Amino Acids

Question 0

Why can they be described as bifunctional?
How many are there naturally occurring?
Which one cannot exhibit optical isomerism?
What do they all initially exist as?

Answer 0

Have two functional groups, primary amine and carboxylate acid
20
2-aminoethanoic acid
Enantiomers

Question 1

Physical properties
High or low mpt and bpt? Why?
Water soluble?
High or low solubility in non polar solvents?

Answer 1

High bc ionic bonding
Yes
Low

Question 2

Zwitterions
What is a zwitterion?
How does being a zwitterion add to bpt and mpt?
What happens in: Acidic
                             Neutral 
                             Alkaline
solutions?
Does it act as an acid or base?

Answer 2

Species with a positive and negative charge
Attraction between opposite charges
Protonated (+ on N)
Protonated and deprotonated (+ on N - on o)
Deprotonated (- on O)
Both

Question 3

Peptides,Polypeptides,Proteins
What makes a peptide?
What makes a polypeptide?
What makes a protein?

How do you hydrolyse a peptide link?

Answer 3

Two amino acids
Up to 50 amino acids
More than 50

Boil with 6moldm3 hcl for 24 hours or a specific enzyme catalyst. Mixture determined by chromatography.

Question 4

Primary structure
What is it?
How do you identify each amino acid?

Answer 4

Sequence of amino acids

Break down systematically

Question 5

General equation between an amino acid and hydrochloric acid

General equation between an amino acid and sodium hydroxide

Answer 5

RCH(CH2)COOH+HCl>(RCH(NH3)COOH)Cl-

RCH(CH2)COOH+NaOH>(RCH(NH2)COO-)Na+ +H2O

Question 6

Hydrogen Bonding in Proteins
Where do they from?
Draw how this looks
What do they coil to form?

Answer 6

Between O of C=O and H of NH2

Rope like structures