| 8292133786 | Cells | The simplest collection of matter that can be alive. |  | 0 |
| 8292133789 | Organelles | The membrane-enclosed structures within eukaryotic cells. |  | 1 |
| 8292133793 | Cytology | The study of cell structure. |  | 2 |
| 8292133794 | Biochemistry | The study of the chemical processes (metabolism) of cells. |  | 3 |
| 8292133795 | Metabolism | The chemical processes of cells. |  | 4 |
| 8292133796 | Cell Fractionation | A useful technique for studying cell structure and function which takes cells apart and separated major organelles and other sub cellular structures from one another, enabling researchers to prepare specific cell components in bulk and identify their functions, a task not usually possible with intact cells. |  | 5 |
| 8292133797 | Centrifuge | The piece of equipment used in the task of cell fractionation by spinning test tubes holding mixtures of disrupted cells at a series of increasing speeds. At each speed, the resulting force causes a subset of the cell components to settle to the bottom of the tube, forming a pellet. At lower speeds, the pellet consists of larger components, and higher speeds result in a pellet with smaller components. |  | 6 |
| 8292133809 | Nucleus | One of two cellular components involved in the genetic control of the cell, housing most of the cell's DNA. Contains most of the genes in the eukaryotic cell. |  | 7 |
| 8292133810 | Ribosomes | One of two cellular components involved in the genetic control of the cell, which are complexes of ribosomal RNA and protein that uses information from the DNA to make proteins. They are not membrane bounded and thus are not considered organelles. |  | 8 |
| 8292133811 | Nuclear Envelope | The double membrane made of two lipid bilayer membranes associated with proteins that encloses the nucleus, separating its contents from the cytoplasm. |  | 9 |
| 8292133812 | Pore Complex | An intricate protein structure that lines each pore on the nuclear envelope, playing an important role in the cell by regulating the entry and exit of proteins and RNAs, as well as large complexes of macromolecules. |  | 10 |
| 8292133813 | Nuclear Lamina | The netlike array of protein filaments that lines the nuclear side of the envelope (except at the pores), maintaining the shape of the nucleus by mechanically supporting the nuclear envelope. |  | 11 |
| 8292133814 | Nuclear Matrix | A framework of protein fibers extending throughout a cell's nuclear interior. |  | 12 |
| 8292133815 | Chromosomes | The discrete units DNA is organized into within the nucleus, structures that carry the genetic information of the cell by containing one long DNA molecule associated with many proteins. |  | 13 |
| 8292133816 | Chromatin | The complex of DNA and proteins making up chromosomes. |  | 14 |
| 8292133817 | Nucleolus | A prominent structure within the nondividing nucleus, which appears through the electron microscope as a mass of densely stained granules and fibers adjoining part of the chromatin. |  | 15 |
| 8292133818 | Ribosomal RNA (rRNA) | A type of RNA that is synthesized from instructions in the DNA within the nucleolus of a cell. |  | 16 |
| 8292133819 | Messenger RNA (mRNA) | The protein whose synthesis is directed by the nucleus according to instructions provided by the DNA before being transported to the cytoplasm via nuclear pores. Once reaching the cytoplasm, its genetic message is translated by ribosomes into the primary structure of a specific polypeptide. | | 17 |
| 8292133820 | Free Ribosomes | Ribosomes that are suspended in cytosol, whose proteins tend to function within the cytosol. |  | 18 |
| 8292133821 | Bound Ribosomes | Ribosomes that are attached to the outside of the endoplasmic reticulum or nuclear envelope, whose proteins are generally destined for insertion into membranes, for packaging within certain organelles such as lysosomes, or for export from the cell (secretion). |  | 19 |
| 8292133822 | The Endomembrane System | The collection of many different membranes of the eukaryotic cell, including the nuclear envelope, the endoplasmic reticulum, the Golgi apparatus, lysosomes, various kinds of vesicles and vacuoles, and the plasma membrane. This system carries out a variety of tasks in the cell, including synthesis of proteins, transport of proteins into membranes and organelles or out of the cell, metabolism and movement of lipids, and detoxification of poisons. |  | 20 |
| 8292133823 | Vesciles | Sacs made of membrane that unite the endomembrane system through the transfer of membrane segments. |  | 21 |
| 8292133824 | The Endoplasmic Reticulum (ER) | Such an extensive network of membranes that it accounts for more than half the total membrane in many eukaryotic cells, consisting of a network of membranous tubules and sacs called cisternae. |  | 22 |
| 8292133825 | Cisternae | The network of membranous tubules and sacs found in the endoplasmic reticulum, an the flattened membranous sacs the Golgi apparatus consists of. |  | 23 |
| 8292133826 | The Endoplasmic Reticulum (ER) Lumen (Cisternal Space) | The internal compartment of the endoplasmic reticulum, separated from the cytosol in a cell by the endoplasmic reticulum's membrane. |  | 24 |
| 8292133827 | Smooth Endoplasmic Reticulum (ER) | One distinct region of the endoplasmic reticulum, so named because its outer surface lacks ribosomes, functioning in diverse metabolic processes that vary with cell type, including synthesis of lipids, metabolism of carbohydrates, detoxification of drugs and poisons, and storage of calcium ions. |  | 25 |
| 8292133828 | Rough Endoplasmic Reticulum (ER) | One distinct region of the endoplasmic reticulum, studded with ribosomes on the outer surface of the membrane. The region which many proteins secreted by proteins produced by ribosomes attach to. |  | 26 |
| 8292133829 | Glycoproteins | The common type of secretory proteins that have carbohydrates covalently bonded to them. |  | 27 |
| 8292133830 | Transport Vesicles | Vesicles in transit from one part of the cell to another. |  | 28 |
| 8292133831 | The Golgi Apparatus | The region many transport vesicles travel to after leaving the endoplasmic reticulum that is especially extensive in cells specialized for secretion. Here, products of the endoplasmic reticulum, such as proteins, are modified and then sent to other destinations. |  | 29 |
| 8292133832 | The Cis Golgi Side | The receiving department of the Golgi apparatus, usually located near the endoplasmic reticulum. Transport vesicles move material from the endoplasmic reticulum to the Golgi apparatus. A vesicle that buds from the endoplasmic reticulum can add its membrane and the contents of its lumen to it by fusing with a Golgi membrane. |  | 30 |
| 8292133833 | The Trans Golgi Side | The shipping department of the Golgi apparatus that gives rise to vesicles that pinch off and travel to other sites. | | 31 |
| 8292133834 | Cisternal Maturation Model | The model that states the cisternae of the Golgi actually progress forward from the cis to the trans face, carrying and modifying their cargo as they move. |  | 32 |
| 8292133835 | Lysosome | A membranous sac of hydrolytic enzymes that many eukaryotic cells use to digest (hydrolyze) macromolecules. |  | 33 |
| 8292133836 | Phagocytosis | The process by which amoebas and many other unicellular eukaryotes eat by engulfing smaller organisms or food particles. The process also occurs in some human cells, such as the macrophage, a type of white blood cell that helps defend the body by engulfing and destroying bacteria and other invaders. |  | 34 |
| 8292133837 | The Food Vacuole | The vacuole formed by phagocytosis that fuses with a lysosome, whose enzymes digest the food. |  | 35 |
| 8292133838 | Autophagy | The process by which lysosomes user their hydrolytic enzymes to recycle the cell's own organic material, during which a damaged organelle or small amount of cytosol becomes surrounded by a double membrane (of unknown origin), and a lysosome fuses with the outer membrane of this vesicle. The lysosomal enzymes dismantle the enclosed material, and the resulting small organic compounds are released to the cytosol for reuse. With the help of lysosomes, the cell continually renews itself. |  | 36 |
| 8292133839 | Vacuoles | Large vesicles derived from the endoplasmic reticulum and Golgi apparatus and are an integral part of a cell's endomembrane system, performing a variety of functions in different kinds of cells. |  | 37 |
| 8292133840 | Contractile Vacuoles | The type of vacuole that manny unicellular eukaryotes living in fresh water have, that pump excess water out of the cell, thereby maintaining a suitable concentration of ions and molecules inside the cell. |  | 38 |
| 8292133841 | Central Vacuole | The vacuole that mature plant cells generally contain, which develop by the coalescence of smaller vacuoles. The solution inside, called the cell sap, is the plant cell's main repository of inorganic ions, including potassium and chloride. It plays a major role in the growth of plant cells, which enlarge as the vacuole absorbs water, enable the cell to become larger with a minimal investment in new cytoplasm. |  | 39 |
| 8292133842 | Mitochondria | The sites of cellular respiration, the metabolic process that uses oxygen to drive the generation of ATP by extracting energy from sugars, fats, and other fuels. They are found in nearly all eukaryotic cells, including those of plants, animals, fungi, and most unicellular eukaryotes. |  | 40 |
| 8292133843 | Cellular Respiration | The metabolic process that uses oxygen to drive the generation of ATP by extracting energy from sugars, fats, and other fuels. |  | 41 |
| 8292133844 | Chloroplasts | The sites of photosynthesis found in plants and algae, which contain the green pigment chlorophyll, along with enzymes and other molecules that function in the photosynthetic production of sugar. |  | 42 |
| 8292133845 | Photosynthesis | The process in chloroplasts that converts solar energy to chemical energy by absorbing sunlight and using it to drive the synthesis of organic compounds such as sugars from carbon dioxide and water. |  | 43 |
| 8292133846 | Endosymbiont Theory | The theory that is suggested by the similarities displayed between mitochondria and chloroplasts and bacteria. This theory states that an early ancestor of eukaryotic cells engulfed an oxygen-using non-photosynthetic prokaryotic cell. Eventually, the engulfed cell formed a relationship with the host cell in which it was enclosed, becoming an endosymbiont (a cell living within another cell). Indeed, over the course of evolution, the host cell and its endosymbiont merged into a single organism, a eukaryotic cell with a mitochondrion. At least one of these cells may have then taken up a photosynthetic prokaryote, becoming the ancestor of eukaryotic cells that contain chloroplasts. |  | 44 |
| 8292133847 | Endosymbiont | A cell living within another cell. |  | 45 |
| 8292133848 | Cristae | The infoldings that convolute the inner membrane of mitochondria. |  | 46 |
| 8292133849 | The Intermembrane Space | The narrow region between the inner and outer membranes of mitochondria. |  | 47 |
| 8292133850 | The Mitochondrial Matrix | The compartment enclosed by the inner membrane of mitochondria, containing many different enzymes as well as the mitochondrial DNA and ribosomes. These enzymes catalyze some of the steps of cellular respiration. |  | 48 |
| 8292133851 | Thylakoids | The flattened, interconnected membranous sac system found inside the chloroplast. In some regions, they are stacked like poker chips; each stack is called a granum. |  | 49 |
| 8292133852 | Granum | A stack of thylakoids. |  | 50 |
| 8292133853 | Stroma | The fluid outside thylakoids, which contains the chloroplast DNA and ribosomes as well as enzymes. |  | 51 |
| 8292133854 | Plastids | The family of closely related plant organelles of which the chloroplast is a specialized member. |  | 52 |
| 8292133855 | Peroxisome | A specialized metabolic compartment bounded by a single member,e containing enzymes that remove hydrogen atoms from various substrates that transfer them to oxygen, producing hydrogen peroxide as a by-product. How they are related to other organelles is still an open question. |  | 53 |
| 8292133856 | Glyoxysomes | Specialized peroxisomes found in fat-storing tissues of plant seeds. These organelles contain enzymes that initiate the conversion of fatty acids to sugar, which the emerging seedling uses as a source of energy and carbon until it can produce its own sugar by photosynthesis. |  | 54 |
| 8292133857 | The Cytoskeleton | A network of fibers extending throughout the cytoplasm. |  | 55 |
| 8292133858 | Cell Motility | The changes in cell location and the movements of cell parts. |  | 56 |
| 8292133859 | Motor Proteins | The proteins required by cell motility for the cytoskeleton to interact with. Vesicles and other organelles often use their "feet" to "walk" to destinations along a track provided by the cytoskeleton. |  | 57 |
| 8292133860 | Microtubules (Tubulin Polymers) | The thickest of the three types of fibers that make up the cytoskeleton. They are hollow tubes 25 nanometers in size (with 15-nanometer lumens) made of tubulin, a dimer consisting of alpha-tubulin and beta-tubulin. Their main functions are the maintenance of cell shape (compression-resisting "girders"), cell motility (as in cilia or flagella), chromosome movements in cell division, and organelle movements. |  | 58 |
| 8292133861 | Microfilaments (Actin Filaments) | The thinnest of the three types of fibers that make up the cytoskeleton. They are made of two intertwined strands of actin and are 7 nanometers in diameter. Their main functions are the maintenance of cell shape (tension-bearing elements), changes in cell shape, muscle contraction, cytoplasmic streaming in plant cells, cell motility (as in amoeboid movement), and division of animal cells. |  | 59 |
| 8292133862 | Intermediate Filaments | The fibers with diameters in a middle range among those that make up the cytoskeleton. They are fibrous proteins coiled into cables of 8-12 nanometers in diameter, made of one of several different proteins (such as keratins). Their main functions are the maintenance of cell-shape (tension-bearing elements), the anchorage of nucleus and certain other organelles, and the formation of nuclear lamina. |  | 60 |
| 8292133863 | Dimer | A molecule made up of two subunits. |  | 61 |
| 8292133864 | Centrosome | The region often located near the nucleus from which microtubules grow out from in animal cells. |  | 62 |
| 8292133865 | Centrioles | Pairs of nine sets of triplet microtubules arranged in a ring found within a centrosome. |  | 63 |
| 8292133866 | Flagella | The longer microtubule-containing extensions that project from some cells. Usually limited to just one or a few per cell when in motile capacity. They have an undulating motion like the tail of a fish. |  | 64 |
| 8292133867 | Cilia | The shorter microtubule-containing extensions that project from some cells. Usually occur in large numbers on the cell surface when in motile capacity. They work more like oars, with alternating power and recovery strokes. | | 65 |
| 8292133868 | The 9 + 2 Pattern | The arrangement in which nine doublets of microtubules are arranged in a ring, with two single microtubules in its center, found in nearly all eukaryotic flagella and motile cilia. |  | 66 |
| 8292133869 | The Basal Body | Structures similar to centrioles, with microtubule triplets in a 9 + 0 pattern, which anchor the microtubule assembly of a cilium or flagellum. |  | 67 |
| 8292133870 | Dyneins | Large motor proteins involved in bending that are attached along each outer microtubule doublet. A typical protein of this type has two "feet" that "walk" along the microtubule of the adjacent doublet, using ATP for energy. |  | 68 |
| 8292133871 | Actin | The globular proteins that microfilaments are built from. |  | 69 |
| 8292133872 | The Cytoplasmic Cortex | The outer layer of a cell, has a semisolid consistency of a gel. |  | 70 |
| 8292133873 | Myosin | The protein that makes up thicker filaments that interact with thousands of actin filaments to cause contraction of muscle cells. | | 71 |
| 8292133874 | Pseudopodia | The cellular extensions cell's extend in order to crawl along a surface. |  | 72 |
| 8292133875 | Cytoplasmic Streaming | A process of flow of cytoplasm within cells that is supported by actin-myosin interactions. |  | 73 |
| 8292133876 | The Cell Wall | An extracellular structure of plant cells that distinguishes them from animal cells, protecting the plant cell, painting its shape, and preventing excessive uptake of water. |  | 74 |
| 8292133877 | Primary Cell Wall | The relatively thin and flexible wall a young plant secretes first. |  | 75 |
| 8292133878 | Middle Lamella | The thin layer rich in sticky polysaccharides called pectins between primary walls of adjacent cells, gluing adjacent cells together. |  | 76 |
| 8292133879 | Secondary Cell Wall | The wall other cells add between the plasma membrane and the primary wall. Often deposited in several laminated layers, it has a strong and durable matrix that affords the cell protection and support. | | 77 |
| 8292133880 | The Extracellular Matrix (ECM) | An elaborate system found between animal cells whose main ingredients are glycoproteins and other carbohydrate-containing molecules secreted by cells. |  | 78 |
| 8292133881 | Collagen | The most abundant glycoprotein in the extracellular matrix, which forms strong fibers outside cells. |  | 79 |
| 8292133882 | Proteoglycans | Molecules that consist of a small core protein with many carbohydrate chains covalently attached, weaving a network secreted by cells. They may be up to 95% carbohydrate. |  | 80 |
| 8292133883 | Fibronectin | A glycoprotein that attaches some cells to the extracellular matrix. |  | 81 |
| 8292133884 | Integrins | Cell-surface receptor proteins, built into and spanning membranes and binding on their cytoplasmic side to associated proteins attached to microfilaments on the cytoskeleton. |  | 82 |
| 8292133885 | Plasmodesmata | The channels cell walls are perforated with that connect them together. The cytosol that passes through them joins the internal chemical environment of adjacent cells, unifying most of the plant into one living continuum. |  | 83 |
| 8292133886 | Tight Junctions | A type of cell junction in animal cells in which the plasma membranes of neighboring cels are very tightly pressed against each other, bound together by specific proteins. Forming continuous seals around the cells, they establish a a barrier that prevents leakage of extracellular fluid across a layer of epithelial tissue. For example, they unit our skin cells to make watertight flesh. |  | 84 |
| 8292133887 | Desmosomes (Anchoring Junctions) | A type of cell junction in animal cells that functions like rivets, fastening cells together into strong sheets. Intermediate filaments made of sturdy keratin proteins anchor them in the cytoplasm. They attach muscle cells to each other in a muscle. | | 85 |
| 8292133888 | Gap Junctions (Communicating Junctions) | A type of cell junction in animal cells that provides cytoplasmic channels from one cell to an adjacent cell (and in this way are similar in function to the plasmodesmata in plants). They consist of membrane proteins that surround a pore through which ions, sugars, amino acids, and other small molecules may pass. They are necessary for communication between cells in many types of tissues, such as heart muscle, and in animal embryos. | | 86 |
