A Level Biology Lesson 15:

Enzymes. A Summary of Basic Enzyme Properties.

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

Task 2. Watch the Revision Notes Lesson in Full.

00:00 intro screen -

00:13 Learning Outcomes

00:56 Enzymes are Specific...

01:52 The Active Site of an Enzyme is its Catalytic Centre.

02:21 The Enzyme-Substrate-complex

02:58 The Primary sequence of amino acids determines the 3D conformational shape of the enzyme.

03:31 Factors in the gene sequence can result in a different primary structure of the enzyme... 03:54 Other factors (e.g. pH and Temperature) can also affect the enzyme...

04:48 If the substrate and Active site are not complementary no Enzyme-Substrate-complex can form.

05:19 Enzymes lower activation energy... (Summary).

Task 3. 

Download, Print out & complete the accompanying Interactive Worksheet.


Check Your Spec!


★ AQA Specification Reference: - Many proteins are enzymes. The properties of an enzyme relate to the tertiary structure of its active site and its ability to combine with complementary substrate(s) to form an enzyme-substrate complex.


★ CIE Specification Reference: - 2.3 (Biological Molecules) Proteins: An understanding of protein structure and how it is related to function


★ Edexcel (Biology A – Salters-Nuffield) Specification Reference: - 2.10 (Topic 2: Genes and Health) Understand the mechanism of action and the specificity of enzymes in terms of their three-dimensional structure. ii) Understand that enzymes are biological catalysts that reduce activation energy.


★ Edexcel (Biology B) Specification Reference: - 1.5 (Enzymes) (i) Know the structure of enzymes as globular proteins, (ii) Enzymes Understand the concepts of specificity. (iii) Understand that enzymes are catalysts that reduce activation energy.


★ OCR (Biology A) Specification Reference: - 2.1.4 Enzymes. The role of enzymes in catalysing reactions - To include the idea that enzymes affect both structure and function.


★ OCR (Biology B) Specification Reference: - 2.1.3 Proteins and enzymes. How the structure of globular proteins enable enzyme molecules to catalyse specific metabolic reactions. To include the role of tertiary structure in the specificity of the active site, the formation of enzyme substrate complexes and the lowering of the activation energy.


★ WJEC Specification Reference: - 1. Basic Biochemistry and Cell Organisation (j) the relationship of the fibrous and globular structure of proteins to their function.


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



Darwin T




1Fractured DNA



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