BIOL 101: Vocabulary Flashcards on Cellular Structure and Organelles

A comprehensive set of vocabulary flashcards covering cellular structure, organelles, and related concepts from the BIOL 101 lecture notes.

Cell Theory

The idea that all organisms are made of cells, cells are the basic unit of life, new cells arise from pre-existing cells, and all cells share a common descent from the first living cells.

Prokaryotic cell

A cell without a true nucleus or membrane-bound organelles; includes Bacteria and Archaea; DNA located in the nucleoid and usually unicellular.

Eukaryotic cell

A cell with a membrane-bound nucleus and organelles; plants, animals, fungi, and protists; may be unicellular or multicellular.

Endomembrane system

A network of membranes (nuclear envelope, ER, Golgi apparatus, lysosomes, vacuoles, plasma membrane) connected directly or via vesicles to regulate protein traffic and metabolism.

Nucleus

Membrane-bound organelle that houses the cell’s DNA and regulates gene expression; contains the nucleolus.

Nucleolus

A region within the nucleus where ribosomal RNA (rRNA) synthesis occurs.

Nuclear envelope

Double-membrane barrier surrounding the nucleus that controls traffic between the nucleus and cytoplasm.

Nuclear pore

Protein complexes that regulate transport of molecules between the nucleus and cytoplasm.

Ribosome

Ribonucleoprotein particles that synthesize proteins; can be free in cytoplasm or attached to the rough endoplasmic reticulum; composed of rRNA and proteins.

Endoplasmic reticulum (ER)

A network of membranous sacs; Rough ER has bound ribosomes for protein synthesis; Smooth ER lacks ribosomes and often functions in lipid synthesis and detoxification.

Rough ER

ER with attached ribosomes; synthesizes proteins destined for secretion, lysosomes, or the plasma membrane.

Golgi apparatus

Stack of flattened membranes that processes, packages, and ships proteins and lipids; has cis (receiving) and trans (shipping) faces and uses vesicles for transport.

Lysosome

Membrane-bound digestive vesicle containing hydrolytic enzymes that break down macromolecules and recycle old organelles or engulfed material.

Peroxisome

Microbody containing enzymes for fatty acid oxidation; produces and detoxifies hydrogen peroxide via catalase.

Vacuole

Membrane-bound vesicle with various roles; central vacuole in plants stores water and maintains turgor; other vacuoles store substances or digest.

Central vacuole

Large plant cell vacuole that stores water, maintains turgor pressure, and contains enzymes and nutrients.

Mitochondrion

Organelle responsible for energy production through cellular respiration; double membrane with cristae and matrix; contains its own DNA.

Chloroplast

Plastid in plants and some algae that carries out photosynthesis; contains chlorophyll, two membranes, and its own DNA; has thylakoids and grana.

Thylakoid

Flattened, membrane-bound sacs inside chloroplasts where light-dependent reactions occur.

Grana

Stacks of thylakoids within chloroplasts that maximize light capture for photosynthesis.

Endosymbiosis theory

Hypothesis that mitochondria and chloroplasts originated as free-living bacteria engulfed by an ancestral eukaryotic cell.

Cytoskeleton

Network of protein fibers (actin, tubules, intermediate filaments) that supports cell shape, anchors organelles, and enables movement.

Actin filament (microfilament)

Thin cytoskeletal fibers involved in cell movement, shape changes, and muscle contraction.

Microtubule

Thick, hollow tubes made of tubulin that organize cell shape, chromosome movement, and intracellular transport.

Intermediate filament

Cytoskeletal fibers that provide mechanical strength and stability; more stable than actin filaments and microtubules.

Centrosome

Microtubule-organizing center in many animal cells that nucleates microtubule assembly; often contains centrioles.

Centriole

Cylindrical structure within the centrosome; essential for organizing microtubules in animal cell division; plants/fungi often lack.

Flagellum and cilium

Projections that enable cell movement; display a 9+2 microtubule arrangement; flagella are long, few; cilia are short and numerous.

Cell wall

Rigid outer layer in plants (cellulose), fungi (chitin), and many bacteria (peptidoglycan) that provides support and protection.

Bacterial cell wall (peptidoglycan)

Rigid layer outside the bacterial plasma membrane composed of peptidoglycan; crucial for shape and antibiotic targeting.

Capsule (glycocalyx)

A gelatinous outer layer in some bacteria that protects against desiccation and immune attack.

Fimbriae

Hairlike projections aiding bacterial adhesion to surfaces.

Pili

Longer than fimbriae; enable conjugation and attachment to surfaces.

Nucleoid

Region in prokaryotes where the circular DNA is located; not enclosed by a membrane.

Plasmodesmata

Channels through plant cell walls that connect cytoplasm of adjacent cells; allow transport and communication between plant cells.

Plasma membrane

Phospholipid bilayer with embedded proteins and carbohydrate side chains; controls movement of substances into and out of the cell.

Cytoplasm

Fluid interior of the cell (cytosol) excluding the nucleus; site of many metabolic activities.

Chromosome

DNA-protein complex that carries genetic information; eukaryotes have multiple linear chromosomes.

Chromatin

Complex of DNA and proteins (histones) that makes up chromosomes; condenses during cell division.

Extracellular matrix (ECM)

Network of glycoproteins outside animal cells (e.g., collagen) that supports cells and connects to the cytoskeleton via integrins; influences cell behavior.

MHC proteins

Major histocompatibility complex proteins on cell surfaces that help immune cells distinguish self from non-self.

Tight junction

Cell junction that seals neighboring cells together to prevent leakage of substances.

Desmosome

Adhesive junction that connects intermediate filaments of adjacent cells, providing mechanical strength.

Adherens junction

Junction that anchors cell membranes to the cytoskeleton, supporting tissue structure.

Gap junction

Direct cytoplasmic connections between adjacent cells allowing passage of ions and small molecules.

Plasmodesmata (reiterated)

Open channels in plant cell walls connecting cytoplasm of neighboring plant cells; coordinate transport and signaling.

Plasma membrane organization

Phospholipid bilayer with hydrophilic heads, hydrophobic tails, embedded proteins, and carbohydrate side chains that mediate transport and signaling.

SA:V ratio

Ratio of surface area to volume; smaller cells have a larger SA:V, enhancing diffusion and exchange with the environment.

Diffusion in cells

Passive transport process driven by concentration gradients, influenced by surface area, temperature, gradient magnitude, and distance.

Microscope resolution

Minimum distance between two points that can be distinguished as separate objects; naked eye resolution is about 100 μm.