Chapter 7 Biology Key Words

Front 1

resolving power

Back 1

measure of clarity of image

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light microscope

Back 2

optical instrument with lenses that refract visible light to magnify images

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electron microscope

Back 3

focuses beam of electrons through speciman or surface of speciman

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TEM vs. SEM

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TEM: internal ultrastucture of cells
SEM: detailed study of surface of speciman

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cell frationation

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taking cells apart, separating major organelles so functions can be studied

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ultracentrifuge

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most powerful machine for spinning test tubes

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eukaryotic cell

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cell with membrane-enclosed nucleus and membrane-enclosed organelles

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prokaryotic cell

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cell lacking membrane-enclosed nucleus and membrane-enclosed organelles

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nucleoid

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dense region of DNA in a prokaryotic cell

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cytoplasm

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interior of prokaryotic cell

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plasma membrane

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at boundary of every cell; selective barrier allowing sufficient passage of oxygen, nutrients, and wastes to service cell

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nucleus

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contains most of genes in eukaryotic cell

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nuclear lamina

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lining nuclear envelope; netlike array of protein filaments that maintain shape of nucleus

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chromatin

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in nucleus; fibrous material that DNA and proteins are organized into

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chromosomes

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threadlike, gene-carrying structure in nucleus; each consists of 1 very long DNA molecule and associated proteins

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nucleolus

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specialized structure in nucleus; formed from various chromosomes and active in synthesis of ribosomes

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ribosomes

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particles made of ribosomal RNA and protein; are organelles that carry out protein synthesis

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free ribosomes vs. bound ribosomes

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free: suspended in cytosol
bound: attached to outside of endoplasmic reticulum, or nuclear envelope

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endomembrane system

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collection of membranes inside and around a eukaryotic cell; related through direct physical contact or by transfer of membranous vesicles

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endoplasmic reticulum

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membranous labyrinth; consists of network of membranous tubules and sacs called cisternae

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transport vesicles

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tiny membranous sac in cell's cytoplasm carrying molecules produced by cell

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smooth vs. rough ER

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smooth: portion of ER free of ribosomes
rough: portion of ER studded with ribosomes

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Golgi apparatus

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center of manufacturing, warehousing, sorting, and shipping; products of ER are modified and stored and then sent out

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lysosomes

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membrane-bounded sac of hydrolytic enzymes that cells use to digest macromolecules; also hydrolyze proteins, polysaccharides, fats, and nucleic acids

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phagocytosis

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type of endocytosis involving large, particulate substances; amoebas and other protists eat by engulfing smaller organisms or other food particles

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vacuole

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membrane-enclosed sac taking up most of interior of mature plant cell and containg a variety of subtances important in plant reproduction, growth and development

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mitochondria

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sites of cellular respiration, catabolic process that generates ATP by extracting evergy from sugars, fats, and other fuels with help of oxygen

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plastids

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one of a family of closely related plant organelles; ex.: chloroplasts, chromoplasts, and leucoplasts

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cristae

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infoldings of inner membrane of mitochondria

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mitochondrial matrix

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2nd compartment of mitochondrion; enclosed by inner membrane; contains many different enzymes, mitochondrial DNA and ribosomes

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thylakoids

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flattened membrane sac inside chloroplast, used to convert light energy to chemical energy

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granum

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stacked portion of thylakoid membrane in chloroplast; funtion in light reactions of photosynthesis

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stroma

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fluid of chloroplast surrouding the thylakoid membrane; involved in synthesis of organic molecules from carbon dioxide and water

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peroxisome

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specialized metabolic compartment bounded by a single membrane; contain enzymes that transfer hydrogen from various substrates to oxygen, producing hydrogen peroxide as by-product, organelle name

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cytoskeleton

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network of fibers extending throughout cytoplasm; organizing structures and activites of cell

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microtubule

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thickest of 3 types of fibers making up cytoskeleton

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microfilaments

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thinnest of 3 types of fibers making up cytoskeleton

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intermediate filaments

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fibers with diameters in middle range of 3 types of fibers making up cytoskeleton