Lesson 1.4.3

1.4.3 Triglycerides, saturated and unsaturated lipids Quiz: Pearson Edexcel Biology A (Salters-Nuffield), Unit 1

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson 1.4.3, Triglycerides, saturated and unsaturated lipids: 20 multiple choice questions for the Pearson Edexcel Biology A (Salters-Nuffield) (9BI0), Unit 1: Lifestyle, Health and Risk, written with Revision Ninja.

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The 20 questions

  1. What type of bond links glycerol to each fatty acid in a triglyceride?

    • Peptide bond
    • Glycosidic bond
    • Hydrogen bond
    • Ester bond

  2. How many fatty acids are joined to one glycerol molecule in a triglyceride?

    • 4
    • 2
    • 1
    • 3

  3. How many water molecules are removed when one triglyceride is formed from one glycerol and three fatty acids?

    • 1
    • 6
    • 2
    • 3

  4. Which of these is the correct description of a saturated fatty acid?

    • It has no carbon-carbon double bonds in its hydrocarbon chain
    • It has one or more carbon-carbon double bonds in its hydrocarbon chain
    • It contains a glycosidic bond between two glycerol molecules
    • It contains a peptide bond between two amino acid units

  5. Why are saturated fats usually solid at room temperature?

    • They contain more water than unsaturated fats, which makes them solid at room temperature
    • Their kinked chains prevent packing, so they are more fluid than unsaturated fats
    • They contain glycosidic bonds, which harden the fat when it cools to room temperature
    • Their straight chains pack together closely, so intermolecular forces are stronger

  6. Why do unsaturated fatty acids have lower melting points than saturated fatty acids of similar length?

    • The double bonds form glycosidic links between chains, which makes the fat more rigid
    • The double bonds add extra hydrogen atoms to the chain, which increases the attraction between molecules
    • The double bonds make the chains more compact, so they pack together more tightly than saturated chains
    • The carbon-carbon double bonds introduce kinks, so the chains cannot pack closely together

  7. Which statement about triglycerides as energy stores is correct?

    • They store the same energy per gram as glycogen, because both are made of glucose units
    • They store less energy per gram than carbohydrates, because they contain more oxygen
    • They store energy only in the glycerol part, so the fatty acids contribute nothing to energy
    • They store more energy per gram than carbohydrates, because they are more reduced and less hydrated

  8. What products are formed by the hydrolysis of a triglyceride?

    • Glucose and fructose
    • Amino acids and water
    • Three glycerol molecules and one fatty acid
    • Glycerol and three fatty acids

  9. Which enzyme hydrolyses triglycerides during digestion?

    • Maltase
    • Amylase
    • Protease
    • Lipase

  10. A triglyceride is made of glycerol, C3H8O3, and three identical saturated fatty acids. Which statement about its formation is correct?

    • Three water molecules are added in the condensation reactions that form the three ester bonds
    • Three glycosidic bonds are formed between the glycerol and the fatty acids in the reaction
    • Three water molecules are removed in the condensation reactions that form the three ester bonds
    • Two water molecules are removed, because only two of the hydroxyl groups react in the reaction

  11. Which of these is a source of unsaturated fat in the diet?

    • Butter, which is solid at room temperature and mostly saturated
    • Lard, which contains a high proportion of saturated fatty acids
    • Olive oil, which is liquid at room temperature
    • Coconut oil, which is mostly saturated and solid at room temperature

  12. Hydrogenation of an unsaturated vegetable oil converts some C=C bonds into C-C bonds. What is the effect on the fat?

    • It becomes an amino acid and its melting point is unchanged
    • It becomes a carbohydrate and its energy content falls sharply
    • It becomes more saturated and its melting point rises
    • It becomes more unsaturated and its melting point falls

  13. Which statement about the energy released by 1 g of triglyceride compared with 1 g of glycogen is correct?

    • Triglyceride releases the same energy per gram because both are fuels for respiration
    • Glycogen releases much more energy per gram than triglyceride because it is insoluble
    • Triglyceride releases more than twice as much energy per gram
    • Triglyceride releases less energy per gram, because it contains water

  14. Why is a low saturated fat intake advised for reducing cardiovascular disease risk?

    • Saturated fats lower HDL levels, which increases the clearance of cholesterol from arteries
    • Saturated fats increase the concentration of glucose in the blood, which damages arteries
    • Saturated fats contain glycosidic bonds, which the body cannot hydrolyse safely
    • Saturated fats raise LDL cholesterol levels, which contribute to plaque formation

  15. Which of these is an example of a monounsaturated fatty acid?

    • Linoleic acid, with two C=C double bonds in its chain
    • Palmitic acid, with no C=C double bonds in its chain
    • Oleic acid, with one C=C double bond in its chain
    • Glycerol, which has three hydroxyl groups and no carbon chain

  16. Which feature of a triglyceride makes it insoluble in water?

    • Its glycosidic bonds are broken by water, which then stops it dissolving
    • Its glycerol part forms many hydrogen bonds with water, which makes it very soluble
    • Its long non-polar hydrocarbon chains dominate, so it does not form hydrogen bonds with water
    • Its amino acid units carry charges, which repel the water molecules around it

  17. Which of these best describes the difference between a saturated and an unsaturated triglyceride?

    • Saturated triglycerides contain amino acids joined by peptide bonds
    • Unsaturated triglycerides contain glycerol units joined by glycosidic bonds
    • Saturated triglycerides contain fatty acids with one or more C=C double bonds
    • Unsaturated triglycerides contain fatty acids with one or more C=C double bonds

  18. A student compares the energy released by equal masses of a triglyceride and a carbohydrate. Which factor is most responsible for the difference in energy content?

    • Triglycerides contain more glycosidic bonds, which are a major source of energy in respiration
    • Carbohydrates contain more nitrogen, which is oxidised to release energy in respiration
    • Triglycerides contain a higher proportion of C-H bonds, which release more energy when oxidised
    • Carbohydrates contain more water, which increases their energy release during respiration

  19. What is the role of the glycerol component in a triglyceride?

    • It provides the hydrophilic head that binds to water in the cell membrane
    • It acts as a glycosidic linkage between fatty acids, forming a polysaccharide chain
    • It is the amino acid unit that forms peptide bonds with fatty acids in the triglyceride
    • It provides a three-carbon backbone to which three fatty acids are attached by ester bonds

  20. Which of these explains why the formation of a triglyceride is described as a condensation reaction?

    • Two glycerols combine and release a fatty acid as a by-product of the reaction
    • Water is added as each ester bond forms, which breaks the glycerol backbone
    • Oxygen is removed from each fatty acid as an ester bond forms
    • Water is removed as each ester bond forms between glycerol and a fatty acid

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