10. Actin monomers (globular actin or G-actin) are organized...

10. Actin monomers (globular actin or G-actin) are organized into linear, double-stranded microfilaments which undergo constant formation by polymerization and destruction by depolymerization, so changes in the structure of actin filaments can occur quickly by balancing or unbalancing these processes. Cytochalasin D is a drug isolated from mushrooms that inhibits actin polymerization, while leaving depolymerization unaffected. The figure shows rates of cytoplasmic streaming in Nitella under control, after addition of Cytochalasin D and then following washout of the drug. Mark on the figure one time each when (i) polymerization > depolymerization and (ii) depolymerization > polymerization of actin filaments. Pond water + Cytochalasin D Rinsed with pond water 60 50 40 30 20 10 0 0 5 10 15 20 25 30 35 Streaming Rate (micrometer/sec) Time (min)

Transcript

00:01 Hello student, here the question is given and the question is about this figure and figure represent the rate of cytoplasmic streaming, cytoplasmic streaming in the case of nitella and this nitella rate of cytoplasmic streaming is under control by addition of this cytocalcin g and this allow after washing with this pond water there is the polymerization and depolymerization will be taking place.

00:39 So we know this here mainly the effect is the actin and this actin monomer or we can say the polymerization and depolymerization is affected by these cytocalcin.

00:55 So the here this polymerization and this in that case double -stranded microfilament undergo the constant formation by the process of this polymerization and this depolymerization is the process is the destruction of this actin filament.

01:20 So changing in the these polymerization and depolymerization is under control by this cytocalcin.

01:31 So here we have to point out the point or we can say the time mark we have to mark where this polymerization is greater than depolymerization.

01:43 So we have to tell this the time where this polymerization is high in compared to this depolymerization and the second one is in at the time where this depolymerization is greater as compared to this polymerization of actin filament.

02:09 So we know the drug which are using in this case this cytocalcin d.

02:19 So this one is going to inhibit polymerization only, polymerization of actin monomer but does not affect depolymerization, depolymerization.

02:53 So in addition of this cytocalcin is going to decrease the amount of polymerized one because they are going to inhibit this polymerization process.

03:06 So the streaming rate, so if it is added then this polymerization is by adding this the polymerization is decreases and ultimately this cytoplasmic streaming is decreases, cytoplasmic streaming in the case of this nitella is also going to be reduced and if we wash out this cytocalcin then the polymerization again is done.

03:42 So after wash out, after wash out the polymerization start again, start again and these going to be balance the amount of these polymerized and depolymerized one...

Question

Please give Ace some feedback