Lecture 17 - Cytoskeleton & CM: Motor Proteins Flashcards
def: movement of a cell or organism through the environment, movement of the environment past or through the cell, movement of components in the cell
cell motility
def: the shortening of muscle cells, and is a specialized form of motility
cell contractility
what are the 2 eukaryotic motility systems?
- interactions between microtubules and motor proteins kinesics and dyenins
- interactions between actin microfilaments and members of the myosin motor proteins
motor proteins convert chemical energy into __________ _________
mechanical energy
how to molecular motors move?
unidirectionally along their cytoskeletal components in a step wise manner
what are the 3 categories of molecular motors?
- kinesins
- dyneins
- myosins
what do each of the molecular motors use as tracks?
kinesis and dyneins use microtubules and myosin use microfilaments
T or F: motors undergo cycles of ATP hydrolysis, release of ADP + Pi, and acquisition of a new ADP molecule
true
do motor proteins have momentum?
no, they are subject to tremendous friction
are motors processive?
yes they move along a cytoskeletal filament for significant distances
traffic toward the (-) ends of microtubules is considered _____________; toward the (+) end is _______________-
inbound and outbound
def: movement of vesicles and organelles along microtubules
fast axonemal transport
____________ is involved in ATP-dependent transport toward the plus ends (away from the centrosome), called ____________ ________ ____________
Kinesin I, anterograde axonal transport
___________ ______________ moves particles in the opposite direction towards the minus end, called __________ ___________ _____________
retrograde axonal transport
what is the size of steps that kinesis move along the microtubules in
8 nm
what are the 4 parts of a Kinesin I tetramer?
- a globular head region that attaches to MTs (act as ATP hydrolyzing engine)
- a neck region (connect head to stalk)
- a coiled helical stalk region (provide flexibility)
- a light chain region (attaches kinesis to proteins, organelles, or other cargo)