Question

Actin filaments: How do they grow? Which end grows faster? Does ATP hydrolysis reduce or increase stability of the polymer? Is free actin concentration is high, what happens?

a) Grow by polymerization, faster at the minus end, ATP hydrolysis increases stability, High concentration leads to depolymerization
b) Grow by depolymerization, faster at the plus end, ATP hydrolysis reduces stability, High concentration leads to polymerization
c) Grow by polymerization, faster at the plus end, ATP hydrolysis reduces stability, High concentration leads to depolymerization
d) Grow by depolymerization, faster at the minus end, ATP hydrolysis increases stability, High concentration leads to polymerization

Answer 1

Actin filaments grow by polymerization, with the plus end growing faster. ATP hydrolysis reduces the stability of the actin polymer. High concentration of free actin monomers leads to depolymerization.

Step-by-step explanation:

Actin filaments grow by polymerization, with new G-actin monomers joining the plus end of the existing polymer. The plus end of the actin filament grows faster compared to the minus end. ATP hydrolysis reduces the stability of the actin polymer because when ATP is hydrolyzed to form ADP, it weakens the binding strength of the monomers in the chain. When the concentration of free actin monomers is high, it leads to depolymerization of the actin filaments.