Structure-Prokaryotic-Cells

Prokaryotic Cell

A type of cell that lacks a membrane-bound nucleus and other membrane-bound organelles; includes bacteria and archaea.

Eukaryotic Cell

A cell that has a membrane-bound nucleus and other membrane-bound organelles; includes organisms such as plants, animals, fungi, and protists.

Nucleoid

The region in a prokaryotic cell where the circular DNA is located, not surrounded by a membrane.

Plasmid

Small, circular DNA molecule found in bacteria, separate from chromosomal DNA, often carrying antibiotic resistance genes.

Flagella

Long, whip-like appendages used for motility in bacteria.

Capsule

A well-defined polysaccharide layer that surrounds some bacteria, contributing to virulence by protecting against phagocytosis.

Biofilm

A collective of one or more types of microorganisms that can grow on many different surfaces; often composed of bacteria, fungi, and protists.

Glycocalyx

A sticky layer of polysaccharides on the outside of the bacterial cell wall that aids in attachment and biofilm formation.

Peptidoglycan

A polymer that forms a protective layer in the cell walls of bacteria, consisting of sugars and amino acids.

Gram-positive

Bacteria that retain the crystal violet stain used in the Gram staining procedure, indicating a thick peptidoglycan layer.

Gram-negative

Bacteria that do not retain the crystal violet stain and have a thin peptidoglycan layer and an outer membrane.

Endospore

A dormant, resistant structure produced by certain bacteria to survive harsh environmental conditions.

Osmotic pressure

The pressure required to prevent the movement of water into a solution containing solutes.

Isotonic solution

A solution where the concentration of solutes is equal inside and outside the cell, resulting in no net movement of water.

Hypotonic solution

A solution with a lower concentration of solutes outside the cell than inside, causing water to flow into the cell and possibly leading to lysis.

Hypertonic solution

A solution with a higher concentration of solutes outside the cell than inside, causing water to flow out of the cell and leading to plasmolysis.

Ribosome

Molecular machines in the cell composed of rRNA and protein that synthesize proteins by translating mRNA.

Fimbriae

Hair-like appendages that enable bacteria to adhere to surfaces and each other, playing a role in biofilm formation.

Antibiotic

A substance that can kill or inhibit the growth of bacteria, often targeting specific structures or processes in the bacterial cell.

Quorum sensing

The ability of bacteria to communicate and coordinate behavior based on population density through signaling molecules.

Nucleus

A membrane-bound organelle in eukaryotic cells that houses the cell's genetic material.

Cytoplasm

The gel-like substance within the cell membrane that contains all cellular components, excluding the nucleus.

Cell Wall

A rigid layer that provides structural support and protection to bacterial cells, preventing osmotic lysis.

Pili

Short, hair-like structures on the surface of bacteria that are involved in attachment, motility, and DNA transfer.

Endocytosis

The process by which a cell engulfs materials from the outside environment into vesicles.

Exocytosis

The process by which materials are expelled from a cell through vesicles fusing with the plasma membrane.

Metachromatic granules

Large inclusions that store phosphate; can be stained and are characteristic of certain bacterial species.

Sulfur granules

Deposits of elemental sulfur in bacteria that can be used as energy reserves.

Magnetosomes

Crystals of magnetite in some bacteria that allow them to orient themselves with the Earth's magnetic field.

Antiseptic

Substances that kill or inhibit the growth of microorganisms, used for sanitizing surfaces and wounds.

Tetracycline

An antibiotic that interferes with protein synthesis in bacteria by binding to the ribosomal subunit.

Enzyme

Biological catalysts that speed up chemical reactions in cells.

Cytoplasmic membrane

A selective barrier that regulates the entry and exit of substances in and out of the cell.