tissue adaptation

• What are the repeating units of glycosaminoglycans (GAGs) in connective tissue?

  • $D-glucuronic\ acid$
  • $N-acetylgalactosamine$

  
• What are the common types of glycosaminoglycans (GAGs) in connective tissue?

  Hyaluronate, chondroitin sulfate, and keratan sulfate

  
• How do proteoglycans contribute to the structure of connective tissues?

  • They consist of a core protein with multiple GAG chains attached.
  • The GAG chains are extended to form a brush-like structure.
  • They bind water and maintain tissue hydration.

  
• What type of bond links GAG chains to the core protein in proteoglycans?

  Covalent bond

  
• Why are GAG chains extended in proteoglycans?

  To increase surface area for interaction with water and other molecules

  
• What role do proteoglycans play in maintaining tissue hydration?

  They bind water to maintain tissue hydration

  
• How does the attachment of GAG chains to the core protein influence the properties of proteoglycans?

  It determines their ability to interact with water and other molecules

  
• What are the repeating units of chondroitin sulfate?

  • $D-glucuronic\ acid$
  • $N-acetylgalactosamine$

  
• What are the repeating units of keratan sulfate?

  • $Galactose$
  • $N-acetylglucosamine$

  
• What role does the link protein play in proteoglycans?

  • It links proteoglycan aggregates to hyaluronic acid.
  • It facilitates the assembly of large proteoglycan complexes.

  
• What are the structural features of hyaluronic acid?

  • $D-glucuronic\ acid$
  • $N-acetylgalactosamine$
  • Long, unbranched polysaccharide chain.

  
• What molecule does the link protein connect to hyaluronic acid in proteoglycan aggregates?

  Core protein of proteoglycans

  
• What type of glycosaminoglycan (GAG) is shown in the first image?

  Chondroitin sulfate

  
• What monosaccharide unit is present in chondroitin sulfate that is absent in keratan sulfate?

  1. iduronic acid (IdUA)

  
• What is the role of the sulfate group in chondroitin sulfate?

  It increases the molecule's negative charge to enhance interactions with cations and structural properties

  
• What is the repeating disaccharide unit in chondroitin sulfate?

  1. glucuronic acid (GlcUA) and N-acetylgalactosamine (GalNAc)

  
• How does the linkage between GlcUA and GalNAc differ in chondroitin sulfate compared to keratan sulfate?

  Chondroitin sulfate has a $\beta-1,3$ linkage while keratan sulfate has a $\beta-1,4$ linkage

  
• If you were designing a GAG for a specific tissue application, what structural features of chondroitin sulfate might you incorporate to enhance its efficacy?

  Increase sulfate group density or adjust the linkage types to enhance efficacy for specific tissues

  
• What are the key differences between chondroitin sulfate and keratan sulfate?

  • Disaccharide units: Chondroitin sulfate has GlcUA and GalNAc; Keratan sulfate has Gal and GlcNAc
  • Linkages: Chondroitin sulfate has $\beta-1,3;$ Keratan sulfate has $\beta-1,4$
  • Uronic acids: Chondroitin sulfate contains IdUA; Keratan sulfate lacks IdUA
  • Sulfate groups: Chondroitin sulfate has more sulfate groups

  
• What type of glycosaminoglycan (GAG) is shown in the second image?

  Keratan sulfate

  
• What monosaccharide unit is common to both chondroitin sulfate and keratan sulfate?

  1. acetylgalactosamine (GalNAc)

  
• What are the structural features of keratan sulfate?

  • Repeating disaccharide units: Gal and GlcNAc
  • $\beta-1,4$ linkage
  • Lacks uronic acids
  • Variable sulfate content

  
• What is the function of keratan sulfate?

  Structural support in cartilage, cornea, and other connective tissues

  
• Compare and contrast chondroitin sulfate and keratan sulfate in terms of their structural components and functions.

  • Structural Components:
  • Chondroitin sulfate: GlcUA and GalNAc, $\beta-1,3$ linkage, contains IdUA, high sulfate content
  • Keratan sulfate: Gal and GlcNAc, $\beta-1,4$ linkage, lacks uronic acids, variable sulfate content
  • Functions:
  • Chondroitin sulfate: Structural support in cartilage, bones, tendons, and ligaments
  • Keratan sulfate: Structural support in cartilage, cornea, and other connective tissues

  
• What defines the stiffness of a tissue?

  • Stiffness describes a material's resistance to deformation under stress
  • It measures how much the tissue deforms under a given load

  
• What is the formula for stress?

  Stress = Force/Area

  
• What does the term "strain" refer to in material science?

  Strain refers to the fractional length change in a material when subjected to stress.

  
• How is strain expressed mathematically?

  Strain = Change in length/Original length

  
• What aspect of a material describes how much it deforms under a given load?

  Stiffness

  
• What relationship does the stiffness of a tissue have with its deformation under load?

  A higher stiffness indicates less deformation under a given load. Conversely, a lower stiffness means more deformation.

  
• What type of microscopy technique is used in the provided images?

  Scanning electron microscopy (SEM)

  
• What are the key components of connective tissue?

  • Extracellular Matrix (ECM)
  • Cells
• What is the Extracellular Matrix (ECM) in connective tissue?

  A network of macromolecules that maintains cell/tissue integrity
• What is the main function of the ECM in connective tissue?

  It maintains cell and tissue integrity
• What are the main components contained within the Extracellular Matrix (ECM)?

  • Fibrous proteins (e.g. elastin, collagen)
  • Ground substance (amorphous, gelatinous)
• Describe the characteristics of the ground substance in the Extracellular Matrix (ECM).

  Amorphous and gelatinous
• What are Glycosaminoglycans (GAGs) in the Extracellular Matrix (ECM)?

  • Polysaccharides that usually link with proteins to form proteoglycans
• What are the two main roles of the Extracellular Matrix (ECM) in connective tissue?

  • Structural role: provides scaffold and bears mechanical stress
  • Supporting role: transmits chemical signals to regulate cell behavior
• What is the main structural role of the ECM?

  Provides an extracellular ‘scaffold’ structure for the tissue
• What aspect of mechanical stress does the ECM bear in connective tissue?

  The majority of mechanical stress