Cell Biology: Cilia and Microvilli Functions

Questions and Answers

What is the function of microvilli?

Propel material over surfaces

Increase the cell's surface area (correct)

Absorb nutrients

None of the above

How do cilia and flagella function?

Increase surface area

Actively beat to propel material (correct)

Absorb nutrients

None of the above

What are stereocilia?

Unusual microvilli that are unrelated to cilia.

Microvilli are covered by extensions of the ________.

plasma membrane Signup and view all the answers

Microvilli have bundles of thin __________ in their cores.

actin Signup and view all the answers

What does the 'terminal web' do?

Anchors microvillar filaments Signup and view all the answers

Fluid-absorbing cells in the male reproductive tract have __________ specializations called stereocilia.

unusual Signup and view all the answers

Where is cilia found?

On cells that move material through a tube or across a surface. Signup and view all the answers

Cilia contain a core of _________.

microtubules Signup and view all the answers

________ have pairs of centrioles at their core.

Basal bodies Signup and view all the answers

The microtubules in the core of the __________ are arranged in a '(9+2)' configuration.

cilium Signup and view all the answers

The cilium's core is called an _______.

axoneme Signup and view all the answers

List three differences between cilia and microvilli.

<ol> <li>Cilia are actively motile while microvilli are not. 2. Cilia have cores built on microtubules, while microvilli have cores built on actin filaments. 3. Cilia are wider and longer/taller than microvilli.</li> </ol> Signup and view all the answers

Study Notes

Microvilli Function

Microvilli enhance cell surface area, crucial for absorption and transport processes.
Commonly found on epithelial cells lining intestines, aiding in nutrient absorption.

Cilia and Flagella Function

Cilia and flagella actively beat to move material across surfaces or through tubes.

Stereocilia

Stereocilia are unique structures resembling microvilli but are unrelated to cilia.
They consist of elongated, branched microvilli, which serve to increase the cell's surface area.

Structure of Microvilli

Microvilli are encased by extensions of the plasma membrane.
The structure contains bundles of actin filaments that stiffen and maintain their extended form.

Terminal Web

The terminal web anchors microvillar filaments to the apical cytoplasm of cells.
It comprises intermediate filaments, providing structural support.

Stereocilia Location

Found in fluid-absorbing cells within the male reproductive tract.
Act as specializations with typical actin cores to enhance surface area.

Cilia Location

Present on cells that transport materials through tubes or across surfaces.
Notably motile and located on epithelial cells in trachea, oviduct, and brain ventricles.
Flagella, similar to cilia in structure and function, are located on spermatozoa.

Structure of Cilia

Cilia are larger than microvilli, containing a core structure composed of microtubules.

Basal Bodies

Basal bodies feature pairs of centrioles that anchor and stabilize microtubules, preventing depolymerization.

Configuration of Microtubules

The core microtubules in cilia and flagella exhibit a "(9+2)" arrangement, indicating nine outer doublet microtubules surrounding two central microtubules.

Axoneme

The core structure of a cilium is termed the axoneme, integral to its function.

Cilia vs. Microvilli

Cilia are motile, whereas microvilli lack motion.
Cilia are structurally supported by microtubules; microvilli utilize actin filaments.
Cilia are generally wider and taller than microvilli.

Description

Explore the critical functions of cilia and microvilli in cellular biology through this quiz. Learn how these structures enhance cell surface area and facilitate movement across membranes. Perfect for students studying cell structure and function.