Lesson 3.1.3.1

3.1.3.1 Triglycerides and phospholipids Quiz: AQA Biology, Unit 1

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson 3.1.3.1, Triglycerides and phospholipids: 20 multiple choice questions for the AQA Biology (7402), Unit 1: Biological molecules, written with Revision Ninja.

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The 20 questions

  1. How many fatty acid molecules combine with one glycerol molecule to form a triglyceride?

    • 2
    • 1
    • 4
    • 3

  2. What type of bond is formed between glycerol and a fatty acid?

    • Ester bond
    • Phosphodiester bond
    • Peptide bond
    • Glycosidic bond

  3. How many fatty acid chains does a phospholipid contain?

    • 4
    • 2
    • 1
    • 3

  4. What does the phosphate-containing group in a phospholipid replace?

    • One of the ester bonds linking glycerol to a fatty acid
    • The entire tail region of the molecule
    • One of the three fatty acids of a triglyceride
    • The glycerol backbone of the molecule

  5. What structural feature defines a saturated fatty acid?

    • It contains a phosphate group attached to the end of the chain
    • It has an amino group attached to the carbon next to the carboxyl group
    • It has no carbon-carbon double bonds in its hydrocarbon chain
    • It has at least two carbon-carbon double bonds in its hydrocarbon chain

  6. What effect does a cis double bond have on the shape of a fatty acid chain?

    • It adds an extra ring structure that stops the chain from bending
    • It produces a kink, so the chains cannot pack together as tightly
    • It forms a peptide bond that links the chain to the glycerol
    • It makes the chain straight, so the chains pack together more tightly

  7. Which element is found in the phosphate-containing group of phospholipids but absent from triglycerides?

    • Nitrogen
    • Iron
    • Phosphorus
    • Sulfur

  8. How many water molecules are released when one triglyceride forms from glycerol and three fatty acids?

    • 6
    • 3
    • 1
    • 2

  9. How many ester bonds are present in a phospholipid molecule?

    • 4
    • 2
    • 1
    • 3

  10. A fat that is solid at room temperature is most likely to contain which type of fatty acid?

    • Mainly glycerol, which has a high melting point
    • Mainly phospholipids, which carry a charged phosphate group
    • Mainly saturated fatty acids, which pack tightly together
    • Mainly unsaturated fatty acids with many kinks in their chains

  11. Why does a phospholipid form a bilayer in cell membranes?

    • The fatty acid tails are charged, so they attract water molecules and therefore face outward in the cell
    • The hydrophilic phosphate heads face the water while the hydrophobic fatty acid tails face inward
    • The phosphate heads are hydrophobic, so they face inward away from the water in the cytoplasm
    • The glycerol backbones form covalent links that hold the separate layers of the membrane together tightly

  12. Calculate the molar mass of a triglyceride made from glycerol (92 g/mol) and three stearic acid molecules (284 g/mol each), given that three water molecules (18 each) are removed.

    • 944 g/mol
    • 836 g/mol
    • 890 g/mol
    • 926 g/mol

  13. Which fatty acid is described as unsaturated?

    • A chain containing only single carbon-carbon bonds
    • A chain with an amino group on the first carbon
    • A chain containing one carbon-carbon double bond
    • A chain with a phosphate group on the terminal carbon

  14. Explain why a triglyceride is an effective energy store while carbohydrates are less efficient per gram.

    • Triglycerides are shorter molecules than carbohydrates, so they are broken down more quickly to release energy
    • Triglycerides contain a higher proportion of C-H bonds and less oxygen, so more energy is released per gram on oxidation
    • Triglycerides contain more oxygen atoms than carbohydrates, and these oxygen atoms release energy during respiration in every case
    • Triglycerides dissolve readily in the water of the blood, so they can be transported in large quantities to cells

  15. A student says triglycerides and phospholipids are both lipids that dissolve well in water. Which evaluation is correct?

    • Incorrect, because both are largely nonpolar and insoluble, although phospholipid heads interact with water
    • Correct, because all lipids are water soluble when they contain phosphate
    • Incorrect, because triglycerides dissolve but phospholipids do not contain any polar group
    • Correct, because both are polymers of glycerol that dissolve in water

  16. Explain why a triglyceride forms oil droplets in cytoplasm but a phospholipid forms a bilayer in water.

    • Triglycerides are entirely nonpolar and cluster together, while phospholipids have a polar head and nonpolar tails that form a bilayer
    • Triglycerides contain phosphate and bind readily to water, while phospholipids are entirely hydrophobic in all respects
    • Triglycerides form covalent bonds with the water they meet, while phospholipids form ionic bonds with each other in water
    • Triglycerides are charged and repel each other, while phospholipids are neutral and attract one another strongly in water

  17. Two glycerol molecules each combine with three fatty acids to form two triglycerides. How many water molecules are released?

    • 6
    • 4
    • 12
    • 3

  18. Why does a phosphate-containing head group make the phospholipid region of a membrane more polar?

    • The phosphate group carries negative charge and forms hydrogen bonds with water
    • The phosphate group removes hydrogen ions from water, making the membrane acidic
    • The phosphate group forms covalent bonds with the fatty acid tails, making them soluble
    • The phosphate group is nonpolar and repels water molecules away from the membrane

  19. Which description best explains why saturated fatty acids pack closely in fat storage?

    • Their chains contain amino groups that form hydrogen bonds with water
    • Their chains contain ring structures that interlock with each other
    • Their straight chains have no kinks, so neighbouring chains lie close together
    • Their chains contain phosphate groups that attract one another

  20. A triglyceride stored in adipose tissue is hydrolysed. What products are formed?

    • Glycerol and three fatty acids, with three water molecules used
    • Glycerol and two fatty acids, with one water molecule produced
    • Two glycerol molecules and one fatty acid, with three water molecules produced
    • Glucose and three fatty acids, with three water molecules produced

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