Cell Structure

Prokaryotic cells

Cells that lack a nucleus and other membrane-bound organelles.

Morphology

The study of the form and structure of organisms.

Coccus

A spherical shape of prokaryotic cells.

Rod

A cylindrical shape of prokaryotic cells.

Cell wall

A rigid structure outside the cell membrane that determines the shape of the organism and prevents bursting.

Capsules and slime layers

Coatings of hydrated glycopolymers that provide protection or attachment to the cell wall.

Filamentous appendages

Protein appendages anchored in the cell membrane, such as flagella and pili.

Cytoplasmic membrane

The boundary of the cell that surrounds the cytoplasm and controls the movement of molecules.

DNA

The genetic material of the cell, located in the nucleoid region.

Ribosomes

Structures responsible for protein synthesis.

Endospores

Dormant bacterial cells produced in response to environmental stress.

Bacterial cell wall

A rigid structure composed of peptidoglycans that provides shape and protection.

Gram-positive cell wall

Thick peptidoglycan layer with teichoic acids and stains purple in the Gram stain.

Gram-negative cell wall

Thin peptidoglycan layer with an outer membrane and lipopolysaccharides, stains pink in the Gram stain.

Lipopolysaccharides

Molecules in the outer layer of Gram-negative cell walls that can cause bacterial infection.

Peptidoglycans

Alternating subunits of NAM and NAG that provide rigidity to the bacterial cell wall.

Antibacterial substances

Substances that target the peptidoglycan in bacterial cell walls, such as penicillin and lysosome.

Cytoskeleton

Proteins in prokaryotic cells that are involved in cell division and shape.

Gas vesicles

Structures that provide buoyancy to some prokaryotic cells.

Granules

Storage structures in prokaryotic cells for nutrients or other substances.

Magnification

The apparent increase in size of an object under a microscope.

Resolution

The ability to distinguish two closely spaced objects as separate.

Contrast

The difference in intensity between an object and its background, affecting visibility.

Transmission electron microscope (TEM)

A microscope that uses electrons passing through a specimen to observe fine details of cell structure.

Scanning electron microscope (SEM)

A microscope that uses electrons scanning over a specimen to produce a 3D image of the surface details.

Simple stains

Stains that use a single dye to increase contrast in a specimen.

Differential stains

Stains that distinguish between different groups of microorganisms, such as the Gram stain and acid-fast stain.

Special stains

Stains used to observe specific structures or components of microorganisms, such as capsule stains and endospore stains.

Fluorescent stains

Stains that use fluorescent dyes or tags to visualize specific proteins or structures in a specimen.