Extracellular Matrix & Cell Adhesion

Question 1

What body parts made up of type I collagen

Answer 1

tendons
Organs
Skin
Bones
Connective tissue
Teeth

Question 2

What body parts made up of type II collagen

Answer 2

Cartilage

Question 3

What body parts made up of type III collagen

Answer 3

Muscles
Arteries
Reticular fibres

Collagen III- found mainly in reticular fibres ( fine fibrous connective tissue occurring in networks to make up the supporting tissue of many organs).

Question 4

What is made up of type IV collagen

Answer 4

The basal lamina (a network of the extra cellular matrix)

Question 5

What body parts made up of type V collagen

Answer 5

Bone matrix
Cornea

Question 6

What is the macromolecular network of the ECM composed of

Answer 6

Collagens
Elastin
Glycoproteins
Proteoglycans

Question 7

What do the ECM macromolecules form in which cells thrive

Answer 7

Macromolecules of ECM form a 3D gelatinous bed in which cells thrive

Question 8

What are the 2 types of collagen

Answer 8

Fibrillar (fibril forming)
Non-fibrillary

Question 9

Give 2 examples of Fibrillar collagens

Answer 9

Type I & type II collagen

Question 10

What is a Fibrillar collagen, where is it found and what doe they provide

Answer 10

A Fibrillar collagen is a fibril forming collagen
They are major component in tendons, ligaments, skin
They provide HIGH TENSILE STRENGTH

Question 11

Give 2 examples of non-Fibrillary collagens

Answer 11

Type IV & type VI

Question 12

What is a non-fibrillary collagen, where is it found and what doe they provide

Answer 12

A non-fibrillary collagen is one that doesn’t form fibrils
They form MICROFIBRILS or mesh like structures
They are structural component of basement membranes
They provide anchorage for cells and filtration

Question 13

Describe the structure of collagen and why it is strong

Answer 13

Triple helical structure formed by 3 peptide chains
- every 3rd amino acid is glycine. Glycine is the smallest amino acid which means it allows alpha helices to wrap around as they’re so small. These form tight fibril
- Gly-X-Y (proline-hydroxyproline

Question 14

What is osteogenesis imperfecta and it’s cause

Answer 14

Brittle bone disorder, congenital
Caused by genetic defects in collagen I synthesis

Question 15

What is osteogenesis imperfecta characterised by

Answer 15

Fragile bones
Thin skin
Thin sclera of eye (whites of eye look blue almost)
Abnormal teeth
Weak tendons

cause:
80%–90% of Osteogenesisimperfecta cases are caused by autosomal dominant mutations in the type 1 collagen genes, COL1A1 and COL1A2. Mutations in one or the other of these genes cause the body to make either abnormally formed collagen or too little collagen.

Question 16

Describe the specific single base change mutation (substitution) in osteogenesis imperfecta

Answer 16

Single base change mutations converts glycine to a bulky amino acid instead
This prevents the correct folding of collagen chains to form fibrils

Question 17

What is the more severe type of osteogenesis imperfecta and why do babies usually not survive

Answer 17

Type II osteogenesis imperfecta, dominant if affected individuals survive
Babies usually die at birth as born with too many broken bones

Question 18

What is elastin found in?

Answer 18

Blood vessels 🩸
Ligaments
Lungs 🫁
Skin
Tendons

Question 19

Both elastin and collagen are rich in what 2 amino acids

Answer 19

Glycine and proline

Question 20

What amino acid does elastin have more of and why does this give it elasticity

Answer 20

Elastin has more VALINE (than collagen) which interacts with hydrophobic domains giving it elasticity

Question 21

Elastin fibres are usually covered by which glycoprotein + why is it important

Answer 21

Elastin fibres usually covered by glycoprotein FIBRILLIN — this coats elastic fibres & restricts the stretch of elastin as we don’t want too much stretch

Question 22

What is Marfan syndrome causes by

Answer 22

Marfan syndrome is a rare connective tissue disorder (1 in 10k)
Mutations in FIBRILLIN gene — if fibrillin is absent or midfielded this leads to changes in ECM properties

Question 23

Marfan syndrome characteristics

Answer 23

•tall stature/ long arms/legs
•arachnodactyly (spider fingers)
•loose joints
•floppy cardiac valves
•eye problems (lens dislocation)
•aortic aneurysms

Question 24

In Marfan syndrome, which growth factor is not bound with extracellular matrix (ECM)

Answer 24

TGF- beta is not bound to ECM : accumulates in lungs and heart instead which changes ECM of organs where there’s a lot of elastic fibres

Question 25

Why must we regulate growth factors

Answer 25

They can lead to CANCER