A measure of how acidic or alkaline a solution is.

An enzyme that breaks down starch into maltose (a type of sugar).

A carbohydrate, which is a polysaccharide (a polymer of sugar).

A method that involves taking regular and frequent samples.

The effect of pH on the rate of an enzyme reaction: practical

Combined science

Biological molecules

Tests for biological molecules

Obtaining the elements needed to make biological molecules

Enzymes: function, structure and specificity

Effects of substrate concentration and temperature on rate of enzyme activity

The effect of pH on the rate of an enzyme reaction: plan

The effect of pH on the rate of an enzyme reaction: data analysis

Pupils will learn how substances essential for chemical reactions, and the products of the reactions, are transported into, around and out of the human body.

Pupils learned about differences in the cell structures of eukaryotic and prokaryotic organisms.

This unit explores the roles of sugars, amino acids, and fatty acids in the synthesis and breakdown of biological molecules. It covers enzyme action, transport in organisms, hypothesis development, and data interpretation. Emphasis is on planning experiments and presenting explanations.

Biological molecules and enzymes

Physical activity and equipment requiring safe use

Which piece of equipment would you use in this practical to heat the test tubes of starch and amylase to a specific temperature?

What is collecting data at accurately timed intervals know as?

What is formed when amylase digests starch?

Iodine solution is an irritant. What piece of safety equipment should be warn when using it?

What is this piece of equipment used for?

What is the enzyme that catalyses the breakdown of starch into maltose?

Match the variable to its description for the investigation 'Investigating the effect of changing pH on the rate of enzyme reaction'. 

Is this a positive or negative test for starch?

Sofia: How much substrate has been used up.

Izzy: How much product was formed when the reaction finished.

Jacob: How much product was formed every second.

Who best describes what rate of reaction is?

Measure 5 ml of starch and amylase solution into separate test tubes.

Place both test tubes in a water bath at 21 °C for five minutes.

Combine the solutions and mix gently. Return to the water bath.

Using a pipette, remove a sample of solution.

Test the solution in a spotting tile with iodine solution.

Continue testing every minute until the iodine solution stays orange/brown.

Order these steps to show how you would carry out an investigation into the effect of changing temperature on the rate of an enzyme-controlled reaction.

The effect of pH on the rate of an enzyme reaction: practical

Lesson outcome

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