BMS100: Eukaryotic Cells, Viruses, and Prions

Vocabulary practice flashcards covering eukaryotic cellular organelles, viral architecture and life cycles, and prion pathology from BMS100: Introduction to Human Biology.

Eukaryotic Cell

A cell characterized by the presence of a membrane-bound nucleus enclosed by a double membrane and membrane-bearing organelles, including animal, plant, and fungal cells.

Saccharomyces cerevisiae

Common baker's yeast, representing one of the simplest unicellular eukaryotic organisms.

Cytoplasm

The colloidal fluid containing all cellular organelles (cytosol, organelles, and nutrient storage), defined as everything that remains when all organelles are subtracted from a cell.

Plasma Membrane

A selectively permeable double lipid bilayer surrounding the cell, composed of phospholipids, embedded proteins, cholesterol, and carbohydrates.

Phospholipid

An amphipathic polar molecule consisting of a hydrophilic head (glycerol and phosphorylated alcohol) and two hydrophobic fatty acid tails, one of which contains a kink.

Nucleus

The cellular control center enclosed by a double membrane that protects the genetic material ($\text{DNA}$) and contains chromatin and nucleoli.

Nuclear Envelope

A double membrane perforated with nuclear pores that encloses the nucleus and separates its contents from the cytoplasm.

Nucleolus

A dense spherical subnuclear structure responsible for directing $\text{RNA}$ synthesis and assembling ribosomal subunits.

Ribosome

A non-membranous organelle composed of a large and small subunit made of proteins and ribosomal $\text{RNA}$ ($\text{rRNA}$), functioning in protein synthesis.

Rough Endoplasmic Reticulum (RER)

An interconnected network of flattened membrane sacs studded with ribosomes on its outer surface, specialized for protein synthesis and abundant in secretory cells.

Smooth Endoplasmic Reticulum (SER)

A tubular membrane network lacking ribosomes that functions in lipid and hormone synthesis, fat transport, detoxification, and glycogen breakdown.

Golgi Apparatus

An organelle composed of stacked, hollow membrane sacs ('stacked dinner plates') where proteins from the rough $\text{ER}$ are addressed, sorted, modified, and packaged into transport vesicles.

Lysosome

A single-membrane digestive organelle maintaining an acidic internal $\text{pH} \thickapprox 5.0$ with approximately $40$ acid hydrolases to degrade foreign bodies, cellular debris, and damaged organelles.

Peroxisome

A single-membrane organelle originating from the $\text{ER}$ that oxidizes fatty acids, carries out cholesterol synthesis via HMG-CoA reductase, and uses catalase to degrade hydrogen peroxide.

Catalase

A peroxisomal enzyme that converts toxic hydrogen peroxide into water and oxygen according to the reaction $2\text{H}_2\text{O}_2 \rightarrow 2\text{H}_2\text{O} + \text{O}_2$.

Mitochondrion

A semi-autonomous, double-membrane power-producing organelle containing its own $\text{DNA}$ and responsible for generating the majority of cellular chemical energy ($\text{ATP}$).

Cristae

Extensive foldings of the mitochondrial inner membrane that increase the surface area available for electron transport chain enzymes and $\text{ATP}$ synthesis.

Mitochondrial Matrix

The innermost compartment of the mitochondrion enclosed by the inner membrane, containing mitochondrial $\text{DNA}$ and enzymes for the Krebs cycle.

Cytoskeleton

An intracellular protein filament network that maintains and alters cell shape, directs cell motility and muscle contraction, aids cell division, and facilitates intracellular transport.

Microfilaments

Cytoskeletal elements measuring approximately $7\,\text{nm}$ in diameter, composed of twisted double strands of actin monomers.

Intermediate Filaments

Tough cytoskeletal fibers measuring approximately $8\text{--}12\,\text{nm}$ in diameter, composed of fibrous protein subunits such as keratins.

Microtubules

Hollow cylindrical cytoskeletal structures measuring approximately $25\,\text{nm}$ in diameter, composed of tubulin dimers formed from $\alpha$-tubulin and $\beta$-tubulin monomers.

Virus

A small non-cellular infectious agent consisting of nucleic acid ($\text{DNA}$ or $\text{RNA}$) encased in a protein capsid, lacking organelles and dependent on host cellular machinery for reproduction.

Bacteriophage T4

A complex virus that infects bacterial cells, composed of an icosahedral head containing $\text{DNA}$, a neck, a contractile tail sheath, and tail fibers.

Prion

A proteinaceous infectious particle lacking any genetic material that causes disease by inducing naturally occurring proteins to change their conformation and misfold into abnormal, beta-sheet-rich forms.

Bovine Spongiform Encephalopathy (BSE)

A fatal neurodegenerative prion disease of cattle, commonly referred to as 'Mad Cow Disease', that results in sponge-like degeneration of brain tissue.

Creutzfeldt-Jakob Disease (CJD)

A fatal human neurological prion disease causing rapid brain shrinkage, sponge-like tissue lesions, loss of motor control, dementia, and death typically within one year of onset.

Amyloid Plaques

Insoluble prion protein deposits that accumulate abnormally in the brain, driving the rapid degeneration and loss of neurons.