cells part 3

Question 1

microfilaments

Answer 1

-smallest, thinnest
-help a cell or parts of a cell to move
-determine cell shape
-made of protein actin
-have distinct ends: plus and minus
-form long helical chains

Question 2

microtubules

Answer 2

long, hollow cylinders; form a rigid internal skeleton; act as a framework for motor proteins; made from dimers of the protein tubulin; can change length rapidly by adding or losing dimers at plus or minus ends; ex of quaternary structure

Question 3

cilia

Answer 3

short, hundreds on one cell, move stiffly to propel the cell or move fluid over a cell

Question 4

flagella

Answer 4

longer, usually one or two present, movement is snakelike

Question 5

motor proteins

Answer 5

moves vesicles or organelles from one part of a cell to another

Question 6

kinesin

Answer 6

-is - to +
-binds to a vesicle and “walks” it along by changing shape
-move materials toward the plus end

Question 7

dynein

Answer 7

+ to -; move materials toward the minus end

Question 8

first eukaryote

Answer 8

appears in the fossil record 2.7 billion years ago

Question 9

symbiosis

Answer 9

living together

Question 10

theory of endosymbiosis

Answer 10

proposes that mitochondria and chloroplasts arose when one cell overtook another cell

Question 11

plasma membrane

Answer 11

permeable

Question 12

vesicles

Answer 12

pinched off bags

Question 13

cytoskeleton

Answer 13

-supports and maintains cell shape
-holds organelles in position
-moves organelles
-involved in cytoplasmic streaming
-interacts with extracellular structures to hold cells in place
-composed of three types of filaments

Question 14

intermediate filaments

Answer 14

tough, ropelike protein structures; anchor cell structures in place; thick and rigid structure