polymers and life Flashcards
define amphoteric
when a compound exhibits both acidic and basic properties
what is a zwitterion?
an overall neutral molecule that has both a positive and negative charge in different places on the molecule
what is the isoelectric point?
the pH at which the charge on the amino acid is 0
What is an enantiomer?
mirror images/non superimposable
What is the difference between normal light and plane polarised light?
Normal light vibrates in all directions, whereas plane polarised light vibrates in one direction
How do optical isomers affect plane polarised light?
One enantiomer rotates light in a clockwise direction, the other rotates it in an anti-clockwise direction
Describe a test for an amine
Add small amount of acyl chloride -> white fumes of HCl = amine
Which functional group do amides contain?
-CONH2
Why do amides behave differently to amines?
The presence of carbonyl group pulls electrons away from the rest of the group
Which type of amide hydrolysis results in a carboxylic acid and ammonium salt?
Acid hydrolysis
What type of amide hydrolysis gives a carboxylate ion and ammonia?
Basic hydrolysis
How are nylons made?
In a condensation reaction between a diamine and a dicarboxylic acid
What do x and y represent in nylon-x,y?
X= number of carbons in diamine Y= number of carbons in dicarboxylic acid
what monomers are polyamides made from?
dicarboxylic acid and diamine
what monomers are esters made from?
dicarboxylic acid and diamine
why does the M+1 peak exist?
small proportion of organic molecules in a sample will contain 13 C carbon
what is a test for carboxylic acid?
carbonates
what is the difference between a primary and secondary amide?
primary amide directly bonded to one carbon whereas a secondary amide has N bonded to more than one carbon
what are DNA and RNA examples of?
condensation polymers joined from nucleotides
how does the phosphate-sugar backbone in DNA form?
phosphate joins by condensation with deoxyribose
how do the bases in DNA join to the phosphate-sugar backbone?
condensation with the deoxyribose
explain how helices and sheets are held together in secondary protein structure
hydrogen bonds between NH groups on one peptide link and c=o groups on another
how does the ethanedioate ion behave as a ligand?
- bidentate ligand
- uses two lone pairs to form co-ordinate bonds to a central metal
name a bidentate ligand (not ethanedioate or water)
-1,2-diaminoethane
how does a ligand bond to a metal ion in a complex?
level 3 orbitals are organised so that there are 6 new orbitals with equal energy
why does water form six co-ordinate bonds when it behaves as a ligand?
by making the maximum amount of bonds, it is most energetically stable
what type of ligand is EDTA?
hexadentate
how do you calculate rate from a curved graph?
draw tangent from steepest point
how do you calculate the concentration of the salt in a buffer?
Ka x weak acid/ H+
