Cellular movement

Question 1

1. Microtubule-based motility

Answer 1

• Examples: fast axonal transport
  in neurons; the
  sliding of MTs in cilia and flagella
• Motor protein = kinesin and dynein

Question 1

Cell motility

Answer 1

Movement of a cell or organism through the environment
* Movement of the environment past or through a cell
* Movement of components in the cell
* Or shortening of the cell itself

Question 2

domains of motor protein and functions

Answer 2

Question 3

dyenins functions

Answer 3

cytoplasmic dyneins- moves cargo towards minus ends of MTs
Axonemal dyneins- Activates MT sliding in glagella and cilia

Question 4

Kinesin-1

Answer 4

Dimer; moves cargo towards plus ends of MTs

Question 5

K3

Answer 5

Monomer, movement of synaptic vesicles in neurons

Question 6

K5

Answer 6

Bipolar, tetrameric; bidirectional sliding of MTs during anaphase of mitosis

Question 7

K6

Answer 7

completion of cytokinesis

Question 8

K13

Answer 8

Dimer; destabilisation of plus ends of MTs

Question 9

K14

Answer 9

Spindle dynamics in meiosis and mitosis; moves toward minus ends of MTs

Question 10

Myosin I

Answer 10

Motion of membranes along MFs; endocytosis

Question 11

M II

Answer 11

Slides MFs in muscle; other contractile events such as cytokinesis, cell migration

Question 12

M V

Answer 12

Vesicle positioning and trafficking

Question 13

M VI

Answer 13

Endocytosis; moves towrd minus end of MFs

Question 14

M VII

Answer 14

Base of stereocillia in inner ear

Question 15

M X

Answer 15

Tips of filopodia

Question 16

M XV

Answer 16

Tips of stereocillia in inner ear

Question 17

Kinesin
Movement Along MTs

Answer 17

• Kinesin movement looks like “walking,” with the
  two globular head domains taking turns as the
  front foot.
• Each kinesin molecule exhibits processivity.
• It can move long distances along an M T before
  detaching (100 steps).
• Movement is coupled to the hydrolysis of ATP

Question 18

Kinesin diagram

Answer 18

Question 19

connection to cytoplasmic dynein

Answer 19

Question 20

myosin structure

Answer 20

Question 21

Myosin Functions

Answer 21

• Muscle contraction (muscle myosin Ⅱ)
• Cell movement (nonmuscle myosin Ⅱ)
• Endocytosis (myosin Ⅵ)
• Vesicle transport or other membrane-associated
  events (myosins Ⅰ, Ⅴ)

Question 22

microfilament motility in nonmuscle cells

Answer 22

• Many nonmuscle cells are capable
  of crawling over a substrate using
  lamellipodia and/or filopodia.
• Cell crawling involves distinct
  events:
  1. extension of a protrusion,
  2. attachment to substrate,
  3. and generation of tension, which
  pulls the cell forward

Question 23

Protrusion

Answer 23

Question 24

• Lamellipodium

Answer 24

thin sheet of cytoplasm

Question 25

Filopodium

Answer 25

thin-pointed protrusion

Question 26

attachment

Answer 26

Question 27

Integrins

Answer 27

transmembrane
proteins required for attachment

Question 28

Focal adhesions

Answer 28

integrin dependent attachments

Question 29

Contraction and Detachment

Answer 29

Question 30

Chemotaxis

Answer 30

• Directional movement in response to a graded chemical stimulus

Question 31

Chemoattractant

Answer 31

when a cell moves toward higher
concentrations of the molecule.

Question 32

Chemorepellent

Answer 32

when a cell moves away from higher
concentrations of the molecule