Amino acids, peptide bond, protein structure, denaturation
- Which of the following is a basic amino acid ? Answer: 4. Lysine A basic amino acid has an extra basic group (amino) in its side chain. Lysine, H₂N(CH₂)₄CH(NH₂)COOH , has two amino groups... 1
- Which of the following is a natural polymer ? Answer: 1. cis-1,4-polyisoprene Natural rubber is cis-1,4-polyisoprene, a polymer made by plants. Poly(butadiene-styrene) (SBR), polybutadie... 1
- The non-essential amino acid among the following is : Answer: 3. alanine Essential amino acids cannot be made by the body and must come from food: valine, leucine, lysine (and isoleucine, etc.).... 1
- Which of the following compounds can form a zwitterion ? Answer: 4. Glycine A zwitterion needs both an acidic group and a basic group in the same molecule, so the proton moves from the acid to the... 1
- Regarding cross-linked or network polymers, which of the following statements is incorrect ? Answer: 4. They contain strong covalent bonds in their polymer chains. Cross-linked (network) polymers are formed from bi- and tri-functiona... 1
- Which of the following are not polymeric ? Answer: 3. Lipids Key idea: A polymer is a long chain of repeating monomer units. Proteins: chains of amino acids. Polysaccharides: chains o... 1
- Which of the following statements is not correct ? Answer: 3. Denaturation makes the proteins more active. Key idea: denaturation destroys the 3-D structure. On denaturation (heat, acid), sec... 1
- In a protein molecule various amino acids are linked together by : Answer: 3. peptide bond Key idea: amino acids join through the amide linkage between the -COOH of one and the -NH₂ of the next, formed by lo... 1