Explaining effects of substrate concentration and temperature on enzyme rate | Combined science

Starter quiz

What region on an enzyme does the substrate bind to?

substrate site

active site ✓

complex site

enzyme substrate complex site
Put the steps in order to show how an enzyme works.

1

⇔

The substrate and enzyme collide.

2

⇔

The substrate binds to the enzyme.

3

⇔

An enzyme substrate complex forms.

4

⇔

A chemical reaction takes place.

5

⇔

The product(s) are released.

6

⇔

The enzyme is free to catalyse another reaction.
Enzymes ______ the amount of activation energy needed for a reaction to take place.

'lower' ✓
The shape of the active site is ______ to the substrate.

'complementary' ✓
Which of the following are enzymes?

lactose

lactase ✓

maltose

maltase ✓

amylase ✓
What type of molecule are enzymes?

proteins ✓

lipids

carbohydrates

amino acids

Which part of an enzyme does the substrate need to collide with for a reaction to take place?

'active site' ✓
What is the rate of reaction?

how much substrate has been used up

how much substrate has not been used up

how long it took for the reaction to finish

how much product is formed per unit of time ✓
Below are two graphs showing the rates of enzyme facilitated reactions. Match the graph to the factor affecting the rate of reaction.

temperature

⇔

graph B ✓

concentration of substance

⇔

graph A ✓
Put these steps in order to show what happens as the temperature of an enzyme controlled reaction increases.

1

⇔

As temperature increases, molecules move faster as they have more energy.

2

⇔

The rate of reaction increases, to its optimum.

3

⇔

The bonds holding the enzyme molecules together start to break.

4

⇔

The enzyme's active site changes shape and the substrate no longer fits.

5

⇔

The rate of reaction slows to zero as all the enzyme molecules become denatured.
Where on the graph is the substrate concentration greater than the enzyme concentration?

X

Y ✓
Where on the graph could the enzyme concentration be greater than substrate concentration?

A ✓

B

C

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The rate of a reaction is the amount of change (e.g. substrate broken down or product made) per unit of time.
Enzyme reaction rate increases as substrate concentration increases until an optimum when all active sites are full.
Enzyme reaction rate increases with temperature due to more collisions, until an optimum when all active sites are full.
Enzyme rate decreases as temperature increases above the optimum as bonds break and the active site becomes denatured.
Interpretation of graphs showing effects of substrate concentration and temperature on enzyme reaction rate.

Enzymes die rather than denature.

The word denature is clearly introduced and a CfU explores the word die vs denature.

Rate of reaction - A measure of how much change occurs per unit of time.
Concentration - A measure of the quantity of a dissolved substance in a given volume of solution.
Optimum - The conditions where maximum rate of reaction occurs.
Bond - A force of attraction between atoms in a compound.
Denatured - A permanent change in the shape of an enzyme that stops it from working properly.