Cytoskeleton

Question 1

Actin filaments (aka microfilaments)

Answer 1

Flexible, thin fibers

Usually underneath cell membrane

Mobility, membrane activity

Question 2

Intermediate filaments

Answer 2

Tough fibers

Many different proteins

Widely varying locations and functions

Question 3

Microtubules

Answer 3

Rigid tubes

Throughout cell

Stability, transport, organization

Polar, polymerize on + end and depolymerize on - end

Question 4

Tubulin

Answer 4

Alpha and beta subunits form tubulin

MTs are multiverse (“polymers”) of a-b dimers

Catalyzes hydrolysis of GTP (GTPase)

Question 5

Centrosome

Answer 5

Microtubule organizing center in animals

Made of centrioles (MTs) and other proteins

Nucleates new ants and anchors and organizes MTs

Organizes mitotic spindle in dividing cells

Question 6

Actin polymerization/depolymerization cycle

Answer 6

Polar

Polymerize + end, depolymerize on -end

Slowly catalyzes ATP hydrolysis (ATPase)

Question 7

Amoeboid movement (pseudopod)

Answer 7

Initiated by acting polymerization

Question 8

Kinesin

Answer 8

+ end oriented

Ante-retrograde (goes OUT)

Requires ATP/is ATPase

Question 9

Dynein

Answer 9

Minus (-) end directed

Retrograde (goes IN)

Requires ATP/is ATPase

Question 10

Sarcomere

Answer 10

Contractile unit of skeletal muscle

Question 11

Myosin

Answer 11

+ end directed motor

Requires ATP

is an ACTIN motor

ATP required for RELEASE of myosin from actin filament