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DP IB Biology: HL

Topic Questions

Home / IB / Biology: HL / DP / Topic Questions / 2. Molecular Biology / 2.2 Carbohydrates & Lipids / Structured Questions: Paper 2


2.2 Carbohydrates & Lipids

Question 1a

Marks: 1
a)

State the type of bond that forms between two sugar molecules in a disaccharide. 

[1 mark]

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    Question 1b

    Marks: 2
    b)

    Place these types of carbohydrate into decreasing order of molecular size.

    • tetrasaccharides
    • monosaccharides
    • polysaccharides
    • disaccharides

    [2 marks]

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      Question 1c

      Marks: 1
      c)

      A disaccharide has the formula C12H22O11 and is pictured below.

      sucrose

      Draw a ring around the chemical group that bonds two monosaccharides together.

      [1 mark]

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        Key Concepts
        Formation of Sugars

        Question 1d

        Marks: 1
        d)

        Glucose, galactose and fructose all have the same molecular formula but differ in their physical and chemical properties.

        State the collective name for compounds like these, that have the same molecular formula but different properties. 

        [1 mark]

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          Key Concepts
          Formation of Sugars

          Question 2a

          Marks: 2
          a)

          List two properties of starch that make it an effective storage polysaccharide. 

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            Question 2b

            Marks: 2
            b)

            List two properties of cellulose that make it an effective structural polysaccharide. 

            [2 marks]

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              Question 2c

              Marks: 1
              c)

              State the specific type of bond in amylopectin that gives the molecule its highly branched structure. 

              [1 mark]

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                Question 2d

                Marks: 2
                d)

                Glycogen has an even more branched structure than amylopectin, which makes it ideal as an energy storage molecule in animal cells.

                Describe how the branched structure of glycogen helps fulfil its role as a short-term energy storage compound. 

                [2 marks]

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                  Question 3a

                  Marks: 2
                  a)

                  Identify the two distinct parts of a typical fatty acid molecule. 

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                    Key Concepts
                    Fatty Acids: Types

                    Question 3b

                    Marks: 2
                    b)

                    The diagram shows a fatty acid.5Q18GzYb_e-3b

                    i)

                    Identify the type of fatty acid shown in the diagram.

                    [1 mark]

                    ii)

                    State a reason for your answer in part i).

                    [1 mark]

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                      Key Concepts
                      Fatty Acids: Types

                      Question 3c

                      Marks: 2
                      c)

                      The diagram shows a different fatty acid. WAld1UrZ_e-3c

                      Use a tick (✔) in each table to identify words to describe the structure of the fatty acid shown.

                      Monounsaturated Polyunsaturated Saturated
                           

                      All Cis All Trans Mixture of Cis- and Trans-
                           


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                        Key Concepts
                        Fatty Acids: Types

                        Question 3d

                        Marks: 2
                        d)

                        The table below gives information on two different unsaturated fatty acids.

                        Unsaturated Fatty Acid Number of C=C double bonds Melting point / °C
                        A 18 -5
                        B 18 45

                        i)

                        Identify which of these is a cis-fatty acid and which is a trans-fatty acid.

                        [1 mark]

                        ii)

                        State a reason for your answer in part i).

                        [1 mark]

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                          Key Concepts
                          Fatty Acids: Types

                          Question 4a

                          Marks: 1
                          a)

                          The low oxygen content of lipids enables them to be more energy-dense forms of energy storage than carbohydrates. 

                          Explain why.

                          [1 mark]

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                            Key Concepts
                            Long Term Storage

                            Question 4b

                            Marks: 2
                            b)

                            Define the term 'metabolic water'. 

                            [2 marks]

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                              Key Concepts
                              Long Term Storage

                              Question 4c

                              Marks: 1
                              c)

                              The pie chart gives the proportions of the main food groups in the yolk of a typical hen's egg, which serves as a source of nutrition for the growing embryo. This does not include the 'egg white'. e-4c-1

                              Suggest why the lipids sector of the chart is so much larger than that of carbohydrates. 

                              [1 mark]

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                                Key Concepts
                                Long Term Storage

                                Question 4d

                                Marks: 2
                                d)

                                State the type of bond, and the number of those bonds, between fatty acids and a glycerol molecule in a typical triglyceride molecule. 

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                                  Key Concepts
                                  Formation of Lipids

                                  Question 5a

                                  Marks: 3

                                  One mark is awarded for clarity of communication throughout this question

                                  a)

                                  A woman of height 152cm has a body mass of 55 000g.

                                  Using the formula below, calculate the woman's Body Mass Index (BMI)

                                  Body Mass Index

                                  [3 marks]

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                                    Question 5b

                                    Marks: 8
                                    b)

                                    State, with an example in each case, four different ways in which lipids are used in nature. 

                                    [8 marks]

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                                      Key Concepts
                                      Long Term Storage

                                      Question 5c

                                      Marks: 4
                                      c)

                                      Draw a labelled molecular diagram of a triglyceride which contains one monounsaturated fatty acid.

                                      [4 marks]

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                                        Key Concepts
                                        Formation of Lipids