Cambridge (CIE) AS Your notes
Biology
Carbohydrates & Lipids
Contents
Biological Molecules: Key Terms
Covalent Bonds in Polymers
Reducing & Non-Reducing Sugars
The Glycosidic Bond
Starch & Glycogen
Cellulose
Triglycerides
Phospholipids
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, Biological Molecules: Key Terms
Your notes
The Two Forms of Glucose
The most well-known carbohydrate monomer is glucose
Glucose has the molecular formula C6H12O6
Glucose is the most common monosaccharide and is of central importance to most
forms of life
There are different types of monosaccharide formed from molecules with varying
numbers of carbon atom, for example:
Trioses (3C) e.g. glyceraldehyde
Pentoses (5C) e.g. ribose
Hexoses (6C) e.g. glucose
Glucose exists in two structurally different forms – alpha (α) glucose and beta (β)
glucose and is therefore known as an isomer
This structural variety results in different functions between carbohydrates
Alpha and Beta Glucose Diagram
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, Your notes
Straight chain and ring structural formula of alpha & beta glucose
Different polysaccharides are formed from the two isomers of glucose
Structure of polysaccharides table
Polysaccharide Alpha Glucose Beta Glucose
Starch ✓ X
Glycogen ✓ X
Cellulose X ✓
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, Your notes
Examiner Tips and Tricks
You must be able to recognise and draw the isomer rings of α and β glucose.
Biological Molecules: Key Terms
The key molecules that are required to build structures that enable organisms to
function are:
Carbohydrates
Proteins
Lipids
Nucleic Acids
Water
Biological Molecules Diagram
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Biology
Carbohydrates & Lipids
Contents
Biological Molecules: Key Terms
Covalent Bonds in Polymers
Reducing & Non-Reducing Sugars
The Glycosidic Bond
Starch & Glycogen
Cellulose
Triglycerides
Phospholipids
© 2025 Save My Exams, Ltd. Get more and ace your exams at savemyexams.com 1
, Biological Molecules: Key Terms
Your notes
The Two Forms of Glucose
The most well-known carbohydrate monomer is glucose
Glucose has the molecular formula C6H12O6
Glucose is the most common monosaccharide and is of central importance to most
forms of life
There are different types of monosaccharide formed from molecules with varying
numbers of carbon atom, for example:
Trioses (3C) e.g. glyceraldehyde
Pentoses (5C) e.g. ribose
Hexoses (6C) e.g. glucose
Glucose exists in two structurally different forms – alpha (α) glucose and beta (β)
glucose and is therefore known as an isomer
This structural variety results in different functions between carbohydrates
Alpha and Beta Glucose Diagram
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, Your notes
Straight chain and ring structural formula of alpha & beta glucose
Different polysaccharides are formed from the two isomers of glucose
Structure of polysaccharides table
Polysaccharide Alpha Glucose Beta Glucose
Starch ✓ X
Glycogen ✓ X
Cellulose X ✓
© 2025 Save My Exams, Ltd. Get more and ace your exams at savemyexams.com 3
, Your notes
Examiner Tips and Tricks
You must be able to recognise and draw the isomer rings of α and β glucose.
Biological Molecules: Key Terms
The key molecules that are required to build structures that enable organisms to
function are:
Carbohydrates
Proteins
Lipids
Nucleic Acids
Water
Biological Molecules Diagram
© 2025 Save My Exams, Ltd. Get more and ace your exams at savemyexams.com 4
