Cell Biology: Structure, Properties, and Organization

Vocabulary practice flashcards covering cell evolution, prokaryotic and eukaryotic structures, physical and chemical properties of the protoplasm, and biomembrane organization.

Progenote (Proto-cell)

The earliest entity considered life that appeared approximately $4\text{ billion years ago}$, delimited by a membrane, containing self-replicating genetic material, and capable of passing traits to offspring.

Prokaryotic cell

A unicellular organism lacking a true membrane-bound nucleus, typically having a diameter of $1\,\mu\text{m}$, circular DNA without structural proteins in the cytoplasm, no cytoskeleton, and reproducing by simple fission.

Eukaryotic cell

A complex cell containing a true membrane-bound nucleus, measuring $10-100\,\mu\text{m}$ in diameter, featuring a developed cytoskeleton, multiple DNA and RNA molecules complexed with structural proteins, and dividing via mitosis and meiosis.

Plasmid

A small, circular DNA molecule found in prokaryotic cells that functions independently of chromosomal DNA and often carries genes for antibiotic resistance.

Colloid system

A multi-component state of matter containing dispersed particles in the $1-1000\,\text{nm}$ size range, characterized by high friction, surface tension, elasticity, slow diffusion, and weak osmotic pressure.

Protoplasm

The colloid foundation of the cell wherein water acts as the dispersion medium and organic particles (micelles) act as the dispersed phase, undergoing reversible transitions between liquid (sol) and gel states.

Starch

A carbohydrate that serves as the principal energy storage material in plant cells.

Glycogen

A storage carbohydrate utilized as an energy reserve in animal cells, bacteria, and fungi.

Cellulose

A structural carbohydrate that forms the primary constituent of plant cell walls.

Enzymes

Substrate-specific catalytic proteins that regulate the direction, rate, and sequence of biochemical metabolic reactions occurring in the cell.

Nucleic acids

Macromolecules (DNA and RNA) primarily concentrated in the cell nucleus that are responsible for protein synthesis and the transmission of genetic information.

Human bacterial ecosystem

The microbial community hosted by the human body, comprising roughly $100\text{ trillion}$ bacterial cells primarily residing on skin surfaces and within the digestive tract.

Hyaloplasm

The clear, homogeneous fraction of eukaryotic cytoplasm containing enzymes, lipids, and globulin proteins, devoid of cellular organelles.

Granuloplasm

The granular fraction of the eukaryotic cytoplasm that contains and suspends the cellular organelles.

Biomembrane

Membranous structures that account for approximately $80\%$ of eukaryotic dry cell weight, composed of lipids, proteins, and carbohydrates, offering an evolutionary advantage over prokaryotes.

Phospholipids (Membrane)

Lipid molecules constituting $40-60\%$ of biomembranes, structured with a hydrophilic head and hydrophobic tails to form the structural foundation of the bilayer.

Membrane proteins

Proteins making up $40-60\%$ of biomembranes, existing as peripheral proteins, pore proteins, or integral/transmembrane proteins involved in structural integrity and transport.

Golgi apparatus (Dictyosomes)

A eukaryotic membrane-bound organelle system composed of flattened cisternae involved in the modification, sorting, and packaging of cellular products.

Endoplasmic reticulum

An extensive eukaryotic intracellular membrane network existing as either smooth endoplasmic reticulum (lacking ribosomes) or rough endoplasmic reticulum (studded with ribosomes).