Qualification > Sciences
Edexcel BIOLOGY Doubts!!!!
hissyfit:
I will ask on The Student Room and see if I get any answers,will post here if I do
hissyfit:
you can see the replies here : http://www.thestudentroom.co.uk/showthread.php?t=1535284&stat_userid=413917&stat_usergroupid=12&stat_membergroupids=&stat_widgettype=secondary&stat_widgetname=widget_watched_threads
:)
guMnam:
hmm....Thanks for ur help :D
hissyfit:
Plant Fibres-why do some stretch more than others?
Any ideas,googling didn t help
Has it got to do with their structure or their composition( materials they are made up of)?
Thanks
+rep
I was given these hints: Think about the molecular structures involved. Proteins and polysaccharides form secondary structures - what are they? What types of forces are involved in them? What about tertiary structures?
My attempts - I have no idea other than the glycosidic bonds in cellulose.I don t know what secondary structures polysaccharides form other than long chains.
I know there are hydrogen bonds in secondary strucure in proteins+varipous bonds in tertiary structure .
I m really stuck plz help!
Deadly_king:
--- Quote from: hissyfit on February 07, 2011, 02:20:16 pm ---Plant Fibres-why do some stretch more than others?
Any ideas,googling didn t help
Has it got to do with their structure or their composition( materials they are made up of)?
Thanks
+rep
I was given these hints: Think about the molecular structures involved. Proteins and polysaccharides form secondary structures - what are they? What types of forces are involved in them? What about tertiary structures?
My attempts - I have no idea other than the glycosidic bonds in cellulose.I don t know what secondary structures polysaccharides form other than long chains.
I know there are hydrogen bonds in secondary strucure in proteins+varipous bonds in tertiary structure .
I m really stuck plz help!
--- End quote ---
That's for sure.........the molecular structure has a lot to do with this stretching thing about fibers. ;)
Let's get to the root of it........definition of fibers.
--- Quote from: http://waynesword.palomar.edu/traug99.htm ---Fibers are elongate cells with tapering ends and very thick, heavily lignified cell walls. Fiber cells are dead at maturity and function as support tissue in plant stems and roots. The lumen or cavity inside mature, dead fiber cells is very small when viewed in cross section.
--- End quote ---
So my first conclusion........lignin certainly has something to with it. i think that the more lignin the fiber possess, the less will it stretch. ;)
Now you should look back at your notes on cell membrane. What is the name of the thing that is responsible for elasticity?
This should certainly give you a hint. :D
Another point : Plant cell walls are composed essentially of two polymer constituents, a network of highly structured microfibrils embedded in a relatively unstructured matrix.
So now you need to make some research on the components of cellulose as well and how it forms elastic microfibrils. ;)
Hope it helps. :)
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