Chapter 6

Question 1

cell theory

Answer 1

cells are small for the proper cell surface, volume ratio

Question 2

prokaryotes

Answer 2

outer membrane, no compartmentalization, DNA kept in region but not separate from rest of cell, all cell processes occur in cytosol

Question 3

eukaryotes

Answer 3

many internal membrane bound structures (organelles)

Question 4

endosymbiont theory

Answer 4

internal membrane bound structures originated from mitochondria and chloroplasts are double membrane structures and have their own genomes and ribosome: likely were separate cells long ago

Question 5

nucleus

Answer 5

nucleolus, nuclear envelope, nuclear pores

Question 6

DNA

Answer 6

chromatin, chromosomes, ribosomes

Question 7

endoplasmic reticulum (ER)

Answer 7

rough ER for protein synthesis, smooth ER for lipid synthesis

Question 8

golgi

Answer 8

part of endomembrane system, sorts proteins that move through (also adds certain types of carbohydrates)

Question 9

endosome

Answer 9

part of endomembrane system

Question 10

lysosome

Answer 10

recycling center

Question 11

mitochondria

Answer 11

cellular respiration occurs, structure includes: outer membrane, inner membrane, matrix, intermembrane space

Question 12

chloroplast

Answer 12

photosynthesis. structure includes: outer and inner membranes, stroma, thylakoids, grana

Question 13

peroxisome

Answer 13

contains enzymes and peroxide to detoxify harmful substances

Question 14

vacuole

Answer 14

water storage in plants, similar to lysosome in fungi

Question 15

cytoskeleton

Answer 15

supports structure and maintains shape, composed of: large microtubules, middle size intermediate filaments, small microfilaments (actin). Made of actin monomers that bind to ATP, actin forms into filaments with + end (more polymerization) and - end (depolymerization).

Question 16

ATP hydrolosis

Answer 16

makes filaments start to destabalize and fall apart

Question 17

actin

Answer 17

useful in cell movement, forms networked structures under cell surface and form specialized structures like microvilli (on intestine and kidney cells to help move fluids around)

Question 18

intermediate filaments

Answer 18

made of several types of subunits, all form rope like bundles, very strong/stable, hold cell structures in place

Question 19

microtubules

Answer 19

strong, hollow, made of alpha and beta dimers, polarized, found in cytoplasm, support cell structure and move chromosomes and other organelles, moving vesicles along tracks pulling chromosomes apart during mitosis

Question 20

GTP

Answer 20

needed for protein synthesis

Question 21

intermediate filaments

Answer 21

remains constant, supportive and stiff, different proteins, anchorage of cell, resist tension and maintain cell shape

Question 22

flagella (microtubules)

Answer 22

9 doublets around 2 singlets, all tubules connected by MT-binding proteins (some used for movement), formed by microtubles

Question 23

cilia (microtubules)

Answer 23

same MT structure, movement of cell, formed by microtubules. whiplike motion

Question 24

motor proteins

Answer 24

walk along cytoskeletal structures

Question 25

myosins

Answer 25

actin motor proteins (require ATP hydrolosis)

Question 26

mt (microtube) motor protein

Answer 26

kinesin and dynein (require ATP. hydrolosis)

Question 27

dynamic instability

Answer 27

shown by actin and microtubules and due to the rapid polymerization at one end and depolymerization at the other

Question 28

treadmilling

Answer 28

filament/tubule changes its length while individual subunit stays still, still looks like subunit is moving

Question 29

actin

Answer 29

a protein that helps cells move, maintain their shape, and contract muscles. It's the most abundant protein in most eukaryotic cells.

Question 30

microvilli

Answer 30

actin filaments form this, tiny, finger-like projections on the surface of certain cells that function to significantly increase the cell's surface area,

Question 31

plasmodesmata

Answer 31

exchange of material across cell wall in plants

Question 32

extracellular matrix

Answer 32

proteins, glycoproteins, and proteoglycans secreted by cells to created an environment that allows communication. between nearby cells. carbs on proteogylcans and glycoproteins attract water to maintain fluidity

Question 33

cell junctions

Answer 33

allow cells to stay together to work together

Question 34

plasmodesmata

Answer 34

in plants, channels span plasma membrane and cell walls and allow passage of materials/nutrients

Question 35

tight junctions

Answer 35

keep cells tightly together and prevent material from passing between them (useful in skin, our protective barrier against the environment)

Question 36

desmosomes

Answer 36

protein structures inside cells and outside cells that interlock with adjacent cell, have intermediate filaments attached in cytoplasm. useful for keeping cells together in areas that are prone to physical/mechanical stress

Question 37

gap junctions

Answer 37

pores through two adjacent cells that allow passage of materials, can open and close and be specific for certain molecules