Cell Structure & Cells in Culture - VOCABULARY Flashcards

Vocabulary-focused flashcards covering key terms from cell structure, membrane biology, organelles, autophagy, endomembrane system, and cells in culture.

Cell theory

The concept that all living things are made of cells; new cells arise from preexisting cells; the cell is the basic unit of life; modern versions include energy flow, DNA heredity, and similar chemical composition.

Prokaryotic cell

A cell lacking a defined nucleus and most organelles; DNA in a nucleoid region; usually unicellular and reproduces asexually.

Eukaryotic cell

A cell with a true nucleus and membrane-bound organelles; contains functional compartments.

Plasma membrane

The cell’s outer membrane of phospholipids and proteins; controls entry/exit and mediates signaling.

Phospholipid bilayer

Two-layer arrangement of phospholipids forming membranes; hydrophilic heads facing water and hydrophobic tails inward.

Amphiphilic

Molecule that has both hydrophilic (water-loving) and hydrophobic (water-fearing) regions.

Glycolipid

A lipid with carbohydrate chains on its extracellular surface; contributes to the glycocalyx.

Glycocalyx

Carbohydrate-rich layer on the cell surface formed by glycolipids and glycoproteins for protection and recognition.

Cholesterol (in membranes)

Sterol molecules interspersed in the bilayer that modulate membrane fluidity and stability.

Lipid raft

Small, dynamic, cholesterol- and sphingolipid-enriched membrane microdomains that organize signaling.

Membrane asymmetry

Different lipid compositions in the two leaflets of the bilayer (e.g., PC outer, PS inner); cholesterol roughly equal between leaflets.

Fluid mosaic model

Model describing a dynamic, fluid lipid bilayer with embedded proteins.

Integral membrane protein

Protein that spans the lipid bilayer; can form channels or transporters.

Peripheral membrane protein

Proteins attached to the membrane surface or to integral proteins; do not span the bilayer.

Receptor protein

Membrane protein with a binding site for a ligand to initiate cellular signaling.

Channel protein

Integral protein that forms a pore for ions/molecules; can be gated or ungated.

Carrier protein

Membrane protein that transports solutes via conformational changes; may use ATP.

Glycoprotein

Protein with carbohydrate chains; part of the glycocalyx and cell recognition.

CAMs (cell adhesion molecules)

Proteins such as integrins that mediate adhesion to other cells or ECM and help maintain cell shape.

Enzymatic proteins (membrane enzymes)

Proteins on the membrane that catalyze reactions, such as brush border enzymes.

Nucleus

Largest organelle containing DNA; enclosed by a double membrane with pores; contains chromatin and nucleolus.

Nucleolus

Nuclear substructure where ribosome subunits are produced.

Chromatin

DNA-protein complex in the nucleus; not condensed most of the time.

Chromosome

Condensed DNA-protein structure visible during cell division; carries genes.

Endomembrane system

Interconnected membranes (nuclear envelope, ER, Golgi, vesicles) that compartmentalize and traffic cellular materials.

Rough endoplasmic reticulum (RER)

ER studded with ribosomes; synthesizes and processes secretory and membrane proteins.

Smooth endoplasmic reticulum (SER)

ER without ribosomes; synthesizes lipids, metabolizes carbohydrates, detoxifies substances.

Golgi apparatus

Stacked membranes that modify, sort, and package proteins and lipids for secretion or internal use.

Lysosome

Acidic vesicle with hydrolytic enzymes that digest macromolecules and worn-out organelles; “suicide bags.”

Peroxisome

Vesicles containing enzymes for breaking down hydrogen peroxide and toxins.

Ribosome

RNA-protein complex that synthesizes proteins; free ribosomes make intracellular proteins; membrane-bound ribosomes synthesize secreted/membrane proteins.

Mitochondrion

Powerhouse of the cell; performs aerobic respiration to make ATP; double membrane with cristae and own DNA/ribosomes; evidence supports endosymbiosis.

Matrix (mitochondrion)

Space inside the inner mitochondrial membrane where enzymes of the citric acid cycle reside.

Autophagy

Lysosomal degradation pathway that recycles cytoplasmic components and damaged organelles; stress- or starvation-induced.

Autophagosome

Double-membrane vesicle that engulfs cytoplasmic material during autophagy.

Phagophore

Cup-shaped precursor membrane that grows to form the autophagosome.

Beclin1/PI3K

Proteins that regulate autophagosome membrane formation and stability.

Endoplasmic reticulum-Golgi transport

Vesicle-mediated trafficking from ER to Golgi for processing and sorting.

Central vacuole

Large plant cell organelle that stores water and maintains turgor pressure.

Chloroplast

Plant cell organelle that conducts photosynthesis and contains chlorophyll.

Plasmodesmata

Channels through plant cell walls that connect adjacent plant cells for transport and communication.

Nucleolus (repeat note)

Site of ribosome production within the nucleus.

Telomere

DNA-protein caps at chromosome ends; shorten with replication; maintained by telomerase.

Telomerase

Reverse transcriptase enzyme that extends telomeres, promoting cellular longevity in some cells.

Stem cell potency (totipotent, pluripotent, multipotent)

Totipotent: can generate all cell types and extraembryonic tissue; Pluripotent: many, but not all, cell types; Multipotent: limited to a lineage.

Primary cell culture

Cells derived directly from tissue; finite lifespan and heterogeneous.

Secondary culture

Derived from primary culture; more homogeneous; still finite.

Immortalized cell line

Cell culture line that can proliferate indefinitely due to transformation.

SV40 T antigen / EBV / HPV E6/E7

Viral genes used to transform cells and achieve immortalization.

CHO cells

Chinese hamster ovary cells; commonly used immortalized cell line in research.

Passage number

Number of times cells have been subcultured from the original culture.

Trypsin-EDTA

Detaches adherent cells by enzymatic digestion; EDTA chelates calcium to enhance trypsin activity.

PBS (phosphate-buffered saline)

Isotonic buffer used to wash cells; warmed to prevent shock.

Basal medium

Basal nutrient solution providing essential glucose, salts, and energy; often supplemented.

Serum

Fetal/bovine serum provides growth factors and nutrients to support growth.

Anchorage dependence

Requirement of many cells to attach to a surface to grow.

Contact inhibition

Regulation preventing overgrowth when cells contact neighbors.

Apoptosis

Programmed cell death; controlled cellular dismantling.