Biomaterials (Lichtenegger) - exam questions 27.05.2015

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nthomas
Beiträge: 4
Registriert: 28.05.2015, 17:44

Biomaterials (Lichtenegger) - exam questions 27.05.2015

Beitrag von nthomas »

Mostly the same questions as Hofi posted in "Biomaterials (Lichtenegger)- exam questions of June 2014":
-) collagene
-) wood
-) cartilage
-) insect cuticle
-) collagene/hair keratin
-) mineralization

additionally she asked for 2 examples in magnetic mineralization.

steffen
Beiträge: 1
Registriert: 26.05.2015, 13:18

Re: Biomaterials (Lichtenegger) - exam questions 27.05.2015

Beitrag von steffen »

Attached you find the exam from 16-06-15.
Du hast keine ausreichende Berechtigung, um die Dateianhänge dieses Beitrags anzusehen.

shevegen
Beiträge: 8
Registriert: 02.02.2012, 13:14

Re: Biomaterials (Lichtenegger) - exam questions 27.05.2015

Beitrag von shevegen »

For 16.05.2015, I wrote them down so that others do not have to manually convert the image into text.

16.05.2015:

1) Structual Levels of Proteins (4 Credit Points, CP):
a) Where (in which part of the cell) does protein synthesis take place?
b) What does the code for different amino acids consist of?
c) How does (bio)synthesis (of proteins) work?

2) Silk (4 CP):
a) What kind of material is silk? (organic/inorganic; polysaccharide/Protein)
b) By which organism is it produced?
c) What is special about its mechanical properties? (2-3 sentences)

3) Mechanical Properties of bone (4 CP):
a) Bone is a mechanically anisotropic material. Its stiffness and strength
depend on the direction of loading and deformation mode, respectively.
Complete the following sentences:
i) Bone is stiffer in ... direction (transverse, longitudinal)
ii) Bone is stronger in ... than in ... than in ... (modes of deformation:
compression, tension, shear)
b) How do the mechanical properties of bone (stiffness, hardness, maximum
strain, toughness) relate to the mineral content?

4) Wood cell wall (4 CP):
a) Which are the 3 main components of the wood cell wall? How are they
arranged into a composite material?
b) What is the "microfibril angle", and what is its mechanical function?

5) Diagram reading exercise (4 CP):
a) The below diagram shows typical stress-chain curves of alpha-keratin
(e. g. wool, hair)
-> Explain the shape of the curve qualitatively. What happens to the
structure of keratin on the molecular level?
-> One curve was recorded at lower, one at higher degree of hydration.
Which one is which? Mark the curves accordingly in the diagram.
b) Find the correct name for the amino acids below and mark the
corresponding check box! In which proteins do these amino acids
occur!

6) Nacre or "Mother of Pearl" (4 CP)
Nacre (Mother of Pearl) is a biomineralized material grown by sea
shells.
a) Why is the mineral in nacre aragonite and not calcite (which
would be the most stable crystalline polymorph of calcium
carbonate)? Explain!
b) Nacre is harder and in particular much tougher than pure
calcium carbonate (CaCO3). Name and shortly describe 3
toughening strategies found in nacre!

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