Chapter 3: The Cell & Chapter 19: Diseases of the Immune System

Vocabulary flashcards covering cell structure and function, cell theory, endosymbiosis, hypersensitivities, autoimmunity, transplantation, and immunodeficiencies.

Spontaneous Generation

The historical belief that living organisms can arise spontaneously from nonliving matter.

Francesco Redi's Experiment

An experiment using open, cork-sealed, and gauze-covered containers of meat that demonstrated maggots come from flies rather than spontaneous generation.

John Needham

A scientist who supported spontaneous generation by briefly boiling broth and observing microbial growth.

Lazzaro Spallanzani

A scientist who disproved Needham by boiling broth for a longer duration in sealed flasks, showing no microbial growth.

Louis Pasteur

The scientist who disproved spontaneous generation using swan-neck flasks, showing that air is allowed in while microbes are blocked.

Modern Cell Theory

Biological theory stating that cells are the basic unit of life and that all cells arise from preexisting cells.

Robert Hooke

The scientist who first named and described cells based on microscopic observations of cork, published in Micrographia.

Robert Remak

A scientist who first published in 1852 that all cells originate from other cells through cell division.

Rudolf Virchow

A scientist who popularized cell theory in an 1855 essay entitled "Cellular Pathology" using the phrase "All cells arise from cells."

Endosymbiotic Theory

The theory that mitochondria and chloroplasts derived from prokaryotic bacteria establishing a symbiotic relationship inside eukaryotic host cells.

Germ Theory of Disease

The concept that specific diseases are caused by pathogenic microorganisms, replacing the miasma theory.

Miasma Theory

An ancient theory proposing that diseases were caused by bad air or environmental pollution.

Gram-Positive Bacteria

Bacteria with a thick cell wall composed of many layers of peptidoglycan embedded with teichoic acids ($30\text{--}100\,\text{nm}$ thick).

Gram-Negative Bacteria

Bacteria with a thin peptidoglycan layer ($< 4\,\text{nm}$) surrounded by an outer membrane containing lipopolysaccharides.

Glycocalyx

A cell surface layer consisting of capsules or slime layers that protects the cell, aids in adherence, and forms biofilms.

Fimbriae

Short, numerous, bristle-like protein appendages on bacterial surfaces used primarily for attachment.

Pili

Longer and less numerous protein appendages on bacteria used for attachment and DNA transfer via the F or sex pilus.

Flagellar Arrangements

Specific patterns of bacterial flagella placement including monotrichous, amphitrichous, lophotrichous, and peritrichous.

Chemotaxis

Overall directional movement of a bacterium toward higher concentrations of a chemical attractant.

Run and Tumble Motility

Flagellar motility mechanism where counterclockwise rotation produces a forward run (bundled flagella) and clockwise rotation produces a tumble (separated flagella).

Plasmids

Extrachromosomal circular DNA molecules in prokaryotes that frequently carry antibiotic resistance genes and pathogenicity islands.

Endospores

Specialized bacterial structures formed to protect the genome and allow survival under extreme or harsh environmental conditions.

Type I Hypersensitivity

An immediate allergic reaction mediated by allergen-specific IgE antibodies bound to mast cells, inducing degranulation upon secondary exposure.

Type II Hypersensitivity

Cytotoxic reaction mediated by IgG or IgM antibodies binding cell-surface antigens, resulting in complement activation, cell lysis, or ADCC.

Hemolytic Transfusion Reaction (HTR)

A Type II hypersensitivity where recipient IgM or IgG isohemagglutinins bind donor red blood cells, causing classical complement activation and hemolysis.

Hemolytic Disease of the Newborn (HDN)

A Type II hypersensitivity caused by Rh incompatibility where maternal IgG antibodies cross the placenta to destroy fetal red blood cells.

Type III Hypersensitivity

Immune complex hypersensitivity where IgG or IgM and soluble antigens deposit in tissue, triggering complement activation and neutrophil-driven damage.

Type IV Hypersensitivity

Cell-mediated hypersensitivity driven exclusively by T-cell responses without antibody involvement.

Autograft

Tissue transplanted from one site to another on the same individual, posing zero risk of immune rejection.

Isograft

Tissue transplanted between genetically identical individuals, such as identical twins, carrying minimal rejection risk.

Allograft

Tissue transplanted between genetically different individuals belonging to the same species.

Xenograft

Organ or tissue transplanted from an animal species into a human recipient.

Human Leukocyte Antigens (HLAs)

Highly polymorphic MHC Class I and II molecules that serve as the primary targets of transplant rejection.

Graft-versus-Host Disease (GVHD)

Complication mainly in bone marrow transplants where donor T cells and antigen-presenting cells attack recipient tissues.

Primary Immunodeficiency

An inherited genetic defect in innate or adaptive immunity present from infancy or childhood, such as CGD or SCID.

Secondary Immunodeficiency

An acquired loss of immune function caused by systemic factors, chemotherapy, radiation, malnutrition, or HIV/AIDS.

Tine Test Device

A specialized multi-pronged instrument used to administer tuberculin antigen into the skin to test for Type IV hypersensitivity.

Exophthalmia

Protrusion of the eyes, also known as Graves ophthalmopathy, which is a key sign of Graves disease.

Hyperpigmentation

Darkening of the skin, particularly visible on the palms, serving as a primary clinical sign of Addison disease.

Rheumatoid Arthritis Hand Deformities

Joint damage and skeletal distortion in hands typical of rheumatoid arthritis caused by immune complex deposition and chronic inflammation.