Topic Three (1.3): Lipids and Proteins

Introduction Icon.png Introduction

Lipids and proteins are both formed by condensation reactions similar to carbohydrates, but while ester and glycosidic bonds both form by combining two adjacent OH groups, peptide bonds in proteins form by combining the H from the amine end of one amino acid, and the OH from the acid end of another.

While questions about carbohydrates often focus on the condensation reactions, though, questions about lipids are often concentrated on the differences between saturated and unsaturated fatty acids, and questions about proteins usually focus on the tertiary structure and the bonds that make their shapes so specific.

Read Icon.png Reading

Edexcel AS/A Level Biology Student Book 1 pages 14 to 21, page 25

Read & Make Notes Icon.png Read and Make Notes

Read pages 14 to 15, making appropriate notes and completing the ‘in-text’ questions.

Consolidate Icon.png Consolidate

Now consolidate your understanding by working through these additional resources:

Download READ – Lipids Factsheet 1

Download READ – Lipids Factsheet 2

Download REVIEW – Lipids Concept Map

EXPLORE – Lipids Topic (Khan Academy) Links to an external site.

WATCH – Triglyceride Formation (Nutrition) Links to an external site.

Read & Make Notes Icon.png Read and Make Notes

Read pages 16 to 21, making appropriate notes and completing the ‘in-text’ questions.

Consolidate Icon.png Consolidate

Now consolidate your understanding by working through these additional resources:

EXPLORE – Proteins Topics (Khan Academy) Links to an external site.

Download COMPLETE – Protein Structure Worksheet

Download CHECK – Protein Structure Worksheet – Answers

Download REVIEW – The Structure of Proteins (PowerPoint)

READ – Proteins Poster Download READ – Proteins Poster

Download REVIEW – Proteins Factsheet

REVIEW – Biuret Test (Online Biology Notes) Links to an external site.

Make Notes Icon.png Tasks

Complete the following:

  • Complete questions 5 and 6 on page 25.

Top Tip Icon.png Top Tips

Make sure that you understand the following key points:

  • The difference between saturated and unsaturated fatty acids and what that means for their properties.
  • Be able to draw the formation of a triglyceride from glycerol and 3 fatty acids.
  • Know the importance of the primary structure of proteins in determining their tertiary structure.
  • Know all of the tertiary structure bond types.

Glossary Icon.png Key Terms

Check that you know all of the terms in the Subject Vocabulary boxes on pages 15 and 21 and add any you don’t know to your glossary.