A Level Biology Lesson 16:

Enzymes Lower Activation Energy.

Task 1. Check Where this Lesson fits into your Exam Specification!

Task 2. Watch the Revision Notes Lesson in Full.

00:00 Intro Screen / Learning Outcomes

00:36 Enzymes are biological catalysts...

02:10 Enzymes are intracellular and extracellular...

02:40 NOTE - Know enzymes is good for synoptic essays!

03:15 Chemical reaction need energy... Enzymes Lower Activation Energy...

03:30 Activation Energy is usually provided in the form of Heat...

04:05 The peak - is the transition state...

04:35 Graph to show the amount of activation energy needed without an enzyme.

06:23 Graph to show the amount of activation energy needed WITH an enzyme.

07:11 In summary.

Task 3. 

Download, Print out & complete the accompanying Interactive Worksheet.


Check Your Spec!


★ AQA Specification Reference: - Many proteins are enzymes. Each enzyme lowers the activation energy of the reaction it catalyses. Students should be able to: appreciate that enzymes catalyse a wide range of intracellular and extracellular reactions that determine structures and functions from cellular to whole-organism level.


★ CIE Specification Reference: - 3 Enzymes. An understanding that an enzyme is a biological catalyst that increases the rate of a reaction and remains unchanged when the reaction is complete. 3.1 Mode of action of enzymes: a) explain that enzymes are globular proteins that catalyse metabolic reactions b) state that enzymes function inside cells (intracellular enzymes) and outside cells (extracellular enzymes).


★ Edexcel (Biology A – Salters-Nuffield) Specification Reference: - Topic 2: Genes and Health. 2.10. ii) Understand that enzymes are biological catalysts that reduce activation energy. iii) Know that there are intracellular enzymes catalysing reactions inside cells and extracellular enzymes produced by cells catalysing reactions outside of cells.


★ Edexcel (Biology B) Specification Reference: - Topic 1: Biological Molecules. 1.5 Enzymes. iii Understand that enzymes are catalysts that reduce activation energy. vii Know that enzymes catalyse a wide range of intracellular reactions as well as extracellular ones.


★ OCR (Biology A) Specification Reference: - Module 2 – Foundations in biology: 2.1.4 Enzymes. Metabolism in living organisms relies upon enzyme controlled reactions. (a) The role of enzymes in catalysing reactions that affect metabolism at a cellular and whole organism level. (b) the role of enzymes in catalysing both intracellular and extracellular reactions. (c) the mechanism of enzyme action - product formation and lowering of activation energy.


★ OCR (Biology B) Specification Reference: - Module 2 – Cells, chemicals for life, transport and gas exchange. 2.1.3 Proteins and enzymes: (c) how enzymes catalyse metabolic reactions. … the lowering of the activation energy.


★ WJEC Specification Reference: - Core Concepts: 4. Biological reactions are regulated by enzymes. Enzymes are vital in controlling metabolism in organisms. (c) enzymes acting intracellularly or extracellularly. (f) the meaning of catalysis; the lowering of the activation energy.


Remember Specifications are often very vague - No matter which exam board you are studying you need to know this.


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