Chapter 6

Question 1

cytosol

Answer 1

jellylike substance in which sub cellular components are suspended inside all cells

Question 2

eukaryotic cell

Answer 2

most DNA is in the nucleus bounded by a double membrane

Question 3

prokaryotic cell

Answer 3

DNA is concentrated in a region that is not membrane-enclosed called the nucleoid

Question 4

cytoplasm

Answer 4

the interior of all cells/the region between the nucleus and the plasma membrane

Question 5

plasma membrane

Answer 5

at the boundary of every cell, functions as a selective barrier that allows passage of enough oxygen, nutrients, and wastes to service the entire cell

Question 6

nucleus

Answer 6

contains most of the genes in a eukaryotic cell

Question 7

nuclear envelope

Answer 7

encloses the nucleus, separating its contents from the cytoplasm

Question 8

nuclear lamina

Answer 8

lines the nuclear side of the envelope, a netlike array of protein filaments that maintains the shape of the nucleus by mechanically supporting the nuclear envelope

Question 9

chromosomes

Answer 9

discrete units where DNA is organized

Question 10

chromatin

Answer 10

the complex of DNA and proteins making up chromosomes

Question 11

nucleolus

Answer 11

structure in the nucleus consisting of chromosomal regions containing rRNA genes and ribosomal proteins imported from the cytoplasm; site of rRNA synthesis and ribosomal subunit assembly

Question 12

ribosomes

Answer 12

made of ribosomal RNAs and proteins, carry out protein synthesis

Question 13

end-membrane system

Answer 13

includes the nuclear envelope, the ER, the Golgi apparatus, lysosomes, vesicles and vacuoles, and the plasma membrane

Question 14

vesicles

Answer 14

a membrane-bound sac in or outside a cell, helps transport

Question 15

endoplasmic reticulum (ER)

Answer 15

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

Question 16

smooth ER

Answer 16

outer surface lacks ribosomes, synthesizes lipids, metabolizes carbohydrates, detoxifies drugs and poisons, and stores calcium ions

Question 17

rough ER

Answer 17

studded with ribosomes on the outer surface, makes secretory proteins like glycoproteins (proteins with carbohydrates covalently bonded to them)

Question 18

transport vesicles

Answer 18

transports things from one part of the cell to another

Question 19

Golgi apparatus

Answer 19

consists of a group of associated, flattened, membranous sacs; a warehouse for receiving, sorting, shipping, and some manufacturing; cis face is the receiving side; trans face is the shipping side

Question 20

lysosomes

Answer 20

membranous sac of hydrolytic enzymes that many eukaryotic cells use to digest macromolecules

Question 21

phagocytosis

Answer 21

cell eating by engulfing smaller organisms or food particles

Question 22

vacuoles

Answer 22

large vesicles derived from the ER and Golgi apparatus

Question 23

food vacuoles

Answer 23

formed by phagocytosis of microorganisms or particles to be used as food by the cell

Question 24

contractile vacuoles

Answer 24

pump excess water out of the cell

Question 25

central vacuole

Answer 25

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

Question 26

mitochondria

Answer 26

sites of cellular respiration, the metabolic process that uses oxygen to drive the generation of ATP by extracting energy from sugars, fats, and other fuels

Question 27

chloroplasts

Answer 27

found in plants and algae, are the sites of photosynthesis, the process of converting solar energy to chemical energy

Question 28

endosymbiont theory

Answer 28

the theory that states that an early ancestor of eukaryotic cells (a host cell) engulfed an oxygen using nonphotosynthetic prokaryotic cell. eventually, the engulfed cell formed a relationship with the host cell in which it was enclosed, becoming an endosymbiont (a cell living within another cell). indeed, over the course of evolution, the host cell and its endosymbiont merged into a single organism, a eukaryotic cell with the endosymbiont having become a mitochondrion. at least one of these cells may have then taken up a photosynthetic prokaryote, becoming the ancestor of eukaryotic cells that contain chloroplasts

Question 29

cristae

Answer 29

the inner membrane infoldings, gives the inner mitochondrial membrane a large surface area, thus enhancing the productivity of cellular respiration

Question 30

mitochondrial matrix

Answer 30

contains many different enzymes as well as mitochondrial DNA and ribosomes

Question 31

chloroplasts

Answer 31

contain the green pigment chlorophyll along with enzymes and other molecules that function in the photosynthetic production of sugar

Question 32

thylakoids

Answer 32

membranous system in the form of flattened, interconnected sacs

Question 33

granum

Answer 33

each stack of thylakoids in chloroplasts

Question 34

stroma

Answer 34

fluid outside the thylakoids, which contains the chloroplast DNA, ribosomes, and many enzymes

Question 35

peroxisome

Answer 35

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

Question 36

cytoskeleton

Answer 36

a network of fibers extending throughout the cytoplasm

Question 37

motor protein

Answer 37

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

Question 38

mictrotubules

Answer 38

hollow rods constructed from globular proteins called tubulins that shape and support the cell, in all eukaryotic cells

Question 39

centrosome

Answer 39

in animal cells where microtubules grow out from

Question 40

centrioles

Answer 40

a pair within the centrosome, each composed of nine sets of triplet microtubules arranged in a ring

Question 41

flagella and cilia

Answer 41

in some eukaryotic cells, cellular extensions that contain microtubules to help the cell move

Question 42

basal body

Answer 42

in eukaryotic cells, organize the microtubule assembly of a cilium or flagellum and is structurally very similar to a centriole

Question 43

dynein

Answer 43

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

Question 44

microfilaments

Answer 44

thin solid rods built from molecules of actin (a globular protein), can form structural networks when certain proteins bind along the side of such a filament and allow a new filament to extend as a branch

Question 45

cortex

Answer 45

outer region of cytoplasm in a eukaryotic cell lying just under the plasma membrane that as a more gel-like consistency than the inner regions due to the presence of multiple microfilaments

Question 46

myosin

Answer 46

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

Question 47

pseudopodia

Answer 47

a cellular extension of amoeboid cells used in moving and feeding

Question 48

cytoplasmic streaming

Answer 48

a circular flow of cytoplasm, involving interactions of myosin and acting filaments, that speeds up the distribution of materials within cells

Question 49

intermediate filaments

Answer 49

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

Question 50

cell wall

Answer 50

extracellular structure of plant cells, protects the plant cell, maintains its shape, and prevents excessive uptake of water

Question 51

primary cell wall

Answer 51

in plants, a relatively thin and flexible layer that surrounds the plasma membrane of a young cell

Question 52

middle lamella

Answer 52

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

Question 53

secondary plant wall

Answer 53

in plant cells, a strong and durable matrix that is often deposited in several laminated layers around the plasma membrane and provides protection and support

Question 54

extracellular matrix (ECM)

Answer 54

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

Question 55

collagen

Answer 55

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

Question 56

proteoglycan

Answer 56

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

Question 57

fibronectin

Answer 57

an extracellular glycoprotein secreted by animal cells that helps them attach to the extracellular matrix

Question 58

integrin

Answer 58

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

Question 59

plasmodesma

Answer 59

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