Campbell Biology Ch 4-6

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flagellum

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Long cellular appendage specialized for locomotion

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G protein-coupled receptor

Back 2

single receptor protein in plasma membrane that responds to binding of a single molecule by activating a G protein. AKA G protein-linked receptor.

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cilium

Back 3

short cellular appendage containing microtubules.

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scaffolding protein

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a type of large relay protein which several other relay proteins are simultaneously attached, increasing the efficiency of signal transduction. (transduction - is the process by which DNA is transferred from one bacterium to another by a virus. It also refers to the process whereby foreign DNA is introduced into another cell via a viral vector.)

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noncompetitive inhibitor

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substance that reduces the activity of an enzyme by binding to a location remote from the active site, changing the enzyme's shape so that the active site no longer functions effectively.

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plasmodesmata

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holes, perforated channels in plant cell walls. an open channel in the cell wall of a plant through which strands of cytosol connect from an adjacent cell.

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feedback inhibition

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method of metabolic control in which the end product of a metabolic pathway acts as an inhibitor of an enzyme within that pathway.

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protein phosphatase

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enzyme that removes phosphate groups from proteins (dephosorylates), often functioning to reverse the effect of a protein kinase.

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glycoprotein

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a protein with one or more carbohydrates covalently attached to it.

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G protein

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a GTP-binding protein that relays signals from a plasma membrane signal receptor, known as a G protein-coupled receptor, to other signal transduction proteins inside the cell.

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diacylglycerol (DAG)

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a second messenger produced by the cleavage of certain kind of phospholipid in the plasma membrane.

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scanning electron microscope (SEM)

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a microscope that uses an electron beam to scan the surface of a sample to study details of its topography.

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pinocytosis

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type of endocytosis in which the cell ingests extracellular fluid and its dissolved solutes.

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active site

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the specific portion of an enzyme that binds the substrate by means of multiple weak interactions and that forms a pocket in which catalysis occurs.

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hypotonic

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when a solution surrounds a cell, will cause the solution to take up water.

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ligand

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a molecule that binds specifically to another molecule, usually a larger one.

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granum

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a stack of membrane-bounded thylakoids in the chloroplast. Grana function in the light reactions of photosynthesis.

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facilitated diffusion

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spontaneous passage of molecules or ions across a biological membrane with the assistance of specific transmembrane transport proteins.

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stroma

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within the chloroplast, the dense fluid of the chloroplast surround the thylakoid membrane; involved in the synthesis of organic molecules from carbon dioxide and water.

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crista (cristae - plural)

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an infolding of the inner membrane of mitochondrion that houses the electron transport chains and molecules of the enzyme catalyzing the synthesis of ATP (ATP synthase).

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vacuole

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a membrane-bound vesicle whose function varies in different kinds of cells.

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active transport

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movement of a substance across a cell membrane, with an expenditure of energy, against its concentration or electrochemical gradient; mediated by specific transport proteins.

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collagen

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a glycoprotein in the extracellular matrix of animal cells that forms strong fibers, found extensively in connective tissue and bone; the most abundant protein in the animal kingdom.

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osmoregulation

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regulation of solute concentrations and water balance by a cell or organism.

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phagocytosis

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type of endocytosis in which large particulate substances are taken up by a cell. It is carried out by some protists and by certain immune cells of animals.

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plasma membrane

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the membrane at the boundary of every cell that acts as a selective barrier, regulating the cell's chemical composition.

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microfilament

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a cable composed of actin proteins in the cytoplasm of almost every eukaryotic cell, making up part of the cytoskeleton and acting alone or with myosin to cause cell contraction; also known as actin filament.

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bioenergetics

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1) the overall flow and transformation of energy in an organism

2) the study of how energy flows through organisms

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allosteric regulation

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binding of regulatory molecule to a protein at one site that affects the function of the protein at a different site.

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catabolic pathway

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a metabolic pathway that releases energy by breaking down complex molecules to simpler compounds.

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anabolic pathway

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a metabolic pathway that consumes energy to synthesize a complex molecule from simpler compounds.

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transmission electron microscope (TEM)

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a microscope that passes an electron beam through very thin sections and is primarily used to study the internal ultrastructure of cells.

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endoplasmic reticulum (ER)

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an extensive membranous network in eukaryotic cells, continuous with the other nuclear membrane and composed of ribosome-studded (rough) and ribosome-free (smooth) regions.

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pseudopodium (pseudopodia, plural)

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a cellular extension of amoeboid cells used in moving and feeding.

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proton pump

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an active transport protein in a cell membrane that uses ATP to transport hydrogen ions out of a cell against their concentration gradient, generating a membrane potential in the process.

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thylakoid

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a flattened membranous sac inside the chloroplast. Thylakoids exist in an interconnected system in the chloroplast and contain the molecular "machinery" used to convert light energy to chemical energy.

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smooth ER

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the portion of the endoplasmic reticulum that is free of ribosomes.

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first law of thermodynamics

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the principal of conservation energy: Energy can be transferred and transformed, but it cannot be created or destroyed.

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induced fit

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induced by entry of the substrate, the change in shape of the active site of an enzyme so that it binds more snugly to the substrate.

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eukaryotic cell

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a type of cell with a membrane-enclosed nucleus and membrane-enclosed organelles. Organisms with eukaryotic cells are called eukaryotes. Protists, Plants, Fungi, Animals.

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peripheral protein

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a protein loosely bound to the surface of a membrane or to part of an integral protein and not embedded in the lipid bilayer.

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cytoskeleton

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a network of microtubules, microfilaments, and intermediate filaments that branch throughout the cytoplasm and serve a variety of mechanical, transport, and signaling functions.

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glycoprotein

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a protein with one or more carbohydrates covalently attached to it.

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potential energy

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the energy that matter possesses as a result of its location or spacial arrangement (structure).

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membrane potential

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difference in electrical charge (voltage) across a cell's plasma membrane due to the differential distribution of ions. Membrane potential affects the activity of excitable cells and the transmembrane movement of all charged substances.

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exocytosis

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cellular secretion of biological molecules by the fusion of vesicles containing them with the plasma membrane.

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hypertonic

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referring to a solution that, when surround a cell, will cause the cell to lose water.

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amphipathic

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having both a hydrophylic region and a hydrophobic region.

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passive transport

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the diffusion of a substance across a biological membrane with no expenditure of energy.

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second messenger

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a small, nonprotein, water-soluble molecule or ion, such as a calcium ion (Ca2+) or cyclic AMP, that relays a signal to a cell's interior in response to a signaling molecule bound by a signal receptor protein.

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phagocytosis

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a type of endocytosis in which large particulate substances are taken up by a cell. It is carried out by some protists and by certain immune cells of animals.

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thermodynamics

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the study of energy transformations that occur in a collection of matter.

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centrosome

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structure present in the cytoplasm of animal cells, important during cell division; functions as a microtubule-organizing center. Has two centrioles.

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exergonic reaction

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a spontaneous chemical reaction, in which there is a net release of free energy.

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receptor tyrosine kinase

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a receptor protein in the plasma membrane, the cytoplasmic (intracellular) part of which can catalyze the transfer of a phosphate group from ATP to a tyrosine on another protein.

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hormone

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in multicellular organisms, one of many types of secreted chemicals that are formed in specialized cells, travel in body fluids, and act on specific target cells in other parts of the body to change their functioning.

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intermediate filament

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a component of the cytoskeleton that includes filaments intermediate in size between microtubules and microfilaments.

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chromosome

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a cellular structure carrying genetic material, found in the nucleus of eykaryotic cells. Consists of very long DNA molecules and associated proteins. (a bacterial chromosome usually consists of a single circular DNA molecule and associated proteins. found in the nucleoid region, which is not membrane bounded).

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nuclear lamina

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a netlike array of protein filaments lining the inner surface of the nuclear envelope; it helps maintain the shape of the nuleus.

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middle lamella

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in plants, a thin layer of adhesive extracellular material, primarily pectins, found between the primary walls of adjaent young cells.

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endomembrane system

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collection of membranes inside and around a eukaryotic cell, related either through direct physical contact or by the transfer of membraneous vesicles, includes the smooth and rough endoplasmic reticulum, the Golgi apparatus, lysosomes, and vacuoles.

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integral protein

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typically a transmembrane protein with hydrophobic regions that extend into and often completely span the hydrophobic interior of the membrane and with hydrophilic regions in contact with the aqueous solution on ether side of the membrane (or lining the channel in the case of a channel protein).

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desmosome

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a type of intercellular junction in animal cells that functions as a rivet.

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electron microscope (EM)

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microscope uses magnets to focus an electron beam on or through a specimen. resolving power of a thousandfold greater than that of a light microscope.

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fibronectin

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a glycoprotein that helps animal cells attach to the extracellular matrix

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kinetic energy

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energy associated with the relative motion of objects. moving matter an perform work by imparting motion to other matter.

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plastid

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one of a family of closely related organelles that includes chloroplasts, chromoplasts, and amyloplasts (leucoplaslts). Plastids are found in cells of photosynthetic organisms

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centriole

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a structure in the centrosome of an animal cell composed of a cylinder of microtubule triplets arranged in a 9 + 0 pattern. a centrosome has a pair of centrioles.

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nucleus

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1) an atom's central core, containing protons and neutrons

2) chromosome-containing organelle of a eykaryotic cell

3) cluster of neurons

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gated channel

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a transmembrane protein channel that opens or closes in response to a particular stimulus.

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transport protein

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a transmembrane protein that helps a certain substance or class of closely related substances to cross the membrane.

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metabolism

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the totality of an organism's chemical reactions, consisting of catabolic and anabolic pathways, which manage the material and energy resources of the organism.

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protein kinase

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an enzyme that transfers phosphate groups from ATP to a protein, thus phosphorylating the protein.

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diffusion

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spontaneous movement of a substance down its concentration gradient, from a region where it is more concentrated to a region where it is less concentrated.

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Golgi apparatus

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an organelle in eukaryotic cells consisting of stacks of flat membranous sacs that modify, store, and route products of the endoplasmic reticulum and synthesize some products, notably noncellulose carbohydrates.

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energy coupling

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in cellular metabolism, the use of energy released from an exergonic reaction to drive an endergonic reaction.