Concept explainers
To review:
Match the terms microtubules, intermediate filaments, or actin filaments with the most closely related descriptions given below:
(a) Thinnest cytoskeletal filaments; are associated with motor protein myosin.
(b) Consists of proteins twisted together in a rope-like form
(c) Allow certain cells to “crawl” and change the shape and the size of the cell
(d) Consists of protein subunits surrounding a hollow core
(e) Help a cell to resist mechanical stress
(f) Grow from the cell’s centrosome
Introduction:
The microtubules, intermediate filaments, and the actin filaments belong to the cytoskeleton of the cell. The cytoskeleton is composed of the different types of the protein filaments, which are organized according to their functions.
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Human Anatomy & Physiology (2nd Edition)
- Below are three statements - two of which are truths and one is a lie. Which of the following statements is a lie? Select one: a. Keratin - an intermediate filament, is classified as Types I and II or acid and base keratins. b. Microfilaments have two structures called bundles and networks. The former is used for movement inside the cell while the latter is for intercellular communication. c. Kinesin is a microtubule motor protein that helps in the transportation of cellular material essential to cell function and moves towards the minus end motor. Clear my choicearrow_forwardWhich of the following is NOT an example of microtubule-based motility? A. ciliary movement B.contractile ring of cleavage furrow C. pigment granule transport in fish scales D.axonal transport in neurons QUESTION 33 You are studying the role of microtubules and microfilaments in cell motility. You treat fibroblasts with cytochalasin, which inhibits microfilaments, or colchicine, which inhibits microtubules, and observe the following: In controls, the cells migrate in a directed way, elongating as they go. With cytochalasin treatment, the cells completely stop migrating while with colchicine treatment, the cells attempt to migrate in several directions at once. The best conclusion for this is: A Cytochalasin prevents cell migration and colchicine prevents directed cell migration. B. Microfilaments are necessary for cell migration and microtubules are necessary for directionality of migration. C. Microfilaments are necessary for cell migration and microtubules are sufficient for…arrow_forwardName the cytoskeletal element (actin microfilaments, intermediate filaments, or microtubules) for each of the following.(a) give the cell its shape(b) resist tension placed on a cell(c) radiate from the centrosome(d) interact with myosin to produce contraction force(e) are the most stable(f) associated with kinesins and dyneins(g) associated with the motor protein myosinarrow_forward
- A melanosome (type of vesicle containing the pigment melanin) is transported towards the nucleus of the cell. The hydrolysis of ATP is involved with this movement. Identify the most likely motor protein and cytoskeletal filament involved with this transport. a. Myosin, microtubules b. Kinesin, actin filaments c. Dynein, actin filaments d. Dynein, microtubules e. Kinesin, microtubules f. Myosin, actin filamentsarrow_forwardGive two examples of biological functions that are enabled by microfilaments or microtubules together with associated motor proteins.These could be whole cell functions or functions within the cell.arrow_forward45. Which of the following accurately represents how intermediate filaments differ from actin filaments and microtubules? Only intermediate filaments ... … a) interact with extracellular matrix components. b) associate with motor proteins. c) are composed of the same protein subunits in all cells. d) are polar with plus and minus ends. e) play a purely structural role.arrow_forward
- if you visualize the cytoskeleton of a cell that is expanding in one direction, you typically observed a strong orientation of the cytoskeleton. Please answer the following three questions. a. Would the cytoskeleton be oriented parallel or perpendicular to the direction of cell expansion? b. Would the cellulose fibers in the cell wall be parallel or perpendicular to the cytoskeleton? c. Explain why cytoskeleton, cellulose fibers, and direction of cell expansion have the relationship mentioned in a and b?arrow_forwardMicrotubules are polar filaments; that is, one end is different from the other. What is the basis for this polarity, how is polarity related to microtubule organization within the cell, and how is polarity related to the intracellular movements powered by microtubule-dependent motors?arrow_forwardActin and microtubules have polarity, intermediate filaments have no polarity. What is the main consequence of this difference?arrow_forward
- a) Are actin filaments subject to the same "dynamic instability" as microtubules? Yes or no? b)Explain how both actin and microtubules polymerize and depolymerize.arrow_forwardBriefly describe how the components of the cytoskeleton filaments get to the right location in the cell for filament formation.arrow_forwardWhich of the following statements are true for both actin and tubulin: a. Both actin and tubulin filaments are hollow. b. Both actin and tubulin are structural proteins capable to form filaments that can grow from both (+) and (-) ends. c. Both actin and tubulin require GTP for polymerization into filaments. d. Both actin and tubulin require ATP for polymerization into filaments.arrow_forward
- Human Physiology: From Cells to Systems (MindTap ...BiologyISBN:9781285866932Author:Lauralee SherwoodPublisher:Cengage Learning