuemonia. It is readily targeted by standard penicillin or amoxicillin

Clostridium Difficile

This bacterium forms highly resilient spores. Alcohol-based hand rubs do not kill of C. Diff spores.

Glycocalyx

A gelatinous, sticky substance surrounding the outside of the cell, made of polysaccharides, polypeptides, or both

Capsule

An organized, firmly attached layer. It acts as a virulence factor by preventing phagocytosis by host immune cells

Slime Layer

An unorganized, loosely detached layerm it protects against dehydration and aids in biofilm formation

Monotrichous

Single flagellum at one pole

Lophotrichous

A tuft of flagella at one pole

Amphitrichous

Flagella at both poles

Peritrichous

Flagella distributed over the entire cell surface

Endoflagella

Found in spirochetes, wrap around the cell inside the periplasmic soace, producing a corkscrew motion

Fimbriae

Short, hair-like bristle appendages covering the cell surface. They are primarily used for attachment to surfaces or host tissues

Pili

Longer than the fimbriae but fewer in number. They mediate conjugation, a process where DNA is transferred from one bacterium to another

Nucleoid

The irregularly shaped region containing the single,circular bacterial chromosome (double-stranded DNA). It is not enclosed by a membrane.

Plasmids

Small, circular, extrachromosomal DNA molecules that carry non-essential but advantageous genes (e.g., antibioticction,

resistance).

Endospores

Dormant, highly resistant structures formed by certain gram-positive bacteria under extreme environmental stress. They can survive boiling, radiation, and desiccation for centuries