Unit 4 Amino acids Flashcards
What happens when an amino acid is placed in acidic conditions?
The NH2 group accepts a proton to become NH3+
Why do amino acids have relatively high melting points?
As they exist as zwitter ions there are strong electrostatic forces of attraction between molecules meaning more energy is needed to melt them
What happens when an amino acid is placed in alkaline conditions?
The carboxylic acid group becomes deprotonated to become COO-
What type of bond joins consecutive amino acids within proteins?
Amide bonds - sometimes referred to as peptide links
How are proteins split back into their constituent amino acids?
They are hydrolysed by heating with dilute acid
What is a molecule made up of two amino acids called?
Dipeptide
Do amino acids show optical activity?
All amino acids, except glycine, show optical activity as the central carbon is chiral as there are 4 different groups attached to it
What is the IUPAC name for lycine - NH2CH(COOH)(CH2)4NH2
2,6-diaminohexanoic acid
How can amino acids be separated?
Chromatography
Why do different amino acids have different retention times?
Each amino acid will interact differently with the stationary phase. The stronger the interactions, the higher the retention time
Proteins chains are often arranged in the shape of a helix (spiral). What type of bonding is responsible for this and between which elements do these bonds occur?
Hydrogen bonds form between the H of the N-H and the O of the C=O
