Campbell Biology concepts and connections
A tour of the cell
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| 841114569 | cell theory | The theory that all living things are composed of cells and that all cells come from other cells. | |
| 841114570 | cell wall | A protective layer external to the plasma membrane in plant cells, bacteria, fungi, and some protists; protects the cell and helps maintain its shape. | |
| 841114571 | cellular metabolism | The chemical activities of cells. | |
| 841114572 | central vacuole | A membrane-enclosed sac occupying most of the interior of a mature plant cell, having diverse roles in reproduction, growth, and development. | |
| 841114573 | centriole | A structure in an animal cell composed of cylinders of microtubule triplets arranged in a 9 and 0 pattern. An animal usually has a centrosome with a pair of centrioles involved in cell division. | |
| 841114574 | chloroplast | An organelle found in plants and photosynthetic protists that absorbs sunlight and uses it to drive the synthesis of organic molecules (sugars) from carbon dioxide and water. | |
| 841114575 | chromatin | The complex of DNA and proteins that constitutes eukaryotic chromosomes; often used to refer to the diffuse, very extended form taken by chromosomes when a cell is not dividing. | |
| 841114576 | chromosome | A threadlike, gene-carrying structure found in the nucleus of a eukaryotic cell and most visible during mitosis and meiosis; also, the main gene-carrying structure of a prokaryotic cell. Chromosomes consist of chromatin, a combination of DNA and protein. | |
| 841114577 | crista | An infolding of the inner membrane of a mitochondrion in which is embedded the electron transport chain and the enzyme catalyzing the synthesis of ATP. | |
| 841114578 | cytoplasm | Everything inside a cell between the plasma membrane and the nucleus; consists of a semifluid medium and organelles. | |
| 841114579 | cytoskeleton | A network of protein fibers in the cytoplasm of a eukaryotic cell; includes microfilaments, intermediate filaments, and microtubules. | |
| 841114580 | electron microscope (EM) | An instrument that focuses an electron beam through, or onto the surface of, a specimen. An electron microscope achieves a hundredfold greater resolution than a light microscope. | |
| 841114581 | endomembrane system | A network of membranes inside and around a eukaryotic cell, related either through direct physical contact or by the transfer of membranous vesicles. | |
| 841114582 | endoplasmic reticulum (ER) | An extensive membranous network in a eukaryotic cell, continuous with the outer nuclear membrane and composed of ribosome-studded (rough) and ribosome-free (smooth) regions. | |
| 841114583 | endosymbiosis | A process by which the mitochondria and chloroplasts of eukaryotic cells probably evolved from symbiotic associations between small prokaryotic cells living inside larger cells. | |
| 841114584 | eukaryotic cell | A type of cell that has a membrane-enclosed nucleus and other membrane-enclosed organelles. All organisms except bacteria and archaea are composed of eukaryotic cells. | |
| 841114585 | extracellular matrix (ECM) | A substance in which the cells of an animal tissue are embedded; consists of protein and polysaccharides. | |
| 841114586 | flagellum | A long cellular appendage specialized for locomotion. The flagella of prokaryotes and eukaryotes differ in both structure and function. Like cilia, eukaryotic flagella have a 9 + 2 arrangement of microtubules covered by the cell's plasma membrane. | |
| 841114587 | glycoprotein | A macromolecule consisting of one or more polypeptides linked to short chains of sugars. | |
| 841114588 | Golgi apparatus | An organelle in eukaryotic cells consisting of stacks of membranous sacs that modify, store, and ship products of the endoplasmic reticulum. | |
| 841114589 | granum | A stack of hollow disks formed of thylakoid membrane in a chloroplast. Grana are the sites where light energy is trapped by chlorophyll and converted to chemical energy during the light reactions of photosynthesis. | |
| 841114590 | intermediate filament | An intermediate-sized protein fiber that is one of the three main kinds of fibers making up the cytoskeleton of eukaryotic cells. Intermediate filaments are ropelike, made of fibrous proteins. | |
| 841114591 | light microscope (LM) | An optical instrument with lenses that refract (bend) visible light to magnify images and project them into a viewer's eye or onto photographic film. | |
| 841114592 | lysosome | A digestive organelle in eukaryotic cells; contains hydrolytic enzymes that digest the cell's food and wastes. | |
| 841114593 | microfilament | The thinnest of the three main kinds of protein fibers making up the cytoskeleton of a eukaryotic cell; a solid, helical rod composed of the globular protein actin. | |
| 841114594 | micrograph | A photograph taken through a microscope. | |
| 841114595 | microtubule | The thickest of the three main kinds of fibers making up the cytoskeleton of a eukaryotic cell; a straight, hollow tube made of globular proteins called tubulins. Microtubules form the basis of the structure and movement of cilia and flagella. | |
| 841114596 | mitochondrial matrix | The fluid contained within the inner membrane of a mitochondrion. | |
| 841114597 | mitochondrion | An organelle in eukaryotic cells where cellular respiration occurs. Enclosed by two concentric membranes, it is where most of the cell's ATP is made. | |
| 841114598 | nuclear envelope | A double membrane, perforated with pores, which encloses the nucleus and separates it from the rest of the eukaryotic cell. | |
| 841114599 | nucleoid | A dense region of DNA in a prokaryotic cell. | |
| 841114600 | nucleolus | A structure within the nucleus of a eukaryotic cell where ribosomal RNA is made and assembled with proteins imported from the cytoplasm to make ribosomal subunits. | |
| 841114601 | nucleus | (1) An atom's central core, containing protons and neutrons. (2) The genetic control center of a eukaryotic cell. | |
| 841114602 | organelle | A membrane-enclosed structure with a specialized function within a cell. | |
| 841114603 | peroxisome | An organelle containing enzymes that transfer hydrogen from various substrates to oxygen, producing and then degrading hydrogen peroxide. | |
| 841114604 | plasma membrane | The membrane that sets a cell off from its surroundings and acts as a selective barrier to the passage of ions and molecules into and out of the cell; consists of a phospholipid bilayer in which are embedded molecules of protein and cholesterol. | |
| 841114605 | plasmodesma | An open channel in a plant cell wall through which strands of cytoplasm connect from adjacent cells. | |
| 841114606 | prokaryotic cell | A type of cell lacking a membrane-enclosed nucleus and other membrane-enclosed organelles; found only in the domains Bacteria and Archaea. | |
| 841114607 | ribosome | A cell structure consisting of RNA and protein organized into two subunits and functioning as the site of protein synthesis in the cytoplasm. The ribosomal subunits are constructed in the nucleolus. | |
| 841114608 | rough ER | A network of interconnected membranous sacs in a eukaryotic cell's cytoplasm. Rough ER membranes are studded with ribosomes that make membrane proteins and secretory proteins. | |
| 841114609 | scanning electron microscope (SEM) | A microscope that uses an electron beam to study the surface architecture of a cell or other specimen. | |
| 841114610 | stroma | The fluid of the chloroplast surrounding the thylakoid membrane; involved in the synthesis of organic molecules from carbon dioxide and water; Sugars are made in the stroma by the enzymes of the Calvin cycle. | |
| 841114611 | thylakoid | One of a number of disk-shaped membranous sacs inside a chloroplast. Thylakoid membranes contain chlorophyll and the enzymes of the light reactions of photosynthesis. A stack of thylakoids is called a granum. | |
| 841114612 | transmission electron microscope | A microscope that uses an electron beam to study the internal structure of thinly sectioned specimens. | |
| 841114613 | Transport vesicle | A tiny membranous sac in a cell's cytoplasm carrying molecules produced by the cell. The vesicle buds from the endoplasmic reticulum or Golgi and eventually fuses with another membranous organelle or the plasma membrane, releasing its contents. | |
| 841114614 | Vacuole | A membrane-enclosed sac that is part of the endomembrane system of a eukaryotic cell, having diverse functions. | |
| 841114615 | Vesicle | A sac made of membrane in the cytoplasm of a eukaryotic cell. | |
| 841114616 | Reverse Transcriptase | Makes RNA into DNA |
