Week 4: Cytoskeleton Structure and Function

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Questions and Answers

What structure is formed by the disassembly and reassembly of cytoplasmic microtubules during mitosis?

Mitotic spindle (correct)

Cytoplasmic network

Actin filaments

Microvilli

What role do microfilaments primarily play in the cell?

Transportation of organelles

Nutrient absorption

Energy storage

Bearing tension and providing mechanical strength (correct)

How are actin filaments linked together in the cytoskeleton?

By myosin proteins

Using actin-binding proteins (correct)

By tubulin dimers

Through motor proteins

Which type of filament is primarily responsible for driving amoeboid movement?

Actin filaments Signup and view all the answers

What is the diameter of microfilaments compared to microtubules?

They are thinner at 7 nm Signup and view all the answers

What is a primary function of intermediate filaments in cells?

Withstanding mechanical stress Signup and view all the answers

What is cytoplasmic streaming?

A circular flow of cytoplasm within cells Signup and view all the answers

Which protein works alongside actin filaments to facilitate muscle contraction?

Myosin Signup and view all the answers

Which of the following describes a stable structural role of microfilaments?

Supporting the plasma membrane Signup and view all the answers

What diameter are microtubules typically?

25 nm Signup and view all the answers

What is the primary structural function of intermediate filaments in cells?

They provide tensile strength and prevent tearing under mechanical stress. Signup and view all the answers

Where are intermediate filaments particularly abundant?

In muscle cells and epithelial cells subject to mechanical stress. Signup and view all the answers

Which type of intermediate filament is specifically found in epithelial cells?

Keratin filaments Signup and view all the answers

What condition is characterized by mutations in the keratin genes leading to fragile skin?

Epidermolysis bullosa simplex (EBS) Signup and view all the answers

What is the function of the nuclear lamina?

To strengthen the nuclear envelope. Signup and view all the answers

What is the approximate diameter range of intermediate filaments?

8–12 nm Signup and view all the answers

How do intermediate filaments contribute to cellular mechanical integrity?

They distribute applied forces to prevent membrane tearing. Signup and view all the answers

Which type of intermediate filament is primarily found in nerve cells?

Neurofilaments Signup and view all the answers

What role does the extracellular matrix (ECM) play in animal cells?

It provides biochemical and structural support to surrounding cells. Signup and view all the answers

Which class of intermediate filaments is found in connective tissue and muscle cells?

Vimentin and vimentin-related filaments Signup and view all the answers

What is the primary role of microtubules in a eukaryotic cell?

They assist in the intracellular transport of organelles and vesicles. Signup and view all the answers

Which statement accurately describes microfilaments?

They are the thinnest components of the cytoskeleton. Signup and view all the answers

What is a key feature of the cytoskeleton?

It interacts with motor proteins to facilitate motility. Signup and view all the answers

What is the diameter range of intermediate filaments?

They have a diameter larger than microfilaments but smaller than microtubules. Signup and view all the answers

Which structure is responsible for the growth of microtubules in an animal cell?

The centrosome Signup and view all the answers

How do microtubules facilitate intracellular transport?

Through rapid growth and shrinkage to create pathways. Signup and view all the answers

What role does the cytoskeleton play in relation to organelles?

It provides anchorage for organelles and cytosolic enzymes. Signup and view all the answers

What is one of the functions of the cytoskeleton related to cell shape?

It helps to support the cell and maintain its shape. Signup and view all the answers

Which protein structures in the cytoskeleton are primarily responsible for vehicle transport?

Microtubules Signup and view all the answers

Study Notes

Cytoskeleton

A network of fibers that provides structure and support for the cell
Interacts with motor proteins to move materials within the cell
Composed of microtubules, microfilaments, and intermediate filaments

Microtubules

Thickest component of the cytoskeleton
Hollow tubes made of tubulin proteins
Responsible for transporting organelles, vesicles, and other cell components
Form mitotic spindles during cell division
Important for cilia and flagella movement

Microfilaments

Thinnest component of the cytoskeleton
Solid rods made of actin proteins
Provide tension resistance and support for the cell's shape
Play a role in cell movement (amoeboid movement, cytoplasmic streaming)
Involved in muscle contraction

Intermediate Filaments

Fibers with diameters between microtubules and microfilaments
Provide tensile strength to withstand stress
Anchor to the plasma membrane at desmosomes
Form the nuclear lamina, which strengthens the nuclear envelope
Found in cells that experience a lot of mechanical stress (muscle cells, epithelial cells)

Extracellular Matrix (ECM)

Provides structural and biochemical support for animal cells
Found outside of the plasma membrane
Plays a role in cell adhesion, migration, and development

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Description

Explore the intricate components of the cytoskeleton, including microtubules, microfilaments, and intermediate filaments. This quiz will test your understanding of their structures, functions, and roles in cellular processes, including movement and support. Perfect for biology students studying cell anatomy and physiology.