Question

ose the item in column 2 that best matches each item in column 1. axonemal microtubules nucleation treadmilling desmin EB1 Arp2/3 complex myosin subfragment 1 (S1) tropomodulin gelsolin microvilli lamin phosphoinositides MAPs plectin lamin A. anchors spectrin filaments to red blood cell membrane B. hemidesmosome C. crosslinks microtubules to intermediate filaments D. inhibits microtubule assembly E. forms scaffold underlying nuclear envelope F. stabilizes and organizes microtubules G. is in cilia and flagella H. formation of tubulin oligomers I. binds to microtubule plus ends J. prevents loss of subunits from filament minus end K. connects crisscrossing actin filaments into 3D networks L. binds to profilin and CapZ M. curves bacterial cells N. increase cell surface area O. decorates actin microfilaments P. nucleates microtubule branches Q. nucleates actin filament branches R. assembly and disassembly on opposite ends of the same filament S. breaks and caps actin filaments T. keeps muscle myofibrils in register U. desmosome

Answer 1

Answer:

• axonemal microtubules: (G) is in cilia and flagella
• nucleation: (H) formation of tubulin oligomers
• treadmilling: (R) assembly and disassembly on opposite ends of the same filament
• desmin: (T) keeps muscle myofibrils in register
• EB1: (I) binds to microtubule plus ends
• ARP2/3 complexes: (P) nucleates actin filament branches
• myosin subfragment 1 (S1): (O) decorates actin filaments
• tropomodulin: (J) prevents loss of subunits from filament minus ends  
• gelsolin: (S) breaks and caps actin filaments
• microvilli: (N) increase cell surface
• filamin: (K) connects crisscrossing actin filaments into 3D networks
• phosphoinositides: (L) binds to profilin and CapZ
• MAPs: (F) stabilizes and organizes microtubles
• plectin: (C) crosslinks microtubles to intermediate filaments
• lamin: (E) forms scaffold underlying nuclear envelope.

Explanation:

• Axonemal microtuble: an axoneme is a microbule based cytoskeleton structure of a eukaryotic cilium or flagellum. It provides motility, and also gives support to the structure.
• nucleation: it is a process where interaction of several tubulin molecules lead to the formation of microtubules seed. This process occurs spontaneously in purified tubulin solutions.
• treadmilling: is a phenomenon, that especially occurs in actin filaments and microtubules,where continuous removal of actin monomers from pointed ends of filament occur and their reincorporation at the other ends
• desmin: it is a specific protein found in muscle that integrates sarcolemma, Z disk and nuclear membrane in sarcomeres and regulates sarcomere architecture
• EB1: its a plus-end tracking protein that binds to plus end of microtules and modulates their dynamics and interactions with intercellular organelles.
• ARP2/3 complex: its a seven-subunit central actin nucleator that binds  to the side of filament to promote new filament growth as a branch thus forming a complex actin network.
• myosin subfragmnet (S1): S1 is the head fragment of myosin globular heads, that contains the ATPase and actin-binding activities of myosin.
• tropomodulin: it is a protein that binds and caps the pointed ends(or minus ends) of actin filaments thereby regulating its length in muscle cells as well as non muscle cell.
• gelsolin: is an actin binding protein that binds and caps actin filament(responsible for assembling and disassembling of filaments)
• microvilli: found in the apical surface of epithelial cells or the stereocillia, spine like protrusions, that increase the cell surface area for diffusion upto 100 times.
• filamin: is an actin binding protein that holds two filaments at large angles.
• phosphoinositides: it regulates the activities of many actin binding proteins and have the tendency to bind with profilin and CapZ(its a capping protein that caps the barbed ends of actin filament)
• MAPs: microtubules associated protein or MAPs binds to and stabilizes microtubules lattice. MAPs have repeating domains that allow eash MAP molecule to associate with more than one tubulin dimer.
• plectin: a structural protein of the cytoskeleton that maintains tissue integrity
• lamin: are fibrous protein of type V intermediate filaments that provide structural function and transcriptional regulation in the cell nucleus.