Components of the Prokaryotic Cell

Flashcards covering the components and structures of prokaryotic cells, including cell wall differences, organelles, and genetic material.

Cell

The simplest/basic unit of life.

Archaea

One of the three domains of organisms consisting of prokaryotes.

Bacteria

One of the three domains of organisms consisting of prokaryotes.

Eukarya

One of the three domains of organisms consisting of eukaryotes, including the kingdoms Protista, Fungi, Plantae, and Animalia.

Prokaryote

A type of cell that lacks membrane-bound organelles; the only organelle present is the ribosome.

Cell Wall

A protective, unique structure surrounding the cell membrane that maintains the characteristic shape and contains pores for the flow of water, dissolved substances, and wastes.

Peptidoglycan

The key component of the bacterial cell wall.

N-acetylglucosamine (NAG)

One of the sugar derivatives that make up the backbone of peptidoglycan.

N-acetylmuramic acid (NAM)

One of the sugar derivatives that make up the backbone of peptidoglycan, which has a tetrapeptide chain attached.

Peptide interbridge

The component that links the backbones of the peptidoglycan layer together.

Teichoic acid

A component found in Gram-positive cell walls that increases rigidity and strength.

Porin

A protein found in the outer membrane of Gram-negative cell walls that acts as a channel for molecules.

Lipopolysaccharide (LPS)

A component of the Gram-negative outer membrane consisting of O antigen polysaccharide, core polysaccharide, and Lipid A.

Gram-positive bacteria

Bacteria characterized by a thick peptidoglycan layer and teichoic acids; they are generally more susceptible to penicillin and lysozyme.

Gram-negative bacteria

Bacteria characterized by a thin peptidoglycan layer, an outer membrane, and a periplasmic space; they are generally less susceptible to penicillin and resistant to lysozyme.

Cell Membrane

Also known as the plasma or cytoplasmic membrane, it is a thin layer composed of a phospholipid bilayer interspersed with proteins on the inner surface of the cell wall.

Selectively permeable

A property of the cell membrane that allows easy diffusion of small molecules (water, oxygen, carbon dioxide) while regulating the passage of larger molecules (amino acids, sugars).

Cytoplasm

A semi-fluid substance that fills the cell, composed of approximately $65\,\%$ water along with proteins, vitamins, ions, nucleic acids, and other nutrients.

Nucleoid

The region within the cytoplasm of a prokaryote where the chromosomal DNA is located.

Chromosomal DNA

A single circular chromosome consisting only of DNA, lacking the histones found in eukaryotes.

Ribosome

Referred to as the cell’s protein factories, these are the sites of protein synthesis located in the cytoplasm.

70S Ribosome

The prokaryotic ribosome structure, composed of a $30S$ small subunit and a $50S$ large subunit.

Flagella

A sensory unit used primarily for locomotion, allowing bacteria to move toward favorable environments or away from hostile ones.

Monotrichous

A bacterial flagella arrangement consisting of a single flagellum.

Peritrichous

A bacterial flagella arrangement where flagella are distributed over the entire cell surface.

Capsule

A thick, sticky covering tightly attached to the cell wall that provides protection from white blood cells, chemicals, and dehydration.

Slime layer

A covering loosely associated with the bacterium, distinct from a tightly attached capsule.

Pili

Hair-like projections that enable bacteria to adhere to surfaces/cells and are involved in the process of conjugation.

Conjugation

The process where genetic material is transferred from one bacterium to another, facilitated by pili.

Plasmid

Small, circular, double-stranded extra-chromosomal DNA that can replicate autonomously and often contains beneficial genes like antibiotic resistance.

Fertility plasmids

Plasmids containing genes that code for the sex pilus and enzymes required for conjugation.