AQA · A-Level · Biology

    Course version: 7402 · Version from Sept 2016

    Monosaccharides are the monomers from which larger carbohydrates are made.…

    Full specification wording

    Carbohydrates: Monosaccharides are the monomers from which larger carbohydrates are made. Glucose, galactose and fructose are common monosaccharides.

    Monosaccharides are single sugar units that act as the monomers from which larger carbohydrates are made.

    Checked against the AQA 7402 specification (opens in a new tab) on .

    • Point 1 of 8
    • 3 key terms

    Study notes

    From the checked teaching notes for this specification point.

    The idea

    Monosaccharides are single sugar units that act as the monomers from which larger carbohydrates are made. Glucose, galactose and fructose are the common monosaccharides named in this specification. Monosaccharides can join in condensation reactions to form disaccharides and polysaccharides, while hydrolysis separates larger carbohydrates into smaller sugar units. This monomer relationship is the key distinction: a monosaccharide is one building block, whereas a larger carbohydrate contains sugar units joined by bonds.

    What earns the marks

    • State that monosaccharides are the monomers from which larger carbohydrates are made, bonding via condensation reactions to form disaccharides and polysaccharides.
    • Name glucose, galactose and fructose as common monosaccharides.
    • Explain that a monosaccharide is one sugar unit and is therefore a monomer rather than a carbohydrate polymer.
    • Link monosaccharides to the formation of larger carbohydrates through condensation reactions.

    Common mistakes and how to put them right

    • Confusing monosaccharides with disaccharides.

      Put it right: Sucrose, maltose and lactose are disaccharides, whereas glucose, galactose and fructose are monosaccharides.

    • Stating that monosaccharides are polymers.

      Put it right: Monosaccharides are the individual monomers that bond together to form larger carbohydrates.

    • Giving examples of disaccharides when asked for common monosaccharides.

      Put it right: Use glucose, galactose and fructose.

    Exam tips

    • When asked to define a monosaccharide, explicitly use the term 'monomer' and state they form larger carbohydrates.
    • If asked for examples, give the three named in the specification: glucose, galactose and fructose.

    Try the lesson

    The start of the Carbohydrates: Monosaccharides are the monomers from which larger carbohydrates are made. Glucose, galactose and fructose are common monosaccharides. lesson, made from checked teaching notes for this specification point.

    Have a go first

    Which of the following is a common monosaccharide?

    Listen

    Monosaccharides are single sugar units that act as the monomers from which larger carbohydrates are made. Glucose, galactose and fructose are the common monosaccharides named in this specification. Monosaccharides can join in condensation reactions to form disaccharides and polysaccharides, while hydrolysis separates larger carbohydrates into smaller sugar units. This monomer relationship is the key distinction: a monosaccharide is one building block, whereas a larger carbohydrate contains sugar units joined by bonds. A strong answer earns marks for these points. State that monosaccharides are the monomers from which larger carbohydrates are made, bonding via condensation reactions to form disaccharides and polysaccharides. Name glucose, galactose and fructose as common monosaccharides. Explain that a monosaccharide is one sugar unit and is therefore a monomer rather than a carbohydrate polymer. Link monosaccharides to the formation of larger carbohydrates through condensation reactions. A common slip: Confusing monosaccharides with disaccharides. Instead, sucrose, maltose and lactose are disaccharides, whereas glucose, galactose and fructose are monosaccharides. Exam tip: When asked to define a monosaccharide, explicitly use the term 'monomer' and state they form larger carbohydrates.

    See it

    A top-down flowchart. At the top is a node labelled Monosaccharides. Two arrows lead from it. The first arrow goes to a node labelled Monomers from which larger carbohydrates are made, which leads to a node labelled Join by condensation reactions, which in turn branches to two nodes: Disaccharides and Polysaccharides. The second arrow from Monosaccharides goes to a node labelled Common monosaccharides, which branches to three nodes: Glucose, Galactose and Fructose.
    It shows monosaccharides as the monomers that join by condensation reactions to form disaccharides and polysaccharides, and names glucose, galactose and fructose as common monosaccharides.

    Key words

    Say what each word means before you turn the card.

    monosaccharides

    Try answering aloud or in your head before turning the card.

    glucose

    Try answering aloud or in your head before turning the card.

    fructose

    Try answering aloud or in your head before turning the card.

    See every definition
    monosaccharides
    The monomers from which larger carbohydrates are made; glucose, galactose and fructose are common examples.
    glucose
    One of the common monosaccharides named in the specification.
    fructose
    One of the common monosaccharides named in the specification.

    Label the diagram

    Some boxes have lost their names. Pick the right name for each number.

    The diagram again, with 3 boxes numbered instead of named. A top-down flowchart. At the top is a node labelled Monosaccharides. Two arrows lead from it. The first arrow goes to a node labelled Monomers from which larger carbohydrates are made, which leads to a node labelled Join by condensation reactions, which in turn branches to two nodes: Disaccharides and Polysaccharides. The second arrow from Monosaccharides goes to a node labelled Common monosaccharides, which branches to three nodes: Glucose, Galactose and Fructose.

    • 1Box 1

    • 2Box 2

    • 3Box 3

    0 of 3 labelled

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