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Questions and Answers

Cell - cell adhesion binds through ______.

CADHERINS

Cell-substrate adhesion binds through ______.

INTEGRINS

Adherens junctions are associated with ______ filaments.

actin

Desmosomes are attached to intermediate ______ filaments.

<p>filament</p> Signup and view all the answers

Focal adhesions are vital for development and involve attachment to the ______.

<p>extracellular matrix</p> Signup and view all the answers

Focal adhesion kinase is involved in signaling for cell ______.

<p>survival</p> Signup and view all the answers

Different integrins are used for different ______ and ECMs.

<p>cells</p> Signup and view all the answers

Inside-out signaling ultimately influences the binding of ______ to integrins.

<p>ligands</p> Signup and view all the answers

The primary function of tight junctions is to provide ______ between epithelial cells.

<p>separation</p> Signup and view all the answers

Adhesion molecules play a crucial role in forming ______ junctions, which are crucial for cell communication.

<p>occluding</p> Signup and view all the answers

The extracellular matrix (ECM) provides structural support and plays a role in ______ pathways.

<p>signaling</p> Signup and view all the answers

In the context of cell adhesion, ______ proteins help connect the extracellular matrix to the cytoskeleton.

<p>linker</p> Signup and view all the answers

In cell signaling pathways, the ______ binds to the receptor to initiate a response.

<p>ligand</p> Signup and view all the answers

Gap junctions close to prevent damage to other ______

<p>cells</p> Signup and view all the answers

Adhesion molecules recognize specific ______ on neighboring cells

<p>ligands</p> Signup and view all the answers

Cells in tissues have specialized contact ______

<p>zones</p> Signup and view all the answers

Desmosomes are involved in more ______ signaling mechanisms

<p>complex</p> Signup and view all the answers

Cell adhesion mechanisms allow for stable and ______ communication

<p>dynamic</p> Signup and view all the answers

Adhesion does not only occur at classical cell ______

<p>junctions</p> Signup and view all the answers

The extracellular matrix provides structural ______ to tissues

<p>support</p> Signup and view all the answers

Cell signaling pathways are crucial for regulating ______ responses in tissues

<p>cellular</p> Signup and view all the answers

In epithelial tissues, junctions like tight junctions provide a ______ barrier

<p>selective</p> Signup and view all the answers

Experimental methods in adhesion research often focus on ______ interactions

<p>protein</p> Signup and view all the answers

Desmosomes connect intermediate filaments from cell to cell using ______ cadherins.

<p>desmosomal</p> Signup and view all the answers

Components of desmosomes include plakins like ______ and plectin.

<p>desmoplakin</p> Signup and view all the answers

Desmosomes contribute significantly to maintaining tissue ______.

<p>integrity</p> Signup and view all the answers

Plakoglobin and plakophillin are classified as ______-like proteins.

<p>armadillo</p> Signup and view all the answers

In stratified epithelia, specific molecules such as desmoyokin are associated with ______.

<p>desmosomes</p> Signup and view all the answers

The main function of desmosomes is to mediate adhesion ______ cells.

<p>between</p> Signup and view all the answers

Cell signaling pathways can be influenced by the components of ______ junctions.

<p>anchoring</p> Signup and view all the answers

Desmosomes are connected to the cytoskeleton via intermediate ______.

<p>filaments</p> Signup and view all the answers

Cell adhesion molecules recognize specific ______ on neighboring cells.

<p>ligands</p> Signup and view all the answers

Experimental methods in adhesion research often involve studying ______ junctions.

<p>cell</p> Signup and view all the answers

What is the primary role of adhesion molecules in multicellularity?

<p>Providing strength and communication between cells</p> Signup and view all the answers

Which of the following best describes the function of epithelial tissues?

<p>They line organs and cavities, and are significant in cancer development.</p> Signup and view all the answers

How do cells typically communicate with each other within tissues?

<p>Through physical contacts and signaling molecules</p> Signup and view all the answers

Which of the following statements about cell signaling is incorrect?

<p>Cell A can only signal Cell B through physical engagement.</p> Signup and view all the answers

What factors may influence the signaling pathways in tissues?

<p>The specific adhesion molecules present</p> Signup and view all the answers

What is the primary role of tight junctions in epithelial cells?

<p>Serving as diffusion barriers and confining transport proteins</p> Signup and view all the answers

How does glucose enter the epithelial cells from the apical surface?

<p>By active transport mechanisms</p> Signup and view all the answers

What mechanism prevents the backflow of glucose from the basal side of the epithelium?

<p>Tight junctions</p> Signup and view all the answers

What is the effect of tight junctions on transport proteins?

<p>They confine transport proteins to specific membrane domains</p> Signup and view all the answers

In which part of the cell does glucose diffuse out after being actively transported in?

<p>Basolateral membrane</p> Signup and view all the answers

Which characteristic distinguishes tight junctions from other junctions?

<p>They act as diffusion barriers</p> Signup and view all the answers

What would likely happen if tight junctions were compromised?

<p>Loss of barrier function, allowing unwanted substances to pass</p> Signup and view all the answers

What structural role do anchoring junctions play in tissues exposed to mechanical stress?

<p>They strengthen cell membranes.</p> Signup and view all the answers

Which proteins are primarily associated with tight junctions?

<p>Claudins and occludins</p> Signup and view all the answers

What can microbes and pathogens do in relation to tight junctions?

<p>Hijack them for their own purposes.</p> Signup and view all the answers

Which of the following components is NOT a major part of anchoring junctions?

<p>Claudins</p> Signup and view all the answers

In anchoring junctions, how are cell membranes primarily reinforced?

<p>By strong membrane-spanning structures tethered to the cytoskeleton.</p> Signup and view all the answers

What type of signaling pathway is influenced by anchoring junctions?

<p>Mechanical stress signaling pathways</p> Signup and view all the answers

What is the key functional role of ZO proteins in tight junctions?

<p>To serve as signaling mediators</p> Signup and view all the answers

Which of the following functions is NOT typically associated with tight junctions?

<p>Facilitating cell communication</p> Signup and view all the answers

What is a consequence of the disruption of tight junctions by pathogens?

<p>Loss of epithelial barrier function</p> Signup and view all the answers

What is the primary role of the intracellular tail of transmembrane adhesion proteins?

<p>To facilitate cell signaling by binding to specific proteins.</p> Signup and view all the answers

Which of the following describes cadherins?

<p>Proteins that mediate cell-cell adhesion in a calcium-dependent manner.</p> Signup and view all the answers

What type of binding do cadherins primarily exhibit?

<p>Homophilic binding with the same type of cadherin.</p> Signup and view all the answers

How does the cytoplasmic tail of adhesion proteins contribute to cellular structure?

<p>By binding to the cytoskeleton and intracellular signaling proteins.</p> Signup and view all the answers

What distinguishes different types of cadherins?

<p>The distinct sequences in their extracellular domains.</p> Signup and view all the answers

What is the significance of the His-Ala-Val sequence in cadherins?

<p>It serves as a site for b-catenin attachment.</p> Signup and view all the answers

Which of the following best describes the role of intracellular proteins in relation to adhesion proteins?

<p>They form a physical connection between adhesion proteins and the cytoskeleton.</p> Signup and view all the answers

What distinguishes cadherins from other adhesion proteins?

<p>Their reliance on calcium for adhesion strength.</p> Signup and view all the answers

Which role does b-catenin play in cadherin-mediated adhesion?

<p>It stabilizes the adhesion junctions by linking cadherins to the cytoskeleton.</p> Signup and view all the answers

Study Notes

Cell Adhesion and Cell Biology

  • Cells form tissues through cell adhesion
  • Multicellularity requires strength in tissues and communication between cells to coordinate
  • Cell-to-cell connections mediate signals and transmit force through cell junctions
  • Cell signaling mechanisms are complex processes that allow cells to respond to their environment

Learning Objectives

  • Students will be able to classify and differentiate various adhesion molecules.
  • Students will understand the differences and similarities in cell adhesion, including specific components, ligands, signaling principles, and cytoskeletal connections.
  • Students will be able to characterize the function of adhesion structures/junctions.
  • Students will be able to identify adhesion molecules, their interactions, and mediating mechanisms.

Epithelia

  • Epithelia line the cavities of organs and produce up to 80% of human cancers.
  • Epithelia act as barriers to protect the body from chemicals, mechanical stress, bacteria, environmental pathogens, and temperature/pH/radiation.
  • Epithelia control the entry and exit of water and nutrients.

Cell Signaling Pathway

  • Ligands/cues, receptors, transducers, and effectors are essential components of a signaling pathway.
  • Adhesion molecules, extracellular matrix molecules, plaque/linker proteins, and signaling molecules (e.g., kinases) participate in cell adhesion processes.

Junctions

  • Junctions are categorized into various types—anchoring, occluding, channel-forming, and signal-relaying.

Anchoring Junctions

  • Anchoring junctions include adherens junctions, desmosomes, and hemidesmosomes.
  • These junctions connect cells, linking to either the extracellular matrix or other partner adhesion proteins.
  • Adherens junctions connect cells via actin filaments— classical cadherins, non-classical cadherins.
  • Desmosomes utilize intermediate filaments and have desmosomal cadherins.
  • Hemidesmosomes anchor cells to the extracellular matrix via intermediate filaments and integrins.

Occluding Junctions (Tight Junctions)

  • Tight junctions form barriers, regulating the passage of small molecules and electrolytes.
  • Key proteins include claudins and occludins.
  • Tight junctions are responsible for preventing backward flow of glucose.

Gap Junctions

  • Gap junctions permit the passage of small molecules and electrolytes, allowing for direct electrical communication between cells.
  • Gap junctions are made up of connexins.
  • Calcium and pH regulate gap junction closure.
  • Gap junctions are essential for cellular signaling networks.

Hemidesmosomes

  • Hemidesmosomes connect cells to the extracellular matrix, essential for skin integrity.
  • Defective hemidesmosomes lead to skin blistering diseases.

Focal Adhesions

  • Focal adhesions are crucial for cell migration, cell spreading, and development.
  • Integrins serve as receptors, interacting with the extracellular matrix.
  • Focal adhesion kinase (FAK) plays a vital role in the dynamic assembly and disassembly of focal adhesions.

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Adhesion in Epithelia BS31004 PDF

Description

Test your knowledge on cell adhesion and its critical role in multicellularity. This quiz covers key concepts about adhesion molecules, signaling mechanisms, and the importance of epithelial tissues. Dive deep into how cells communicate and coordinate through adhesion structures.

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