2.2 Carbohydrates &amp; Lipids

Question 2b

Marks: 2

b)

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

[2 marks]

Key Concepts

Question 2c

Marks: 1

c)

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

[1 mark]

Key Concepts

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]

Key Concepts

Question 3a

Marks: 2

a)

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

[2 marks]

Key Concepts

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]

Key Concepts

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-

[2 marks]

Key Concepts

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]

Key Concepts

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]

Key Concepts

Question 4b

Marks: 2

b)

Define the term 'metabolic water'.

[2 marks]

Key Concepts

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]

Key Concepts

Body Mass Index Calculations

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.

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]

Key Concepts

Question 5b

Marks: 8

b)

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

[8 marks]

Key Concepts