1.4 condensation, hydrolysis and glycosidic bonds

What is a condensation reaction?

A reaction in which two molecules join together and a molecule of water is removed.

What happens to water during condensation?

Water is removed.

What happens to the molecules during condensation?

They join together and a new bond is formed.

What is hydrolysis?

A reaction in which a bond is broken by the addition of water.

What happens to water during hydrolysis?

Water is added.

What is the relationship between condensation and hydrolysis?

They are opposite processes: condensation removes water to form a bond

What type of bond forms when monosaccharides join?

A glycosidic bond.

What type of reaction forms a glycosidic bond?

A condensation reaction.

What type of reaction breaks a glycosidic bond?

A hydrolysis reaction.

What is a glycosidic bond?

A covalent bond joining monosaccharide units.

What does 1

4-glycosidic bond mean?

What does 1

6-glycosidic bond mean?

⭐ What is the significance of a 1

6-glycosidic bond?

⭐ What is the significance of a 1

4-glycosidic bond?

What happens when a disaccharide undergoes hydrolysis?

Water is added and the glycosidic bond is broken

What happens when a polysaccharide undergoes hydrolysis?

Water is added to break glycosidic bonds

⭐ Describe the formation of maltose.

Two α-glucose molecules undergo a condensation reaction

⭐ Describe the hydrolysis of maltose.

Water is added to break the glycosidic bond

⭐ Complete: glucose + glucose → ?

Maltose + water.

⭐ Complete: glucose + fructose → ?

Sucrose + water.

⭐ Complete: glucose + galactose → ?

Lactose + water.

⭐ A reaction joins two monosaccharides and releases water. What type of reaction has occurred?

A condensation reaction.

⭐ A reaction breaks a disaccharide into two monosaccharides. What type of reaction has occurred?

A hydrolysis reaction.

⭐ A student says hydrolysis forms glycosidic bonds. Explain the error.

Hydrolysis breaks glycosidic bonds by adding water; glycosidic bonds are formed by condensation reactions.

⭐ Explain how condensation and hydrolysis are linked in carbohydrate metabolism.

Condensation joins monosaccharides by removing water and forming glycosidic bonds

The specification explicitly requires knowing how glucose

fructose and galactose form maltose

The textbook likewise describes glycosidic bonds as being formed through condensation and broken through hydrolysis.

🟩 1.5 — LIPIDS

Question

Answer

What are the two main components needed to make a triglyceride?

One glycerol molecule and three fatty acid molecules.

What is a triglyceride?

A lipid molecule consisting of glycerol joined to three fatty acids.

How many fatty acids combine with one glycerol to form a triglyceride?

Three.

What type of reaction forms a triglyceride?

Condensation reactions.

What type of bond forms between glycerol and fatty acids?

Ester bonds.

How many ester bonds are formed when one triglyceride is synthesised?

Three.

How many water molecules are released when one triglyceride is formed?

Three.

⭐ Complete: glycerol + 3 fatty acids → ?

Triglyceride + 3H₂O.

What is an ester bond?

A bond formed between glycerol and a fatty acid during triglyceride synthesis.

⭐ Explain how a triglyceride is formed.

One glycerol molecule reacts with three fatty acid molecules in condensation reactions. Three ester bonds form and three molecules of water are released.

What is a saturated fatty acid?

A fatty acid containing no carbon-carbon double bonds.

What is an unsaturated fatty acid?

A fatty acid containing one or more carbon-carbon double bonds.

What is a monounsaturated fatty acid?

A fatty acid containing one carbon-carbon double bond.

What is a polyunsaturated fatty acid?

A fatty acid containing more than one carbon-carbon double bond.

What is the key structural difference between saturated and unsaturated fatty acids?

Saturated fatty acids contain only single carbon-carbon bonds

⭐ A fatty acid contains three C=C bonds. Is it saturated or unsaturated?

Unsaturated; specifically polyunsaturated.

⭐ A fatty acid contains no C=C bonds. Is it saturated or unsaturated?

Saturated.

⭐ Why are triglycerides effective energy stores?

They contain many energy-rich C–H bonds and can release substantial energy when oxidised during respiration.

⭐ How does the structure of a triglyceride relate to its role as an energy store?

A triglyceride contains three fatty acid chains with many C–H bonds

⭐ Compare saturated and unsaturated fatty acids.

Saturated fatty acids contain no C=C double bonds

⭐ A triglyceride contains three fatty acids. How many ester bonds should be present?

Three ester bonds.

⭐ A student claims that a triglyceride forms by hydrolysis. Correct the statement.

A triglyceride forms by condensation reactions between glycerol and three fatty acids; hydrolysis would break the ester bonds.

⭐ What happens to a triglyceride during hydrolysis?

Water is added to break the ester bonds