The Study of Structure and Function of Human Cell

Vocabulary flashcards covering the structural components, organelles, physiological functions, and associated pathologies of human and comparative cellular biology.

Typical Cells (Animal, Plant, and Bacteria)

The three major cell categories shown in comparative structural biology: animal and plant cells possess membrane-bound organelles such as a distinct nucleus, whereas bacterial cells lack membrane-bound organelles and display unique external structures like flagella, a capsule, and mesosomes.

Cell

The fundamental structural and operational unit of life activities upon which all organisms depend, with multicellular organisms such as humans comprising approximately $34\text{ trillion}$ cells.

Cell Membrane

A semipermeable outer structure composed of a phospholipid bilayer with hydrophilic heads on the outside and hydrophobic tails on the inside, regulating substance transport via potential-controlled channels and maintaining internal stability.

Pyroptosis

A form of cell death characterized by cellular swelling and membrane rupture that releases massive inflammation, contributing to insulin metabolic disorders, diabetes, and CD4 T-cell depletion in HIV/AIDS.

Cytoplasm

A jelly-like intracellular fluid composed of water, ions, organic molecules, and organelles that provides structural support, acts as a solvent for biochemical reactions, and facilitates vesicle-mediated molecular transport.

Nuclear Envelope (Karyotheca)

A double phospholipid bilayer consisting of an inner and outer nuclear membrane separated by a gap, which encloses the nucleus, protects genetic material, and disassembles during cell division to facilitate chromosome segregation.

Nuclear Pores

Specialized openings on the nuclear envelope that regulate the bidirectional exchange of molecules, including RNA and ribonucleoproteins, between the nucleus and cytoplasm for gene expression and ribosome synthesis.

Euchromatin

A loosely packed state of chromatin within eukaryotic nuclei that allows active gene expression.

Heterochromatin

A densely packed state of chromatin within eukaryotic nuclei that represses gene expression.

Nucleolus

A non-membrane-bound subnuclear structure composed of ribonucleic acid and proteins, primarily responsible for the synthesis, processing, and assembly of cellular ribosomal subunits.

Granule Region

The component of the nucleolus that is rich in rRNA, serving as an essential site for the assembly and synthesis of cellular ribosomes.

Fiber Region

The subregion of the nucleolus containing precursors of rRNAs where they undergo enzymatic processing and modification.

Granule-Fiber Region

The transitional zone between the granule region and fiber region in the nucleolus, containing critical structural and functional maintenance proteins.

Treacher Collins Syndrome

A rare genetic disorder characterized by facial deformities and physical defects resulting from nucleolar dysfunction during embryonic development.

Rough Endoplasmic Reticulum (RER)

A membrane network of flattened cisternae studded with ribosomes on its cytoplasmic surface, primarily functioning in the synthesis, folding, and glycosylation of proteins destined for membranes, secretion, or intracellular organelles.

Smooth Endoplasmic Reticulum (SER)

A ribosome-free tubular membrane network continuous with the rough ER, dedicated to lipid synthesis (such as phospholipids and steroids) and the enzymatic detoxification of drugs and metabolic toxins.

ER Storage Diseases

A category of disorders, including cystic fibrosis and certain forms of diabetes, caused by the accumulation of misfolded proteins within the endoplasmic reticulum lumen.

Mitochondria

The double-membraned 'power station of cells' containing its own unique DNA, responsible for generating ATP through aerobic metabolism and regulating apoptosis, cell differentiation, and the cell cycle.

Ribosome

A non-membrane-bound molecular machine composed of rRNA and proteins, divided into a small subunit that reads mRNA and a large subunit that catalyzes peptide bond formation during translation.

Translation

The biological process in which ribosomes decode messenger RNA (mRNA) into functional polypeptide chains across three sequential stages: initiation, elongation, and termination.

Diamond-Blackfan Anemia (DBA)

A rare genetic ribosomopathy caused by mutations in ribosomal protein genes that disrupt normal ribosome assembly and cause defective red blood cell production.

Shwachman-Diamond Syndrome (SDS)

A congenital ribosomopathy characterized by defective ribosome biogenesis, leading to impaired bone marrow function, reduced blood cell production, and digestive dysfunction.

Golgi Apparatus

An organelle consisting of stacked membranous cisternae that modifies (via glycosylation, phosphorylation, and sulfation), sorts, and packages proteins and lipids into transport vesicles.

Cis Face (Golgi)

The receiving cisternae of the Golgi apparatus oriented toward the endoplasmic reticulum, which receives transport vesicles carrying newly synthesized proteins and lipids.

Trans Face (Golgi)

The shipping cisternae of the Golgi apparatus where processed macromolecules are sorted and packaged into secretory or transport vesicles directed to their target destinations.

Sialidosis

A rare Golgi storage disease caused by the abnormal intra-Golgi accumulation of sialic acid, resulting in severe neurological and systemic symptoms.

Flagella

Slender, curved locomotive structures characteristic of bacterial cells that facilitate cellular movement and motility.