Organelles (Campbell Biology, TWELFTH EDITION)

Vocabulary flashcards covering major organelles, cellular structures, and related concepts from the lecture notes.

Cell theory

Cells are the basic unit of life; unicellular organisms perform all functions within a single cell; multicellular organisms have specialized cells but share the same basic cell structure.

Prokaryote

A simple, unicellular organism that lacks a discrete nucleus; genetic material is within a single chromosome.

Eukaryote

Organisms with cells that contain a nucleus bounded by a nuclear envelope and membrane-bound organelles; generally larger than prokaryotes.

Plasma membrane

The boundary membrane of a cell that acts as a selective barrier, regulating the cell’s chemical composition.

DNA

Stores genetic information to pass to the next generation.

Ribosome

A particle composed of rRNA and ~80 proteins that synthesizes proteins by translating mRNA.

Cytoplasm (cytosol)

The internal fluid where biochemical processes occur in the cell.

Nucleus

The most conspicuous organelle that houses the cell’s genetic material; contains the nucleolus, chromatin, and is enclosed by the nuclear envelope.

Nucleolus

Region inside the nucleus active in synthesis of rRNA and ribosome assembly.

Nuclear envelope

Double membrane enclosing the nucleus, separating it from the cytoplasm.

Chromatin

DNA-protein complex that makes up the eukaryotic chromosome.

Chromosome

Structure of DNA and protein containing the organism’s genetic information.

Nuclear pore complex

Multi-protein channel in the nuclear envelope that regulates movement of proteins, RNA, and ribosomal subunits between the nucleus and cytoplasm.

Nuclear lamina

A network of protein filaments on the inner side of the nuclear envelope that maintains nuclear shape.

Endomembrane system

A group of membranes and organelles that divide the cell into functional compartments; components are continuous or connected via transfer vesicles and regulate protein traffic.

Endoplasmic reticulum (ER)

A biosynthetic factory: a network of membranous tubules and sacs where lipids are made and membrane-bound/secretory proteins are synthesized; continuous with the nuclear envelope.

Rough ER

ER region studded with ribosomes; synthesizes membrane-bound and secretory proteins; proteins are transported by vesicles.

Smooth ER

ER region lacking ribosomes; involved in lipid synthesis, carbohydrate metabolism, and detoxification.

Golgi apparatus

Flattened membrane-bound sacs (cisternae) that modify, sort, and package proteins and lipids from the ER.

cis face

Receiving side of the Golgi where vesicles from the ER fuse.

trans face

Shipping side of the Golgi where products are dispatched to final destinations.

Cisternae

Flattened membrane-bound sacs that make up the Golgi apparatus.

Transport vesicles

Vesicles that move cargo between the ER and Golgi and to other destinations; can transport materials backward or forward.

Lysosome

Membranous sac containing hydrolytic enzymes; digests macromolecules and recycles components; produced by the ER and Golgi; not present in plants.

Autophagy

Process by which lysosomes digest the cell’s own organelles and macromolecules.

Phagocytosis

Process by which cells ingest large particles; lysosomes participate in digestion of the captured material.

Lysosomal pH

Acidic pH (~5) inside lysosomes that keeps enzymes active; rupture releases enzymes that can be harmful if not contained.

Vacuole

Membrane-bound sacs with varied functions; central vacuoles store water and metabolites in plants, food vacuoles aid in digestion, and contractile vacuoles manage water in some protists.

Tonoplast

Membrane surrounding the central vacuole in plant cells.

Mitochondrion

Organelle that produces ATP via aerobic respiration; double membrane with inner folds called cristae, creating intermembrane space and matrix.

Intermembrane space

Space between the inner and outer mitochondrial membranes.

Mitochondrial matrix

Space inside the inner membrane containing enzymes for respiration.

Chloroplast

Organelle in photosynthetic cells that captures light energy; contains chlorophyll; part of the plastid family.

Thylakoids

Membranous sacs inside chloroplasts where light reactions occur.

Stroma

Internal fluid of the chloroplast surrounding the thylakoid membranes.

Plastids

Family of organelles including chloroplasts; involved in storage and photosynthesis.

Chlorophyll

Green pigment in chloroplasts that participates in photosynthesis.

Peroxisome

Membrane-bound organelle using oxygen to oxidize organic molecules; produces hydrogen peroxide and contains enzymes to degrade H2O2; detoxifies alcohols and fatty acids.

Plasmalogens

Antioxidant phospholipids produced in peroxisomes; support membrane structure and regulate signaling.

Endosymbiont theory

Prokaryotic cells gave rise to mitochondria and chloroplasts in eukaryotic cells; organelles have double membranes, circular genomes, and own ribosomes; likely originated from engulfed bacteria.