8.592 - HST.452J (Spring 2022)
Statistical Physics in Biology
Lecture 18
(Please note that lecture is being recorded)
8.592 in 4-265 on 03/30/2022 at 2:30PM
Molecular Motors
Molecular motors
:
Kinesin
and
Dynein
move in opposite directions along microtubules
consuming ATP
Myosin
moves on
actin filaments
(
offline animation
) [
youtube
]
Motion of kinesin on a microtubule (Vale lab)
(
offline animation
)
General scheme of motor transport:
Asymmetry for directionality
Rectification of fluctuations by consumption of energy
Motion in a noisy environment
Feynman's ratchet and pawl
: (
youtube
)
Simulation of a Brownian motor
From the
web-page of George Oster
:
"Ratchets, power strokes, and molecular motors,"
H. Wang & G. Oster, Appl. Phys. A
75
, 315 (2002).
"The physics of molecular motors,"
C. Bustamante, D. Keller, & G. Oster, Acc. Chem. Res.
34
, 412, (2001),
Asymmetric hopping models:
"The force exerted by a molecular motor,"
M.E. Fisher & A.B. Kolomeisky, PNAS
96
, 6597 (1999).
Multiple internal states
Solution with two internal state
Einstein force, stalling force
Efficiency at maximum power
;
T. Schmiedl & U. Seifert EPL
(
Lecture notes
)
Some related links
Kinesin Home Page
Dynein Home Page
Kinesin Motors - the Movies
Vale lab movies (e.g. MT gliding)
The inner life of a cell
Capturing and viewing single molecules:
Optical tweezers
Fluorescent light microscopy
Cell Motion
Brownian motion
: (
offline
)
Movies of
milk droplets in water
,
Brownian motion simulation
Langevin description
Fokker-Planck descrition
Thermal equilibrium and the Einsten relation
Lecture notes on
Dissipative Dynamics
Crawling cells
Crawling Neutrophil Chasing a Bacterium
Actin-based motility
(Listeria)
More from the
Theriot lab movie collection
Swimming cells:
Life at Low Reynolds Number
(E.M. Purcell)
The scallop theorem: impossibility of reciprocal motion
Flagellar rotary motion (efficiency)
Chemotaxis by runs and tumbles- why?
Some related links
Cell Locomotion
Some parameters for diverse
Cell Motion
"The efficiency of propulsion by a rotating flagellum,"
E.M. Purcell, PNAS
94
, 11307 (1997)
.
"
Motile behavior of bacteria
," (Physics Today, Howard Berg).
8.592
lecture- last update 3/27/22 by M. Kardar