26 Questions
What is the diameter of microtubules?
25nm
Which protein filament is thinner than microtubules?
Actin filaments
What are microfilaments made from?
Actin
What are intermediate filaments made from?
Keratin
Which cytoskeletal protein filament is described as long tubes?
Microtubules
What is crucial for the function of many highly specialized cells?
Segregation of particular structures within certain parts of the cell
Which cellular process involves the movement of molecules and organelles within the cell?
Transport
What aspect of the cytoskeleton allows it to respond to changes in cell shape?
Dynamic increase and decrease in internal structures
What is NOT a function of the cytoskeleton?
Segregation of organelles within the cell
In which type of cells is the super-elongated form like neurons often observed?
Highly specialized cells
Why do cells need to be motile?
To secrete extracellular matrix (ECM) proteins
What is the primary function of motile cells in host defense?
Constantly searching for pathogens
What contribution does uncontrolled cell migration make to cancer?
Formation of tumors
How does the cytoskeleton support the cell shape?
By shifting and rearranging
What is a function of the cytoskeleton besides providing cell shape?
Transporting substances within the cell
Which cellular component is responsible for cells being able to sense their environment?
Small filopodia
What is the main function of the cytoskeleton within a cell?
Maintaining cell architecture and providing a transport system
Which of the following is NOT a component of the cytoskeleton mentioned in the text?
Endoplasmic reticulum
Which group of proteins are responsible for cell movement mentioned in the text?
Kinesin, dynein, and myosin
How does the cytoskeleton contribute to the rigidity of a cell?
By providing a structural framework for cell support
Which evolutionary event was accompanied by the emergence of a system that positioned and anchored cell organelles?
Compartmentalization of cell organelles
What is the function of filaments in the cytoskeleton?
Transport cargoes
How do accessory proteins contribute to the cytoskeleton?
Cross link filaments with other proteins
What does the cytoskeleton primarily consist of?
Protein filaments and motor proteins
Which term best describes the 3D structure formed by protein filaments in the cytoskeleton?
Meshwork
Besides providing rigidity, what other function do the filaments in the cytoskeleton serve?
Act as trackways for transport
Study Notes
Cytoskeleton: Structure and Function
- The cytoskeleton is composed of three groups of protein filaments: microtubules, intermediate filaments, and actin filaments, which vary in size (25nm, 8nm, and 10nm external diameter, respectively).
- These protein filaments are polymers made up of protein sub-units.
Functions of the Cytoskeleton
- The cytoskeleton provides structural support to the cell, allowing it to change shape and move.
- It plays a crucial role in the segregation of internal cellular elements, such as organelles or proteins, and their relative position to one another.
- The cytoskeleton enables transport of molecules and organelles within the cell, as well as the movement of the cell as a whole.
Importance of Cell Motility
- Cell motility is essential for various biological processes, including:
- Neutrophil (macrophage) migration to chase bacteria
- Cell migration during development to reach defined locations
- Host defense against pathogens
- Wound healing through the secretion of extracellular matrix (ECM) proteins
Why Study Cell Migration?
- Uncontrolled cell migration contributes to several pathologies, including:
- Vascular diseases
- Chronic inflammatory diseases
- Cancer (tumor formation and metastasis)
Basis of Cell Migration
- The cytoskeleton, composed of fibers that dynamically reorient, shrink, and grow, is the basis of cell migration.
- This mechanism allows for:
- Axon growth and connection in neurons
- Muscle cell contraction and force production
- Cell division during mitosis
- Formation of filopodia to sense the environment
Cytoskeleton and Cell Architecture
- The cytoskeleton forms the architecture and transport system of the cell, providing:
- Structural support and shape
- Transport of cargo-filled vesicles, individual molecules, and cell organelles
- Positioning and anchoring of cell organelles
Cytoskeleton: Movers and Shapers
- The three main groups of shapers (protein filaments) are:
- Microtubules
- Intermediate filaments
- Actin filaments
- The three main groups of movers (motor proteins) are:
- Kinesin
- Dynein
- Myosin
Test your knowledge on why cells need to be motile and the importance of studying the basics of cell movement. Explore key concepts such as cell migration in development, host defense, and wound healing, as well as the implications of uncontrolled cell migration in various pathologies.
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