Chapter 4 Vocab

Question 1

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

Answer 1

light microscope (LM)

Question 2

any of several membrane-enclosed structures with specialized functions, suspended in the cytosol of eukaryotic cells

Answer 2

organelle

Question 3

a microscope that uses magnets to focus an electron beam on or through a spectrum, resulting in a practical resolution of a hundredfold greater than that of a light microscope using standard techniques. A transmission electron microscope (TEM) is used to study the internal structure of thin sections of cells. A scanning electron microscope (SEM) is used to study the fine details of the cell surface.

Answer 3

electron microscope (EM)

Question 4

a microscope that uses an electron beam to scan the surface of the sample, coated with metal atoms, to study details of its topography

Answer 4

scanning electron microscope (SEM)

Question 5

a microscope that passes electron beam through very thin sections stained with metal atoms and is primarily used to study the internal ultrastructure of cells

Answer 5

transmission electron microscope (TEM)

Question 6

the disruption of a cell and separation of its parts by centrifugation at successively higher speeds

Answer 6

cell fractionation

Question 7

the contents of the cell bounded by the plasma membrane; in eukaryotes, the portion exclusive of the nucleus

Answer 7

cytosol

Question 8

a type of cell with membrane-enclosed nucleus and membrane-enclosed organelles. Organisms with eukaryotic cells (protists, fungi, and animals) are called eukaryotes

Answer 8

eukaryotic cell

Question 9

No nucleus

Answer 9

prokaryotic cell

Question 10

a non-membrane-bounded region in a prokaryotic cell where the DNA is concentrated

Answer 10

nucleoid

Question 11

the contents of the cell bounded by the plasma membrane; in eukaryotes, the portion exclusive of the nucleus

Answer 11

cytoplasm

Question 12

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

Answer 12

plasma membrane

Question 13

an atom’s central core, containing protons and neutrons; the organelle of a eukaryotic cell that contains the genetic material in the form of chromosomes, made up of chromatin; a cluster of neutrons

Answer 13

nucleus

Question 14

in a eukaryotic cell, the double membrane that surrounds the nucleus, perforated with pores that regulate traffic with the cytoplasm. The outer membrane is continuous with the endoplasmic reticulum

Answer 14

nuclear envelope

Question 15

a netlike array of protein filaments that lines the inner surface of the nuclear envelope and helps maintain the shape of the nucleus

Answer 15

nuclear lamina

Question 16

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

Answer 16

chromosome

Question 17

the complex of DNA and proteins that makes up eukaryotic chromosomes. When the cell is not dividing, chromatin exists in its dispersed form, as a mass of very long, thin fibers that are not visible with a light microscope

Answer 17

chromatin

Question 18

a specialized structure in the nucleus, consisting of chromosomal regions containing ribosomal RNA (rRNA) genes along with ribosomal proteins imported from the cytoplasm; site of rRNA synthesis and ribosomal subunit assembly

Answer 18

nucleolus

Question 19

a complex of rRNA and protein molecules that function as a site of protein synthesis in the cytoplasm; consists of a large and small subunit. In eukaryotic cells, each subunit is assembled in the nucleolus

Answer 19

ribosome

Question 20

the collection of membranes inside and surrounding a eukaryotic cell, related either through direct physical contact or by the transfer of membranous vesicles; includes the plasma membrane, the nuclear envelope, the smooth and rough endoplasmic reticulum, the Golgi apparatus, lysosomes, vesicles, and vacuoles

Answer 20

endomembrane system

Question 21

a membranous sac in the cytoplasm of a eukaryotic cell

Answer 21

vesicle

Question 22

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

Answer 22

endoplasmic reticulum (ER)

Question 23

the portion of the ER that is free of ribosomes

Answer 23

smooth ER

Question 24

the portion of the ER with ribosomes attached

Answer 24

rough ER

Question 25

a protein with one or more covalently attached carbohydrates

Answer 25

glycoprotein

Question 26

a small membranous sac in a eukaryotic cell's cytoplasm carrying molecules produced by the cell

Answer 26

transport vesicle

Question 27

an organelle in eukaryotic cells consisting of stacks of flat membranous sacs that modify, store, and route products of the ER and synthesize some products, notably noncellular carbohydrates

Answer 27

Golgi apparatus

Question 28

a membrane-enclosed sac of hydrolytic enzymes found in the cytoplasm of animal cells and some protists. Contains a stockpile of digestive enzymes, important in breaking down nutrients, destroying bacteria, recycling, and development

Answer 28

lysosome

Question 29

a type of endocytosis in which large particulate substances or small organisms are taken up by a cell. It's carried out by some protists and by certain immune cells of animals (in mammals, mainly macrophages, neutrophilis, and dendritic cells)

Answer 29

phagocytosis

Question 30

a membrane-bounded vesicle whose specialized function varies in different kinds of cells

Answer 30

vacuole

Question 31

a membranous sac fromed by phagocytosis of microorganisms or particles to be used as food by the cell

Answer 31

food vacuole

Question 32

a membranous sac formed that helps moves excess water out of certain freshwater protists

Answer 32

contractile vacuole

Question 33

in a mature plant cell, a large membranous sac with diverse roles in growth, storage, and sequestration of toxic substances

Answer 33

central vacuole

Question 34

an organelle in eukaryotic cells that serves as the site of cellular respiration; uses oxygen to break down organic molecules and synthesize ATP

Answer 34

mitochondria

Question 35

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

Answer 35

chloroplast

Question 36

the theory that mitochondria and plastids, including chloroplasts, originated as prokaryotic cells engulfed by an ancestral eukaryotic cell. The engulfed cell and its host cell then evolved into a single organism

Answer 36

endosymbiont theory

Question 37

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

Answer 37

cristae

Question 38

the compartment of the mitochondrion enclosed by the inner membrane and containing enzymes and substrates for the citric acid cycle, as well as ribosomes and DNA

Answer 38

mitochondrial matrix

Question 39

a flattened, membranous sac inside a chloroplast. Often exist in stacks called grana that are interconnected; their membranes contain molecular "machinery" used to convert light energy to chemical energy

Answer 39

thylakoid

Question 40

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

Answer 40

granum

Question 41

the dense fluid within the chloroplast surrounding the thylakoid membrane and containing ribosomes and DNA; involved in the synthesis of organic molecules from carbon dioxide and water

Answer 41

stroma

Question 42

one of a family of closely related organelles that includes chloroplasts, chromoplasts, and amlyoplasts. Found in cells of photosynthetic eukaryotes

Answer 42

plastid

Question 43

an organelle containing enzymes that transfer hydrogen atoms from various substrates to oxygen (O2), producing and then degrading hydrogen peroxide (H2O2)

Answer 43

peroxisome

Question 44

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

Answer 44

cytoskeleton

Question 45

a protein that interacts with cytoskeletal elements and other cell components, producing movement of the whole cell or parts of the cell

Answer 45

motor protein

Question 46

a hollow rod composed of tubulin proteins that makes up part of the cytoskeleton in all eukaryotic cells and is found in cilia and flagella

Answer 46

microtubules

Question 47

a structure present in the cytoplasm of animal cells that functions as a microtubule-organizing center and is important during cell division; has 2 centrioles

Answer 47

centrosome

Question 48

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

Answer 48

centriole

Question 49

a long cellular appendage apecialized for locomotion. Like motile cilia, eukaryotic flagella have a core with 9 outer doublet microtubules and 2 inner single mictrotubules (the "9+2" arrangement) ensheathed in an extension of the plasma membrane.

Answer 49

flagella

Question 50

a short appendage containing microtubules in eukaryotic cells. A motile cillium is specialized for locomotion or moving fluid past the cell; formed from a core of 9 outer doublet microtubules and 2 inner single microtubules (the "9+2" arrangement) ensheathed in an ectension of the plasma membrane. Primary cillium usually nonmotile and plays sensory and signaling role; lack 2 inner microtubules (the "9+0" structure)

Answer 50

cilia

Question 51

a eukaryotic cell structure consisting of a "9+0" arrangement of microtubule triplets. The basal body may organize the microtubule assembly of a cilium or flagellum and is structurally very similar to a centriole

Answer 51

basal body

Question 52

in cilia and flagella, a large motor protein extending from 1 microtubule doublet to the adjacent doublet. ATP hydrolysis drives changes in its shape that lead to bending of cilia and flagella

Answer 52

dynein

Question 53

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

Answer 53

microfilament

Question 54

a globular protein that links into chains, 2 of which twist helically about each other, forming microfilaments (actin filaments) in muscle and other kinds of cells

Answer 54

actin

Question 55

a type of motor protein that associates into filaments that interact with actin filaments to cause cell contraction

Answer 55

myosin

Question 56

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

Answer 56

intermediate filament

Question 57

a protective layer external to the plasma membrane in the cells of plants, prokaryotes, fungi and some protists. Polysaccharides such as cellulose (in plants and some protists), chitin (in fungi), and peptidoglycan (in bacteria) are important structural components of them

Answer 57

cell wall

Question 58

the level of protein structure referring to the specific linear sequence of amino acids

Answer 58

primary cell wall

Question 59

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

Answer 59

middle lamella

Question 60

regions of repetitive coiling of folding of the polypeptide backbone of a protein due to hydrogen bonding between constituents of the backbone (not the side chains)

Answer 60

secondary cell wall

Question 61

the meshwork surrounding animal cells, consisting of glycoproteins, polysaccharides and proteoglycans synthesized and secreted by the cells

Answer 61

extracellular matrix (ECM)

Question 62

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

Answer 62

collagen

Question 63

a large molecule consisting of a small core protein with many carbohydrate chains attached, found in the extracellular matrix of animal cells' may consist of up to 95% carbohydrate

Answer 63

proteoglycan

Question 64

n an angiosperm, the stalk portion of the stamen, the pollen-producing reproductive organ of a flower

Answer 64

fibronectin

Question 65

in animal cells, a transmembrane receptor protein with 2 subunits that interconnects the extracellular matrix and the cytoskelteton

Answer 65

integrin

Question 66

an open channel through the cell wall that connects the cytoplasm of adjacent plant cells, allowing water, small solutes, and some larger molecules to pass between the cells

Answer 66

plasmodesmata