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61 Cards in this Set
- Front
- Back
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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Organelles
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subcellular structures
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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
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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
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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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Prokaryotic cell
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cells that lack a defined nucleus and many important internal cellular structures
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Nucleoid
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a region inside prokaryotic cells where the genetic material is concentrated, not bound by a membrane
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Cytoplasm
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the entire region from the nuclear membrane (in eukaryotic cells) to the cellular membrane; internal body of the cell
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Cytosol
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semi-fluid medium that composes the cytoplasm
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Plasma membrane
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the outer boundary of a cell; functions as a selective barrier that allows sufficient passage of oxygen, nutrients, and wasters to service the entire volume of the cell
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Nucleus
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contains most of the genes that control the eukaryotic cell; generally the most conspicuous organelle inside a eukaryotic cell
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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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Chromatin
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material inside the nucleus which is composed of the genetic material, DNA, etc; appears through a light microscope as a diffuse mass
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Chromosomes
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when cell prepares to divide, chromatin condenses enough to be discerned as separate structures called chromosomes; each species has a characteristic number of chromosomes (humans have 46)
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Nucleolus
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a prominent structure within the nondividing nucleus where components of ribosomes are synthesized and assembled
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Ribosomes
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the sight where cells make proteins; cells with high rates of protein synthesis have a large number of ribosomes; free ribosomes are suspended in the cytosol; bound ribosomes are attached to the outside of the endoplasmic reticulum
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Endomembrane system
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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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Endoplasmic reticulum
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an extensive labyrinth of membranes consisting of a network of membranous tubule and sacs called cisternae
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Smooth ER
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portion of the ER that lacks ribosomes on its cytoplasmic surface; functions in diverse metabolic processes such as production of lipids & steroids, metabolism of carbohydrates, and detoxification of drugs and poisons
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Rough ER
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portion of the ER that is studded with ribosomes on its cytoplasmic surface; confluent with the nuclear membrane which is also studded with ribosomes; involved mainly with the composition of secretory proteins and membranes
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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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Golgi apparatus
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the cellular center of manufacturing warehousing, sorting, and shipping; extensive in cells that specialize in secretion; consists of flattened membranous sacs – or cisternae; vesicles transfer materials from the Golgi to other structures
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Lysosome
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a membrane-bounded sac of hydrolytic enzymes that the cell uses to digest macromolecules; maintains an acidic pH by pumping H+ ions in from the cytosol so that the enzymes can work most efficiently
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Phagocytosis
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enzymatic hydrolysis occurs in many cases, one is when one cell engulfs another smaller organism or food particle and digests it
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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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Central vacuole
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mature plant cells generally contain this large central vacuole used to store excess organic and inorganic molecules
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Tonoplast
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membrane that surrounds the central vacuole in plant cells
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Mitochondria
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the sites of cellular respiration in eukaryotic cells
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Chloroplasts
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the sites of photosynthesis in plant cells and among some single celled algae
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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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Mitochondrial matrix
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enclosed by the mitochondrial matrix; some steps of cellular respiration occur here; concentrated with many enzymes
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Peroxisome
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a specialized metabolic compartment bounded by a single membrane; contain enzymes that transfer hydrogen from various substrates to oxygen, producing H2O2(toxic) but also contains enzymes to convert hydrogen peroxide into water; serve diverse functions
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Cytoskeleton
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a network of fibers extending throughout the cytoplasm; plays a major role in organizing the structure and activities of the cell; give mechanical support to the cell and maintain its shape
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Microtubules
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thickest of the fibers that make up the cytoskeleton; found in the cytoplasm of all eukaryotic cells; composed of tubulin; involved in the movement of chromosomes during cell division
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Microfilaments
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also called actin filaments; the thinnest filaments that make up the cytoskeleton
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Intermediate filaments
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fibers in the cytoskeleton that lie between microtubules and microfilaments in size
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Centrosome
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a region near the nucleus from which microtubules grow out
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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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Cytoplasmic streaming
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a circular flow of cytoplasm within plant cells; speeds the distribution of materials within cells
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Cell wall
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a distinguishing feature of plant cells; protects the plant cell, maintains its shape, and prevents excessive uptake of water
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Extracellular matrix
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composed predominantly of glycoproteins that are secreted by the cells
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Collagen
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the most abundant glycoprotein found in the ECM; forms strong fibers outside cells
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Proteoglycans
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glycoproteins composed primarily of carbohydrates and can be found in large complexes
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Fibronectins
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bind to the receptor proteins called integrins
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Integrins
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receptor proteins that are built into the plasma membrane; located expansively across the membrane and bind to the cytoskeleton on the interior of the cell; help to integrate changes that occur inside and outside the cell
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Plasmodesmata
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channels located through and between the cell walls of plants that allow communication and transport directly between cells
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Tight junctions
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intercellular junctions that form continuous belts around the cell; fuses cells together, often to prevent fluid leakage across a layer of epithelial cells; i.e. found between intestinal epithelial cells
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Desmosomes
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form anchoring “rivets” between cells, resulting in strong epithelial sheets; reinforced by intermediate filaments made of the sturdy protein keratin
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Gap junctions
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gaps that provide cytoplasmic channels between adjacent cells; large of enough for small molecules to pass through; especially important in animal embryos
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