Cell Structure, Function, and Compartmentalization Flashcards

A set of vocabulary flashcards defining subcellular components, endomembrane organelles, energy organelles, endosymbiotic evidence, and cytoskeletal structures from Topics 2.1, 2.9, and 2.10.

Prokaryotes

Cells belonging to domains Bacteria and Archaea that lack a nucleus, have DNA concentrated in a nucleoid region, and are generally smaller in size than eukaryotes.

Eukaryotes

Cells including protists, fungi, animals, and plants that contain a membrane-bound nucleus housing DNA as well as other membrane-bound organelles.

Endomembrane Organelles

A classification of eukaryotic organelles that includes the nuclear envelope, endoplasmic reticulum, Golgi complex, lysosomes, vesicles/vacuoles, and plasma membrane.

Energy Organelles

A classification of eukaryotic organelles that includes mitochondria and chloroplasts.

Compartmentalization

The organization of cellular processes within membrane-bound organelles that allows different metabolic reactions to occur in separate locations, increasing surface area and preventing interfering reactions.

Nucleus

The eukaryotic organelle that contains chromosomes and is enclosed by a double-membrane nuclear envelope containing pores that regulate the entry and exit of materials.

Nucleolus

A dense region inside the nucleus where ribosomal RNA (rRNA) is synthesized and combined with proteins to form ribosome subunits.

Ribosomes

Cellular structures comprised of ribosomal RNA and protein that synthesize polypeptides by translating mRNA messages.

Free Ribosomes

Ribosomes located in the cytosol that synthesize proteins meant to function within the cytosol.

Bound Ribosomes

Ribosomes attached to the endoplasmic reticulum or nuclear envelope that synthesize proteins intended for membrane insertion or secretion from the cell via transport vesicles.

Rough Endoplasmic Reticulum

A network of membranous sacs studded with bound ribosomes that synthesizes membranes and compartmentalizes the cell to isolate proteins produced by bound ribosomes.

Smooth Endoplasmic Reticulum

A network of membranous sacs lacking ribosomes that synthesizes lipids, metabolizes carbohydrates, and detoxifies the cell.

Golgi Complex

An organelle consisting of flattened membranous sacs called cisternae that modifies, sorts, tags, and packages materials from the ER into transport vesicles for secretion or transport.

Cis Face

The receiving side of the Golgi complex that accepts transport vesicles carrying materials from the endoplasmic reticulum.

Trans Face

The shipping side of the Golgi complex that sends vesicles containing processed materials back out into the cytosol or to the plasma membrane for secretion via exocytosis.

Lysosomes

Membranous sacs of hydrolytic enzymes found in animal cells that hydrolyze macromolecules and recycle organic materials through autophagy.

Autophagy

The process by which lysosomes recycle a cell's own organic materials to allow the cell to renew itself.

Peroxisomes

Membrane-bound metabolic compartments that catalyze reactions producing hydrogen peroxide ($H_2O_2$) and then break down $H_2O_2$ into water using internal enzymes.

Food Vacuole

A type of vacuole formed via phagocytosis (cell eating) that merges with lysosomes for nutrient digestion.

Contractile Vacuole

A specialized vacuole that helps maintain appropriate water levels within certain cells.

Central Vacuole

A large vacuole found in plant cells containing inorganic ions and water that plays an important role in maintaining turgor pressure.

Endosymbiont Theory

The theory stating that an early eukaryotic cell engulfed a prokaryotic cell, which established an endosymbiont relationship and evolved into energy organelles like mitochondria and chloroplasts.

Cristae

Folds of the inner mitochondrial membrane that divide the mitochondrion into two internal compartments and increase total surface area for respiration.

Mitochondrial Matrix

The fluid compartment enclosed by the inner membrane of a mitochondrion containing enzymes, circular mitochondrial DNA, and ribosomes; serves as the site of the Krebs cycle.

Chloroplasts

Specialized photosynthetic organelles containing the green pigment chlorophyll, circular chloroplast DNA, ribosomes, and enzymes.

Thylakoids

Membranous sacs in chloroplasts organized into stacks called grana, where the light-dependent reactions of photosynthesis take place.

Stroma

The fluid surrounding thylakoids inside a chloroplast where the Calvin cycle occurs.

Microtubules

Hollow rod-like structures made of tubulin proteins that grow from centrosomes, serve as tracks for organelle movement, separate chromosomes during cell division, and power cilia and flagella.

Microfilaments

Thin solid rods composed of actin proteins that maintain cell shape, assist in muscle contraction alongside myosin, and form the contractile ring during animal cell division.

Intermediate Filaments

Fibrous, permanent structural proteins that maintain cell shape, anchor the nucleus and organelles, and form the nuclear lamina lining the nuclear envelope.