Chapter 10

Question 1

cytoskeleton

Answer 1

network of fibers extending throughout cytoplasm; organizes cell’s structures and activities, “roads” for motor proteins to travel on

Question 2

microtubules

Answer 2

“highways”, largest cytoskeleton elements, dynamic, hollow tubes of tubulin dimers that reach out from centrosome; shape and support cell, guide organelle movement, separate cell chromosomes during division

Question 3

motor proteins

Answer 3

“cars” that carry vesicles and other organelles along cytoplasm

Question 4

microfilaments

Answer 4

smallest of cytoskeleton elements, thin, solid rods of molecules of globular actin subunits, under plasma membrane; provide structure, cellular motility by interacting with myosin to produce muscle contraction, amoeboid movement of white blood cells, and cytoplasmic streaming in plant cells

Question 5

intermediate filaments

Answer 5

all around the cell, strong fiber of intermediate filament subunits, only found in the cells of some organisms, inc. vertebrates, static; reinforce cell shape, fix organelles in place

Question 6

plasmodesmata

Answer 6

channels that perforate plant cell walls, allow water and small solutes (sometimes proteins and RNA) to pass from cell to cell

Question 7

desmosomes

Answer 7

anchoring junctions of intermediate filaments

Question 8

tight junctions

Answer 8

prevent leaking of extracellular fluids, “waterproofing”

Question 9

gap junctions

Answer 9

animal cell plasmodesmata, allow for cellular communication through small channels