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77 Cards in this Set
- Front
- Back
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Endoplasmic reticulum (ER)
Rough |
An extensive membranous network in eukaryotic cells, continuous with the outer nuclear membrane and composed of ribosome-studded regions
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Endoplasmic Reticulum (ER)
Smooth |
An extensive membranous network in eukaryotic cells, continuous with the outer nuclear membrance and ribosome-free regions
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Centrosome
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Material present in the cytoplasm of all eukaryotic cells, important during cell division; the microtubule-organizing center
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Peroxisome
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A microbody containing enzymes that transfer hydrogen from various substrates to oxygen, producing and then degrading hydrogen peroxide
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Microvillus (microvilli)
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One of many fine, fingerlike projections of the epithelial cells in the lumen of the small intestine that increase its surface area
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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 and transport functions
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Microfilaments
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A solid rod of actin protein in the cytoplasm of almost all eukaryotic cells, making up part of the cytoskeleton and acting alone or with myosin to cause cell contraction
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Intermediate Filament
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A component of the cytoskeleton that includes all filaments intermediate in size between microtubules and microfilaments
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Microtubule
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A hollow rod of tubulin protein in the cytoplasm of all eukaryotic cells and in cilia, flagella, and the cytoskeleton
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Lysosome
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A membrane-enclosed bag of hydrolytic enzymes found in the cytoplasm of eukaryotic cells
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Mitochondrion
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An organelle in eukaryotic cells that serves as the site of cellular respiration
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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
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Ribosome
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A cell organelle constructed in the nucleolus and functioning as the site of protein synthesis in the cytoplasm; consists of rRNA and protein molecules, which make up two subunits
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Nucleus
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1) An atom's central core, containing protons and neutrons.
2) The chromosome-containing organelle of a eukaryotic cell. 3) A cluster of neurons |
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Chromatin
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The complex of DNA and proteins that makes up a eukaryotic chromosome. When the cell is not dividing, chromatin exists as a mass of very long, thin fibers that are not visible with a light microscope.
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Nucleolus
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A specialized structure in the nucleus, formed from various chromosomes and active in the synthesis of ribosomes
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Nuclear Envelope
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The membrane in eukaryotes that encloses the nucleus, separating it from the cytoplasm
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Central Vacuole
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A membranous sac in a mature plant cell with diverse roles in reproduction, growth development
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Tonoplast
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A membrane that encloses the central vacuole in a plant cell, separating the cytosol- from the cell sap
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Chloroplast
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An organeele found only in plants and photosynthetic protists that absorbs sunlight and uses it to drive the synthesis of organic compounds fromcarbon dioxide and water
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Plasmodesmata
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An open channel in the cell wall of plants through which strands of cytosol connect from adjacent cells
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Cell Wall
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A protective layer external to the plasma membrane in plant cells, bacteria, fungi, and some protists. In plant cells, the wall is formed of cellulose fibers embedded in a polysaccharide-protein matrix, The primary cell wall is thin and flexible, whereas the secondary cell wall is stronger and more rigid and is the primary constituent of wood.
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Peroxisome
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A microbody containing enzymes that transfer hydrogen fromvarious substrates to oxygen, producing and then degrading hydrogen peroxide
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Chromatin
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The complex of DNA and proteiins that nmakes up a eukaryotic chromosome. When the cell is not dividing, chromatin exists as a mass of very long, thin fibers that are not visible with a light microscope
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Nuclear Lamina
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A netlike array of protein filaments that maintains the shape of the nucleus
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Nucleolus
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A specialized structure in the nucleus, formed from various chromosomes and active in the synthesis of ribosomes
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Phagocytosis
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A type of endocytosis involving large, particulate substances
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light microscope
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the first microscopes used by Renaissance scientists, use light and lenses to magnify the image of the specimen; light is refracted to magnify the image
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resolving power
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a measure of the clarity of the image; the minimum distance two points can be separated and still be distinguished as two separate points
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electron microscope
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a form of microscopy in which a beam of electrons are passed through the specimen
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transmission electron microscope (TEM)
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used predominantly to study the internal ultrastructure of cells; focus a beam of electrons, using electromagnets, through a small portion of the specimen
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scanning electron microscope (SEM)
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useful for detailed study of the surface of the specimen; great depth of field results in an image that appears three-dimensional
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cell fractionation
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to take cells apart, separating the major organelles so that their functions can be studied
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ultracentrifuges
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powerful centrifuges that can spin the solution at speeds of up to 80,000 revolutions per minute
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endomembrane
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a system made up of many different membranes that are related either through direct physical continuity or as the transfer of membrane segments as tiny vesicles; includes the nuclear envelope, endoplasmic reticulum, Gogli apparatus, lysosomes, various kinds of vacuoles, and the plasma membrane; thickness, molecular composition, and metabolic behavior of a membrane can change over time
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Glycoproteins
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proteins that are covalently bonded to carbohydrates
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Transport vesicles
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vesicles that are in transit from one part of the cell to another that transport cellular products
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Food vacuoles
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large, membrane bound sacs formed by phagocytosis
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Contractile vacuoles
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used by many protests, etc. to pump excess water from the cell
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Cristae
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convoluted infoldings of the inner membrane in a mitochondrion; encloses the mitochondrial matrix; gives the inner membrane a large surface area that enhances productivity of cellular respiration
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Centrioles
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centrioles are composed of nine sets of triplet molecules; a pair of centrioles is located within the centrosome of an animal cell
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Flagella
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locomotive appendages that protrude from some cells; usually limited to one or a few per cell
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Cilia
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locomotive appendages that protrude from some cells; usually occur in large numbers across the cell surface
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Basal body
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structure that anchors the microtubule assembly within a flagella or cilia in the cell; structurally identical to a centriole
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Dynein
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a motor molecule (protein) that connects microtubule doublets together in a cilia or flagella; responsible for the beating motion of the cellular extension; undergoes a series of movements caused by changes in the conformation of the protein powered by ATP
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Actin
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a globular protein which composes microfilaments in the cytoskeleton
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Myosin
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a protein that is prevalent in muscle cells, functions as a motor molecule, it is found in an alternating pattern with actin; allows the muscle cells to shorten
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Pseudopodia
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an ameboid cell crawls along a surface by extending and flowing into this cellular extension; composed of actin-myosin fibers; white blood cells in humans move by crawling
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Selective permeability
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a key feature of plasma membranes;
allows some substances to cross a membrane more easily than others |
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Amphipathic
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contains both water-loving and water-fearing components
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Fluid mosaic model
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the current model used to describe the structure of membranes;
according to this model, the membrane is a mosaic of protein molecules bobbing in a fluid bilayer of phospholipids |
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Integral proteins
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generally transmembrane proteins, with hydrophobic regions (stretches of nonpolar amino acids) that completely span the hydrophobic interior of the membrane
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Peripheral proteins
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proteins that are not embedded in the lipid bilayer at all;
loosely bound to the surface of the membrane, often to the exposed parts of integral proteins |
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Transport proteins
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integral proteins that selectively transport molecules across the membrane
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Diffusion
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the tendency for molecules of any substance to spread out into the available space;
a spontaneous process that decreases free energy |
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Concentration gradient
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in the absence of other forces, a substance will diffus efrom where it is more concentrated to where it is less concentrated (down its conc. gradient)
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Passive transport
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the diffusion of a substance across a biological membrane;
the cell does not have to expend energy to make this happen |
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Hypertonic
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when comparing two solutions of unequal solute concentration, refers to the solution with a higher conc. of solute
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Hypotonic
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when comparing two solutions of unequal solute concentration, refers to the solution with a lower conc. of solute
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Isotonic
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describes two solutions that are equal in solute conc.
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Osmosis
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a spcial case of active transport;
diffusion of water across a selectively permeable membrane |
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Osmoregulation
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the control of water balance
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Facilitated diffusion
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the spontaneous passage of molecules and ions, bound to specific carrier proteins, across a biological membrane down their conc. gradients
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Gated channels
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proteins that respond to a stimulus by opening or closing;
stimulus may be electrical or chemical |
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Active tranpsor
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a process by which a cell moves a solute against its conc. gradient by expending its own energy
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Sodium-potassium pump
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a transport protein which exchanges sodium for potassium across the membrane of animal cells in order to maintain specific conc. of each within the cell;
the main electrogenic pump of animal cells |
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Membrane potential
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the voltage across a membrane;
reflects the separation of charges across a membrane |
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Electrochemical gradient
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the combination of the electrical gradient and the chemical gradient that drive the movement of ions across membranes
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Electrogenic pump
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a transport protein that generates voltage across a membrane, storing energy in the form of voltage
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Proton pump
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the main electrogenic pump plant, fungi, and bacteria cells;
actively transports hydrogen ions out of the cell |
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Cotransport
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a mechanism by which a single ATP-powered pump that transports a specific solute can indirectly drive the active transport of several other solutes
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Exocytosis
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a process by which cells secrete macromolecules by the fusion of vesicles with the plasma membrane
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Endocytosis
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a process by which cells take in macromolecules and particular matter by forming new vesicles from the plasma membrane
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Phagocytosis
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a process by which a cell engulfs a particle by wrapping pseudopodia around it and packaging it within a membrane enclosed sac; the sac then combines with a lysosome and the particle is digested
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Pinocytosis
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a process by which the cell "gulps" droplets of extracellular fluid in tiny vesicles
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Receptor-mediated endocytosis
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endocytosis that occurs when a specific molecule comes into to contact with specific membrane proteins
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Ligands
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a general term for any molecule that binds specifically to a receptor site of another molecule;
from the Latin "ligare" which means "to bind" |
