Biology Chapter 7

Front 1

light microscpe (LM)

Back 1

an optical instrument with lenses that refract (bend) visible light to magnify images of specimens

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resolving power

Back 2

a measure of the clarity of the image

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organelle

Back 3

one of several formed bodies with a specialized function, suspended in the cytoplasm and found in eukaryotic cells

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electron microscopes (EM)

Back 4

A microscope that focuses an electron beam through a specimen, resulting in resolving power a thousandfold greater than that of a light microscope.

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transmission electron microscope (TEM)

Back 5

used to study the internal structure of thin sections of cells

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scanning electron microscope (SEM)

Back 6

used to study the fine details of cell surfaces

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cell fractionation

Back 7

the disruption of a cell and separation of its organelles by centrifugation

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ultracentrifuges

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instruments used to fractionate cell, a merry-go-round for test tubes capable of spinning at various speeds

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prokaryotic cell

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a type of cell lacking a membrane-enclosed nucleus and membrane-enclosed organelles; found only in the domains Bacteria and Archaea

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nucleoid

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a dense rigion of DNA in a prokaryotic cell

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cytoplasm

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the entire contents of the cell, exclusive of the nucleus, and bounded by the plasma membrane

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cytosol

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the semifluid portion of the cytoplasm

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plasma membrane

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the membrane at the boundry of every cell that acts as a selective barrier, thereby regulation the cell's chemical composition

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nucleus

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The chromosome-containing organelle of 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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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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chromosomes

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A threadlike, gene-carrying structure found in the nucleus. Each chromosome consists of one very long DNA molecule and associated proteins. See chromatin.

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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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ribosomes

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A cell organelle constructed in the nucleolus, functioning as the site of protein synthesis in the cytoplasm.

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endomembrane system

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The collection of membranes inside and around a eukaryotic cell, related either through direct physical contact or by the transfer of membranous vesicles.

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endoplasmic reticulum (ER)

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

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smooth ER

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

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rough ER

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That portion of the endoplasmic reticulum studded with ribosomes.

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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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Vessels in transit from one part of the cell to another

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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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lysosome

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A membrane-enclosed bag of hydrolytic enzymes found in the cytoplasm of eukaryotic cells.

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food vacuoles

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Vacuoles formed by phagocytosis

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Contractile vacuoles

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Pumps excess water out of the cell

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vacuole

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A membrane-enclosed sac taking up most of the interior of a mature plant cell and containing a variety of substances important in plant reproduction, growth, and 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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mitochondrion

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An organelle in eukaryotic cells that serves as the site of cellular respiration.

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chloroplasts

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An organelle found only in plants and photosynthetic protists that absorbs sunlight and uses it to drive the synthesis of organic compounds from carbon dioxide and water.

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cristae

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An infolding of the inner membrane of a mitochondrion that houses the electron transport chain and the enzyme catalyzing the synthesis of ATP.

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mictochondrial matrix

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The compartment of the mitochondrion enclosed by the inner membrane and containing enzymes and substrates for the Krebs cycle.

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plastids

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One of a family of closely related plant organelles, including chloroplasts, chromoplasts, and amyloplasts (leucoplasts).

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thylakoids

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

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granum

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A stacked portion of the thylakoid membrane in the chloroplast. Grana function in the light reactions of photosynthesis.

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stroma

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

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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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cytoskeleton

Back 41

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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micortubule

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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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microfilament

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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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plastids

Back 44

One of a family of closely related plant organelles, including chloroplasts, chromoplasts, and amyloplasts (leucoplasts).

Front 45

thylakoids

Back 45

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

Front 46

granum

Back 46

A stacked portion of the thylakoid membrane in the chloroplast. Grana function in the light reactions of photosynthesis.

Front 47

stroma

Back 47

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

Front 48

peroxisome

Back 48

A microbody containing enzymes that transfer hydrogen from various substrates to oxygen, producing and then degrading hydrogen peroxide.

Front 49

cytoskeleton

Back 49

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

Front 50

micortubule

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A hollow rod of tubulin protein in the cytoplasm of all eukaryotic cells and in cilia, flagella, and the cytoskeleton.

Front 51

microfilament

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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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centrosome

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Material present in the cytoplasm of all eukaryotic cells and important during cell division; also called microtubule-organizing center.

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centriole

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A structure in an animal cell, composed of cylinders of microtubule triplets arranged in a 9 + 0 pattern. An animal cell usually has a pair of centrioles, which are involved in cell division.

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flagellum

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A long cellular appendage specialized for locomotion, formed from a core of nine outer doublet microtubules and two inner single microtubules, ensheathed in an extension of plasma membrane.

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cilium

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A short cellular appendage specialized for locomotion, formed from a core of nine outer doublet microtubules and two inner single microtubules ensheathed in an extension of plasma membrane.

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dynein

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A large contractile protein forming the sidearms of microtubule doublets in cilia and flagella.

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actin

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A globular protein that links into chains, two of which twist helically about each other, forming microfilaments in muscle and other contractile elements in cells.

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pseudopodium

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

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cytoplasmic streaming

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A circular flow of cytoplasm, involving myosin and actin filaments, that speeds the distribution of materials within cells.

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cell wall

Back 61

A protective layer external to the plasma membrane in plant cells, bacteria, fungi, and some protists. In the case of 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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primary cell wall

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Relatively thin and flexible wall

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middle lamella

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thin layer of adhesive extracellular material, primarily pectins, found between the primary walls of adjacent young plant cells.

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secondary cell wall

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Strong and more rigid wall, and is the primary constituent of wood

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extracellular matrix (ECM)

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The main ingredients of this are glycoproteins secreted by the cells.

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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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proteoglycans

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A glycoprotein in the extracellular matrix of animal cells, rich in carbohydrate.

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fibronectin

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These kind of glycoproteins bind to the receptor protein called integrins

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integrin

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A receptor protein that builts into the plasma membrane

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plasmodesma

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An open channel in the cell wall of plants through which strands of cytosol connect from adjacent cells.