PL 1 Flashcards
What groups do amino acids contain?
- Carboxylic acid
- Amine
What is an amine group?
NH2
What are proteins made from?
Amino acid monomers made through a condensation reaction
What happens when two amino acids join?
A dipeptide is formed and water is removed
What does a peptide link look like?
A carbon with a double bond oxygen
Attached to
A nitrogen with a hydrogen
What happens when proteins are hydrolysed using acids?
Amino acids are formed
However the amine group accepts a proton to become NH3+
What is the primary structure of protein?
A single polypeptide chain of amino acids
What is the secondary structure of protein?
A helix or pleated sheet held together by hydrogen bonds
What is the tertiary structure of protein?
The polypeptide chain folds into a 3D shape with hydrogen and disulfide bonding
How are proteins stabilised?
Disulfide bridge forms and two hydrogen atoms are lost
What does amphoteric mean and why are amino acids amphoteric?
They can react with both acids and bases
- nitrogen accepts a proton due to lone pair
- carboxylic acid donates a proton
How is a zwitterion formed in aqueous solutions?
The hydrogen from the carboxylic acid group forms a bind with the amine group
- carboxylic acid group has negative charge
- amine group gains positive charge
What is an isoelectric point?
The pH value at which the amino acid exists as a zwitterion
What is a base?
A proton acceptor
What is an enantiomer?
A non superimposable mirror image
