Which statement about the amino acid lysine, H2N(CH2)4CH(NH2)COOH\text{H}_2\text{N(CH}_2)_4\text{CH(NH}_2)\text{COOH}H2N(CH2)4CH(NH2)COOH, is correct?
It has no optical isomers because the carbon chain contains repeating −CH2−-\text{CH}_2-−CH2− units.
It reacts with an excess of dilute hydrochloric acid to form a salt containing a cation with a 2+2+2+ charge.
In a strongly acidic solution of pH=1\text{pH} = 1pH=1, it exists primarily as a zwitterion.
It is a monomer that can be polymerised to form polyesters.
30 exam-style questions on AQA A Level Chemistry Amino acids, proteins and DNA (A-level only), covering Amino acids (A-level only), Proteins (A-level only), Enzymes (A-level only), DNA (A-level only), and Action of anticancer drugs (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.