The effect of pH on the rate of an enzyme reaction: practical | Starter Quiz | Oak National Academy

What is starch made of?

• amino acids

• sugars

• fatty acids

• glycerol

Answer explanation

Starch is made of sugars joined together.

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

Answer explanation

Amylase 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'.

• enzyme amount

• independent variable

• rate of reaction

• dependent variable

• pH

• control variable

Answer explanation

The independent variable is what is chosen or changed and the dependent variables are those that are measured. Control variables are kept the same.

Is this a positive or negative test for starch?

• positive

• negative

Answer explanation

In the presence of starch, iodine turns from an orange/brown colour to a dark blue/black colour.

Who best describes what rate of reaction is?

• 
• 
• 
• 

Answer explanation

Rate of reaction is measured by measuring how much product is formed (e.g. in grams) in a period of time (e.g. seconds or minutes).