(YELLOW) amino acids , polymers and protiens Flashcards
what does a acid do with hydrogens
it donates them
what does a base do with hydrogens
it accepts them
what does amphoteric mean
it means it acts both as a base and a acid
how do you tell if somthing is polar or non-polar
Non polar molecules are symmetric with no unshared electrons. Polar molecules are asymmetric, either containing lone pairs of electrons on a central atom or having atoms with different electronegativities bonded.
how do you know if somthing is hydrophobic
if it is non-polar
info card read and recite
made by me so its gonna be waffle
also draw how a zwitterion is formed
a zwitter ion forms when an amino acid is at its normal state e.g when it is in pH 7 , this is NH3(+)CHRCOO(-) and this is when the amino acid is at its isoelectric point
this is acheived by The -COOH of one molecule will protonate the -NH2 group of an adjacent molecule forming a zwitterion.
this is further proven as zwitter ions show charactisitics of ions :
1) they are white solids which melt or decompose at relativly high tempreatures around 300 oC
2) they are soluable in water
in acidic conditions this amino acid is formed
NH3(+)CHRCOOH
is basic conditions this amino acid is formed :
NH2CHRCOO(-)
what is a isoelectric point and how is it effected
an isoelectric point is a point at which a zwitter ion is formed , this is effected by the R group on the amino acid.
At what pH can an amino acid act as a nucleophile? Explain
A nucleophile has a lone pair on the N. This only occurs at higher pH values
At what pH can an amino acid act as an acid? Explain
at the isoelectric point the -NH3+ group can donate a proton; at lower pH values the -COOH group can also donate a proton
how can amino acids act as buffers
acts as a buffer removing added H+ or OH- so minimising the change in pH.
what is the reaction called when two peptides join what does it produce
amide link
H2)
how would you heat a dipeptdie to give a zwittwer ion
give conditions and reagents
conditions heat under reflux
reagents : 6M HCl followed by addition of water
1) dipeptide splits when adding 1 water and 2 H+
this is done in acidic conditions this gives you
2 x NH3CHRCOOH
2) add more water to remove the pH imbalance to give you
2x NH2CHRCOOH + 2H3O(+)
these amino acids can now be examined
info card read and recite
POLYESTERS
Polyesters are formed from the reaction between a dicarboxylic acid and a diol or a diacyl chloride and a diol or even a molecule which has an alcohol group on one side and a carboxylic acid/acid chloride group on the other.
an polyester can form between a acy chloride and hydroxide group
Do you consider that there might be disposal problems with this nylon? Why?
Proteases (enzymes) can hydrolyse peptide bonds but not between long hydrocarbon chains. Nylon is hydrolysed by strong acids/alkalis at high temps.
Suggest how the strength of the nylon polymer may be increased
extrusion and cold drawing results in polymer chains being aligned (more crystalline regions) in which adjacent chains can form H- bonds with one another. Lone pair on C=O: bonds with d+H –N forming H-bond.
