Lesson 3.3.13.1

3.3.13.1 Amino acids Quiz: AQA Chemistry, Unit 3

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson 3.3.13.1, Amino acids: 20 multiple choice questions for the AQA Chemistry (7405), Unit 3: Organic chemistry, written with Revision Ninja.

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The 20 questions

  1. Which two functional groups are present in all naturally occurring 2-amino acids?

    • Amide and ester
    • Amine and carboxyl
    • Alcohol and aldehyde
    • Carbonyl and hydroxyl

  2. What is the overall electrical charge of an amino acid zwitterion?

    • +1
    • +2
    • -1
    • Zero

  3. What type of ion does an amino acid form in a strongly acidic solution?

    • Anion
    • Zwitterion
    • Dicarboxylate
    • Cation

  4. What type of ion is formed by glycine in a strongly alkaline solution?

    • Cation
    • Dication
    • Zwitterion
    • Anion

  5. What is the net charge of an amino acid at its isoelectric point?

    • -1
    • Zero
    • +2
    • +1

  6. Which structure shows the zwitterion of alanine?

    • H2N-CH(CH3)-COOH
    • +H3N-CH(CH3)-COO-
    • H2N-CH(CH3)-COO-Na+
    • H3N+-CH(CH3)-COOH with Cl-

  7. What term describes a substance that can react with both acids and bases?

    • Catalytic
    • Chiral
    • Neutral
    • Amphoteric

  8. What main force between zwitterions gives amino acids unusually high melting points?

    • Van der Waals forces
    • Covalent bonding
    • Ionic attractions
    • Hydrogen bonding

  9. What is the general formula for a standard 2-amino acid?

    • RCH(NH2)COOH
    • RCH(NH2)2
    • RCH2CH2COOH
    • RCO(NH2)COOH

  10. What is the simplest amino acid?

    • Valine
    • Serine
    • Alanine
    • Glycine

  11. Which type of reaction joins two amino acids together to form a dipeptide?

    • Addition
    • Hydrolysis
    • Substitution
    • Condensation

  12. What is the net charge of an amino acid at a pH below its isoelectric point?

    • Negative
    • Zero
    • Positive
    • Neutral

  13. What feature allows the amine group of an amino acid to act as a base?

    • Delocalised pi bond
    • Alpha carbon atom
    • Nitrogen lone pair
    • Carboxyl oxygen

  14. What is the product when glycine reacts with hydrochloric acid?

    • H3N+CH2COOH Cl-
    • H2NCH2COO- Na+
    • H2NCH2COOCH3
    • H3N+CH2COO-

  15. Which organic ion is formed when glycine reacts with aqueous sodium hydroxide?

    • +NH3CH2COOH
    • H2NCH2CH2O-
    • H2NCH2COO-
    • +NH3CH2COO-

  16. Which process forms a zwitterion from an uncharged amino acid molecule?

    • Acid hydrolysis
    • Peptide bond cleavage
    • Internal proton transfer
    • Electron transfer

  17. Which property is shown by all standard amino acids except glycine?

    • Geometrical isomerism
    • Low melting point
    • High volatility
    • Optical isomerism

  18. In a 2-amino acid, which functional group is attached to the alpha carbon atom?

    • Ketone group
    • Amine group
    • Aldehyde group
    • Ester group

  19. What is the net charge of an amino acid at a pH above its isoelectric point?

    • Negative
    • Positive
    • Neutral
    • Zero

  20. Why is glycine the only naturally occurring amino acid that lacks optical activity?

    • No amine group
    • Benzene ring present
    • No carboxyl group
    • Two hydrogen atoms

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