Lecture 11 Flashcards
1
Q
fibroblast
A
sit in spaces of connective tissue. bundle of collagen. organized
2
Q
extracellular matrix
A
• Gel-like “ground substance” • Primarily made up of polysaccharides -Glycosaminoglycans (GAGS) -proteoglycans • Fibrous proteins -Collagen, elastin, fibronectin, laminin -Structure and adhesive functions
3
Q
proteoglycan
A
protein that has sugars
4
Q
lamin
A
intermediate filaments on inner part of nucleus, where chromosomes gets bound to
5
Q
laminin
A
extracellular matrix protein
6
Q
GAGS
A
- Repeating disaccharide units
- One is an amino sugar
- Charged - sulfate and carboxyl groups
- Most anionic molecules of animal cells(negative)
7
Q
what follows charge?
A
water
8
Q
since GAGS are the most anionic molecules
A
- Attract positive ions (Na+)
- Attracts H2O
- Hydration creates swelling pressure - called turgor
- Protects joints - cartilage matrix protects from compressive forces
9
Q
GAGS examples
A
• Hyaluron - not sulfated -secreted directly from cell surface -doesn’t have to be bound to a protein • Dermatin or chondroitin sulfate • Heparin sulfate • Keratin sulfate
10
Q
what is the function of GAGS?
A
regulate activity of secreted proteins
- Immobilize secreted molecules close to where they are secreted
- Provide a reservoir of protein for later use
- Protects proteins from proteolytic degradation
11
Q
Inflammatory response
A
chemokines are immobilized by proteoglycans on endothelial cells and allows for homing of lymphocyte
12
Q
fibrous proteins of ECM
A
-Collagen
-Elastin
-Fibronectin
they’re covalently bound to one another.
13
Q
Collagen
A
- Limits stretching and prevents tearing
- Skin and bone
- Secreted by fibroblasts
- 3 alpha helices: GXY; modified aa (hydroxyproline and hydroxylysine)
- intramolecular linkages
14
Q
GXY
A
(glycine [smallest], x and y are modified amino acids).
15
Q
hydroxyproline and hydroxylysine are
A
imino acids
