Question
. Which of the following is not a nonpolar amino acid? A . isoleucine B . valine C . methionine D . arginine 2.Which of the following amino acids lacks an asymmetric carbon atom? A . serine B . glycine C . histidine D . glutamine 3 . The type of bond holding the amino acid units together in a dipeptide molecule is called: A. a glycosidic bond B. an ester bond C. a peptide bond D. a protein bond 4 . Peptide bonds , which covalently link two amino acids , result from A. the oxidation of amino acids. B. the condensation of amino acids. C. the hydrolysis of amino acids. D . hydrogen bonds between amino acids.
Answer
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Sebastian
Master · Tutor for 5 years
Answer
1. D. arginine is not a nonpolar amino acid. It is a positively charged (basic) amino acid due to the presence of a guanidinium group in its side chain.2. B. glycine lacks an asymmetric carbon atom. Glycine is the only achiral (lacking chirality) amino acid among the 20 standard amino acids.3. C. a peptide bond holds the amino acid units together in a dipeptide molecule. It forms between the carboxyl group of one amino acid and the amino group of another amino acid, resulting in the release of a water molecule in a condensation reaction.4. B. the condensation of amino acids results in the formation of peptide bonds that covalently link two amino acids to form a dipeptide. This process involves the removal of a water molecule as the amino and carboxyl groups react to form the peptide bond.