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| In reference to the Lipid Bilayer, two different heads, hydrophobic center and hydrophilic ends. Acts as cell membrane. |
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| Pigmented protein found in the plasma membrane of a salt-loving bacterium, (Halobacterium halobium; it pumps protons out of the cell in response to light) |
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| A layer of sugar residues, including the polysaccharide portions of proteoglycans and oligosaccharides attached to protein or lipid molecules, on the outer surface of a cell. |
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| Lipid molecule with a characteristic four-ringed steroid structure that is an important component of the plasma membranes of animal cells. |
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| Soapy substance used by biochemists to solubilize membrane proteins. |
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| Thin bimolecular sheet of mainly phospholipid molecules that forms the structural basis for all cell membranes. The two layers of lipid molecules are packed with their hydrophobic tails pointing inward and their hydrophilic heads outward, exposed to water. |
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| functionally specialized region in a cell membrane characterized by the presence of particular proteins. |
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| A protein associated with a lipid bilayer; can be either integral (transmembrane) or peripheral |
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| common phospholipid present in abundance in most biological membranes. |
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| Type of lipid molecule used to make biological membranes. Generally composed of two fatty acids linked through glycerol phosphate to one of a variety of polar groups. |
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| The membrane that surrounds a living cell. |
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| Describes an organic molecule that contains no double or triple carbon-carbon bonds. Not Unsaturated. |
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| Describes a molecule that contains one or more double or triple carbon-carbon bonds. |
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| Rapid, transient, self-propagating electrical signal in the plasma membrane of a cell such as a neuron or muscle. A nerve impulse |
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| Movement of a molecule across a membrane driven by ATP hydrolysis or another form of metabolic energy. |
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| Long Thin nerve cell process capable of rapidly conducting nerve impulses over long distances so as to deliver signals to other cells. |
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| An aqueous pore in a lipid membrane, with walls made of protein, through which selected ions or molecules can pass. |
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| Membrane transport protein that carriers out transport in which the transfer of one molecule depends on the simultaneous or sequential transfer of a second molecule. |
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| Driving force that casuses an ion to move across a membrane. Caused by differences in ion concentration and in electrical charge on either side of the membrane. |
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| Transmembrane protein or protein complex that forms a water-filled channel across the lipid bilayer through which specific inorganic ions can diffuse down their electrochemical gradients. |
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| An ion channel that opens when it binds a small molecule such as a neurotransmitter. |
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| Voltage Difference across a membrane due to a slight excess of positive ions on one side and of negative ions on the other. A typical membrane potential for an animal cell plasma membrane is -60mv, measured relative to the surrounding fluid. |
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| Membrane transport protein |
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| Any protein embedded in a membrane that serves as a carrier of ions or small molecules from one side to the other. |
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| transmembrane carrier protein, foundin the plasma membrane of most animal cells, that pumps Na+ out of and K+ into the cell, using the energy derived from ATP hydrolysis. |
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| Quantitative Expression that related the equilibrium ratio of contentrations of an ion on either side of a permeable membrane to the voltage difference across the membrane. |
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| The endings of an axon from which signals are sent to adjoining cells, usually at a synapse . |
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| Cell with long processes specialized to receive, conduct and transmit signals in the nervous system. |
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| Small signaling molecule secreted by a nerve cell at a chemical synapse to signal to the postsynaptic cell. Examples include acetylcholine, glutamate, GABA, and glycine. |
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| Net movement of water molecules across a semipermeable membrane driven by a difference in concentration of solute on either side. The membrane must be permeable to water but not to the solute molecules. |
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| Pressure that must be exerted on the low-solute concentration side of a semipermeable membrane to prevent the flow of water across the membrane as a result of osmosis. |
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| The movement of a small molecule or ion across a membrane due to a difference in the concentration of electrical charge. |
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| Technique in which the tip of a small glass electrode is sealed onto a patch of cell membrane, thereby making it possible to record the flow of current through individual ion channels in the patch. |
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| Membrane protein that allows the selective entry of specific ions into a cell and is opened by mechanical force. |
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| Specialized junction between a nerve cell and another cell(Nerve cell, Muscle cell, gland cell)across which the nerve impulse is transferred. In most synapses the signal is carried by a neurotransmitter, which is secreted b y the nerve cell and diffuses to the target cell. |
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| Small membrane-enclosed sac filled with neurotransmitter that releases its contents by exocytosis at a synapse. |
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| Membrane protein that transports ions or molecules across a cell membrane. |
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| Membrane protein that selectively allows ions such as Na+ to cross a membrane and is opened by changes in membrane potential. Found mainly in electrically excitable cells such as nerve and muscle. |
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| Structure in a photosystem that captures light. |
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| Membrane-associated enzyme complex that catalyzes the formation of ATP during oxidative phosphorylation and photosynthesis. Found in mitochondria, chloroplasts, and bacteria. |
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| Process by which green plants incorporate carbon atoms from atmospheric carbon dioxide into sugars. The second stage of photosynthesis. |
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| Mechanism in which a gradient of hydrogen ions across a membrane is used to drive an energy-requiring process, such as ATP production or the transport of a molecule across a membrane. |
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| Light-absorbing pigment that plays a central part in photosynthesis. |
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| Specialized organelle in algae and plants that contains chlorophyll and in which photosynthesis takes place. |
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| Cyclic photophosphorylation |
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| photosynthetic process incoling photosystem 1 only, by which chloroplasts can generate ATP without making NADPH. |
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| Colored, heme-containg protein that transfers electrons during cellular respiration and photosynthesis. |
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| Protein complex that receives electrons from cytochrome C, thus oxidizing it. It then donates the electrons to O2. |
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| A series of membrane-embedded electron carrier molecules along which electrons move from a higher to a lower energy level, as in oxidative phosphorylation. |
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| One of a family of electron transporters containing iron atoms linked to sulfur atoms and cysteine side chains; found in electron-transport chains such as those in mitochondria and chloroplasts. |
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| Most generally, a space within which something is formed. In cell biology, this word often refers to the large internal compartment of the mitochondrion. The mitochondrial matrix contains a concentrated mixture of special enzymes that catalyze oxidation reactions, as well as the mitochondrial genome and the proteins needed to express mitochondrial genes. |
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| membrane enclosed organelle, about the size of a bacterium, that carries out ozidative phosphorylation and produces most of the ATP in eucaryotic cells |
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| conversion of nitrogen from the atmosphere into nitrogen-containing organic molecules by soil bacteria and cyanobacteria |
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| Oxidative Phosphorylation |
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| Process in bacteria and mitochondria in which ATP formation is driven by the transfer of electrons from food molecules to molecular oxygen. Involves the intermediate generation of a pH gradient across a membrane and chemiosmotic coupling. |
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| The process by which plants and some bacteria use the energy of sunlight to drive the synthesis of organic molecules from carbon dioxide and water. |
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| Large multiprotein complex containing chlorophyll that captures light energy |
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| small, lipid-soluble, mobile electron carrier molecule found in the respiratory and photosynthetic electron transport chain. |
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| In photosynthetic membranes, a protein complex that contains a specialized pair of chlorophyll molecules that performs photochemical reactions to convert the energy of photons into high energy electrons for transport down the photosynthetic electron transport chain |
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| Pair of molecules in which one acts as an electron donor and one as an electron acceptor in an oxidation reduction reaction; for example, NADH(donor) and NAD+(acceptor) |
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| A measure of the tendency of a given redox pair to donate electrons. |
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| A reaction in which electrons are transferred from one chemical species to another. An oxidation reduction reaction. |
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| The large interior space of a chloroplast, containing enzymes that incorporate CO2 into sugars in the carbon-fixation stage of photosynthesis |
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| Protein that makes up the coat of one type of transport vesicle. This protein coated vesicle buds from the golgi apparatus on the outward secretory pathway and bud from the pasma membrane on the inward endocytic pathway. |
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| Small membrane-enclosed organelle with a cage of proteins on its cytosolic surface. It is formed by the pinching off of a protein-coated region of membrane. |
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| Contents of the main compartment of the cytoplasm, excluding membrane-enclosed organelles. |
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| Uptake of material into a cell by an invagination of the plasma membrane and its internalizaton in a membrane-bounded vesicle. |
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| Labyrinthian membrane-enclosed compartment in the cytoplasm of eucaryotic cells, where lipids and secreted and membrane-bound proteins are made. |
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| Membrane-enclosed compartment of a eucaryotic cell through which endocytosed material passes on its way to lysosomes. |
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| Process by which most molecules are secreted from a eucaryotic cell. These molecules are packaged in membrane-enclosed vesicles that fuse with the plasma membrane, releasing their contents to the outside. |
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| Membrane-enclosed organelle in eucaryotic cells where the proteins and lipids made in the endoplasmic reticulum are modified and sorted for transport to other sites. |
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| Intracellular membrane-enclosed organelle containing digestive enzymes, typically those most active at the acid pH found in these organelles. |
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| Membrane-enclosed organelle |
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| Any organelle in the eucaryotic cell that is surrounded by a lipid bilayer membrane, for example, the endoplasmic reticulum, golgi apparatus, and lysosome. |
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| Double membrane surrounding the nucleus. Consists of outer and inner membranes perforated by nuclear pores. |
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| Channel through the nuclear envelope that allows selected large molecules to move between the nucleus and the cytoplasm. |
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| Small membrane-enclosed organelle that uses molecular oxygen to oxidize organic molecules. Contains some enzymes that produce hydrogen peroxide and others that degrade it. |
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| A cell such as a macrophage or neutrophil that is specialized to take up particles and microorganisms by phagocytosis. |
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| The process by which particulate material is engulfed by a cell. |
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| Type of Endocytosis in which soluble materials are taken up from the environment and incorporated into vesicles for digestion. |
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| A family of small GTP-binding proteins present on the surgacesof transport vesicles and organelles that serve as molecular markers identifying each membrane type. Rab proteins help to ensure that transport vesicles fuse only with the correct membrane. |
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| Receptor-mediated endocytosis |
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Definition
| Mechanism of selective uptake of material by animal cells in which a macromolecule binds to a receptor in the plasma membrane and enters the cell in a clathrin coated vesicle. |
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| Rough Endoplasmic Reticulum |
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| region of the endoplasmic reticulum associated with ribosomes and involved in the synthesis of secreted and membrane-bound proteins. |
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| Production and release of a substance from a cell |
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| Membrane-enclosed organelle in which molecules destined for secretion are stored prior to relase. Sometimes called a secretory granule because darkly staining contents make the organelle visible as a small solid object. |
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| Amino acid sequence that directs a protein to a specific location in the cell, such as the nucleus or the mitochondria. |
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| One of a family of membrane proteins responsible for the selective fusion of vesicles with a target membrane inside the cell. |
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| Membrane vesicles that carry proteins from one intracellular compartment to another, for example from the ER to the Golgi apparatus. |
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| Unfolded Protein Response |
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| Cellular response triggered by the accumulation of misfolded proteins in the endoplasmic reticulum and more of the molecular machinery needed to restore proper protein folding and processing. |
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| Transport of material between organelles in the eucaryotic cell via membrane-enclosed vesicles. |
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