Amino Acids Flashcards
What is meant by the term ISOELECTRIC POINT?
The pH value at which the amino acid exists as a Zwitterion
What is meant by the term Zwitterion?
A dipolar form of an AMINO ACID, that is formed by the DONATION of a H+ ion from a CARBOXYL group ▶️ AMINE GROUP
COOH ▶️ COO- ➕ H+
Explain what happens to a Zwitterion when the Isoelectric Point decreases (lower pH).
The amino acid/zwitterion ACTS AS A BASE
(Forms a ➕ion)
By accepting a H+ from the acid
It becomes a positive ion in an acidic solution.
Explain what happens to a Zwitterion when the Isoelectric Point increase (higher pH).
The amino acid/zwitterion ACTS AS AN ACID.
By donating H+ to the base it is surrounded in
It becomes a ➖ ion in an alkaline solution.
E.g. At pH13, the H+ from the NH3+ amine group donates a proton (becomes NH2) to the base (OH- + H+ ▶️ H2O)
NH2-CHR-COO➖
State the conditions for the ACID HYDROLYSIS of an Amino acid (with dipeptide bonds).
- Aqueous Acid
- Heated under REFLUX
- With 6mol/dm-3 HCl for 24hrs
- The amino acid(s) formed are positively charged due to the presence of H+ ions from the acid
- Carboxyl groups are reformed and Amine stay at NH3+
State the conditions required for the ALKALINE HYDROLYSIS of an amino acid (with dipeptide bonds)
- Aqueous Sodium Hydroxide (NaOH)
- Just under 100*C
- Forms Sodium Salts (COO-Na+)
- Amine group reformed from OH (of NaOH)
Explain what is meant by the term Condensation reaction.
Where 2 small molecules react together to form a larger molecule with the elimination of a small molecule e.g. H2O
This question is about the reaction between Amines and Carboxylic Acids.
What is the product of:
Methyl amine ➕ Ethanoic Acid?
CH3NH2. ➕ CH3COOH
This is a condensation reaction in which H2O is released.
The product of Methylamine + Ethanoic Acid is
N-Methyl ethanamide
(The methyl group is on the N)
CH3NHCOCH3
This question is about the reaction between Amines and Carboxylic Acids.
How would you create Methylamine and Ethanoic Acid from N-Methyl ethanamide?
N-Methyl ethanamide ➕ H2O ▶️ Methylamine + Ethanoic Acid
Proteins can also be converted into amino acids in the laboratory.
State the reagents and condition required and stater the type of reaction taking place. [3]
6mol fm-3 HCL
Heated Under Reflux
And
Hydrolysis
Explain what an A(alpha) Amino Acid is?
General Formula:
RCH(NH2)COOH
H2N-CHR-COOH
