19A.5 Flashcards
what are amino acid
they are compounds with both a amino group and a carboxylic group but are separated by a carbon
what are the known amino acids and there sructures
alanine - the carbon is attached to a methyl group
cysteine - the carbon is attached to a CH2 which is attached to SH
Glutamic acid - the carbon is attached to propanoic acid
glycine - carbon is only attached to h making it the simplest one
lysine - the carbon is attached to butlyamine
what are amino acids often called and why
2 amino acids since the NH2 group is attached to the second carbon counting from the COOH
proteins are made from
amino acids
how do we name amino acids by there UPAC name
They are amine derivatives of carboxylic acid, with the prefix of amino to indicate the amino group and the locant for which carbon atom its attached to and then the rest is following the normal structure
amino acids are not
naturally occurring
what does the structural formula, displayed formula, skeletal formula of amino acids look like
page 250
what does isoelectric points mean
The PH of an aq solution (of amino acids) in which it is neutral i.e the PH of a aq zwitter amino acid
what is the solubility of amino acids
they are all soluble in water
amino acids can act as both
acid and base as they have the acid-base character
what is the chemical reaction when amino acids react with water leaving an alkaline solution
N2H - R - COOH + H20 —> N3H^+1- R - COOH + OH^-
what is the chemical reaction for when amino acids react with water leaving an alkaline solution
N2H - R - COOH + H2O —-> N2H - R -COOH^- + H3O^+
what is the chemical reaction for when an amino acids functional groups (react)
it is a H+ transfer
reaction:
H2N - R - COOH ⇌ H3N^+ - R - COO^- (this is a zwitterion)
What is a zwitterion
a molecule containing a positive and a negative charges but has no overall charge
what does the number of isoelectric point tell us about the amino acids properties
if the isoelectric point is low it indicates that the amino acid is predominantly acidic, and is the isoelectric point is high then the amino acid is predominantly a base
the isoelectric point is linked with the amino groups and acid groups in what way?
if there is more amino groups in the molecules then the isoelectric point is higher, and if there is more carboxylic groups in the molecules then the isoelectric point is lower
why are proteins used involved in buffering solutions
because they contain an amino acid which has both an acid and base character following there two groups of NH2 and COOH (also we need a isoelectric point in the middle yk)
all amino acids can form salts with
acids and bases
what is the structure of the salt when alanine reacts with acid
the protonated structure is page 251
how many salts can glutamic acid form and why
it can form 3 salts since they have 2 COOH groups so either one can react or both
what is the structure and use of monosodium glutamate and how is it made
structure page 251
use - flavour enhancer in food
made - reaction of glutamic acid with a base where the main COOH only reacts
most 2-amino acids contain
a chiral center, so they are optically active, the excepion is glycine
aq enantiomers of amino acids do what
rotate the plane of polarization of plane polarized light. some are dextrorotatory (clockwise) and some are laevorotatory (anti clockwise)
if an amino acid is synthesised in a laboratory then
a racemic mixture is formed