medchem 21 Flashcards
the carbon carrying the R substiuent is called —
alpha carbon
there are – different alpha amino acids in nature and they differ in the —-
- 20
- r group side chain
there are — naturally occurring amino acids which gives rise to —
- 20
- proteins , enzymes , hormones , antibodies
carboxylic acid are acidic when they react with — to give —-
- bases
- carboxylate salt
( as: c.a + Na+ OH- –> carboxylate salt + h20)
amines are — when they react with acids as hydrochloric acid to give —
- basics
- ammonium salt
( R-NH2 + h+ cl- –> ammonium salt )
are amino acids :
- basics
- acidic
- both
both bc of the acid end of the c.a and the amine end
amino acids contains both acidic and basic groups so they undergo —
internal acid base reactions and produce a zwitteron ( aka different charges at the opposite ends )
amino acids exist in a dipolar form ( + and -ve charge in one molecule ) which is called —
zwitteron which means hybrid ions
for an acid in a graph of pH vs. quantity of the base added is called —-
and we use the – to which the pH is read after the addition of the base
- pH titration curve ( check the graph)
- pH meter
-in the pH titration curve we need — equilivent bases to complete the titration and there are – regions of — ( aka the 2 acidic groups ) one w the ph of — and one around —
- the —- of an acidic group is the pH at the point go half neautrilzation of that group
- 2 bases
- 2 regions of neutralisation (check the graph )
- 2.3 of the c.a , 9.7 of the nh3
- the pKa of an acidic group
from point A and B:
from point B and C:
- we neautralized the carboxylic group and we formed a zwitteron amino acid with water
- we nevautrallized the amino group from the zwitteron complex and we add more base to give us neutral amino group and -ve carboxylic group with water
the — point is the point at which the amino acid has an overall charge of zero and doesn’t migrate to cathode or anodr in electric field
- isoelectric point (pl)
for simple amino acid aka one without acidic or basic group the pl is the — of the two pKa
- mean
adult humans can synthesise all 20 amino acids except for – these are called the — amino acids and must be included in the diet
- 9
- essential amino acids
amino acids can be divided into groups dependent on the —
– natural
– acidic
– basic
- R substituents ( non polar ,aliphatic r groups , aromatic r groups , polar , uncharged r groups , +ve changed r groups and -ve charged r groups )
- 15
- 2
-3
the type of r groups:
- non polar , aliphatic which contains H or many ch2
- polar , uncharged contains OH , CH2-SH , or carboys group so C=O with amino group as: CH2-NH2-C=O
- aromatic has a bezne ring
- +ve charged are basic has +ve or histaidne which doesn’t have the +ve charged
- -vely charged which are acidic has the -ve
side chains can be also hydrophobic as:
and they arrange themselves into the centre away from the water phase
side chains can be also hydrophilic which contains — and they arrange themselves into the surrounding water phase
- valine , alanine , phenylaline
- OH groups
( CHECK EXAMPLES SLIDE 17)
cytosine and methionine have — containing groups side chains as:
the two cytosines are often converted into —- within the protein thereby linking them together
- sulphur containing side chain such as thiol ( -SH)
- disulfied
all alpha amino acids are optically active as the alpha carbon has a chiral centre except — -which is an exception
- glycine
( R=H)
all naturally optically active alpha amino acids have – configuration except —-
- S
- Cys bc the COO- have a higher priority than R , ( CHECK EXAMPLE SLIDE 21)
all naturally occurring alpha amino acids including cys ( cystine ) are – in old convention except —
- L
- GLY
B-alanine is a naturally occurring amino acids and its the structural isomer for —-
the neurotransmitter ( GABA ) aka gamma-aminobutryic acid is also a naturally occurring and diffency of it causes huntigtons chorea aka a nearological disorder
- alpha alanine
( CHECK SLIDE 22)
