Chapter 14

Question 1

kinesins and dyneins

Answer 1

microtubule associated motor proteins

Question 2

fast axonal trasport

Question 3

axoplasm

Answer 3

cytosol of axons

Question 4

anterograde (forward) axonal transport

Answer 4

kinesin mediates transport from the cell body down the axon to the nerve ending

Question 5

retrograde (backward) axonal transport

Answer 5

dynein mediates transport toward the minus end of the MT

Question 6

heavy chains of kinesines contain….

Answer 6

globular domains that attach to microtubules and are involved in hydrolysis of ATP

Question 7

how kinesin-1 moves

Answer 7

one of two globular domains moves forward to make an attachment to a new B-tubulin subunit

Question 8

dyneins can be divided into two categories

Answer 8

cytoplasmic and axonemal

Question 9

cytoplasmic dyneins move…

Answer 9

towards the minus end of MT

Question 10

dynactin

Answer 10

a protein complex cytoplasmic dyneins associate with, helps link to cargo

Question 11

axonemal dyneins function where?

Answer 11

in the cilia and flagella

Question 12

endomembrane system

Answer 12

an elaborate transportation system of vesicles and membrane organelles

Question 13

cilia

Answer 13

cilium, tend to occur in large number on the surface of cells, unicellular and multicellular eukaryotes

Question 14

flagella

Answer 14

flagellum, move cells through a fluid environment, much longer than cilia and limited to a few per cell

Question 15

axoneme

Answer 15

a structure shared by cilia and flagella

Question 16

transition zone

Answer 16

the arrangement of microtubules in the basal body takes on the pattern characteristic of the axoneme

Question 17

basal body

Answer 17

nine sets of tubular structures

Question 18

“9 + 2” pattern

Answer 18

nine outer doublets of tubules and two additional microtubules in the center

Question 19

central pair

Answer 19

the two additional microtubules in the “9 + 2” pattern

Question 20

primary cilia

Answer 20

specialized used in sensory structures, often have a “9 + 0” structure

Question 21

A tubule

Answer 21

one complete microfilament, 13 protofilaments

Question 22

B tubule

Answer 22

one incomplete microfilament, 10/11 protofilaments

Question 23

sidearms

Answer 23

project from each of the A tubules counterclockwise, consist of axonemal dynein

Question 24

interdoublet links

Answer 24

thought to limit the extent to which doubleets can move with respect to each other

Question 25

radial spokes

Answer 25

project inward from the 9 MT doublets, thought to be important in translating the sliding motion of adjacent doublets

Question 26

Evidence dynein arms provide the driving force for axonemal bending

Answer 26

1. when it is removed from isolated axonemes, the arms disappear from outer doublets, and lose ability to hydrolyze ATP/capacity to beat
2. in some mutant, flagella are present but non-functioning due to their flagella lacing dynein arms, radial spokes, or the central pair